Professor Tao Dong

Research Area: Immunology
Technology Exchange: Bioinformatics, Cell sorting, Cellular immunology, Computational biology, Flow cytometry, Immunohistochemistry, Mass spectrometry, Microscopy (Confocal), Microscopy (EM), SNP typing and Transcript profiling
Scientific Themes: Immunology & Infectious Disease and Cancer Biology
Keywords: Influenza, Cancer immunology, CTL, HBV/HCC, China, HPV/CC, EBV/NPC, T cell epitope mapping, T cell receptor and immune checkpoint receptor
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The main objective of my group’s research is to focus on the functional aspects of the antigen specific T cells and studying the factors affecting T cells in controlling virus infection and cancer development.

For important human infections, cancer development and the course of disease is influenced mainly by the T cell response - while a robust and appropriate T cell response is beneficial to the host, a weak or inappropriate response can be ineffective or even have a detrimental effect. Numerous factors influence the quality of the T cell response to viral infections, predominant among them being the microenvironment of the infection site, the type of cells infected and the variability of the virus. By understanding the key factors required for efficient viral control by the T cell response in a number of different viral infections and viral associated cancer, we aim to augment and control the immune response to as a way of improving the outcome of in several important human diseases. Current research program  including:

  • To define the impact of IFTIM3 genetic variation on Influenza, and other virus infection, immune responses and disease outcome
  • To study the Viral OncoProtein(VOP) and Tumor Specific Protein(TSP) specific T cell responses in virus associated cancer (I.e. HBV/HCC; EBV/NPC and HPV/CC)
  • To identify the factors determining functional avidity and anti-viral/cancer efficacy of antigen specific T cells in cancer micro-environment

Name Department Institution Country
Dr YongHong Zhang Capital Medical University BeiJing Capital University, Youan Hospital China
Professor Rou-Zheng Wang Xinjiang Tumour Hospital China
Professor Sir Andrew J McMichael NDM Research Building Oxford University, NDM Research Building United Kingdom
Professor Ling-Pei Ho Experimental Medicine Division Oxford University, Weatherall Institute of Molecular Medicine United Kingdom
Professor Mary Carrington National Cancer Institute United States
Professor Jane McKeating NDM Research Building Oxford University, NDM Research Building United Kingdom
Culshaw A, Ladell K, Gras S, McLaren JE, Miners KL, Farenc C, van den Heuvel H, Gostick E, Dejnirattisai W, Wangteeraprasert A et al. 2017. Germline bias dictates cross-serotype reactivity in a common dengue-virus-specific CD8+ T cell response. Nat Immunol, 18 (11), pp. 1228-1237. | Show Abstract | Read more

Adaptive immune responses protect against infection with dengue virus (DENV), yet cross-reactivity with distinct serotypes can precipitate life-threatening clinical disease. We found that clonotypes expressing the T cell antigen receptor (TCR) β-chain variable region 11 (TRBV11-2) were 'preferentially' activated and mobilized within immunodominant human-leukocyte-antigen-(HLA)-A*11:01-restricted CD8+ T cell populations specific for variants of the nonstructural protein epitope NS3133 that characterize the serotypes DENV1, DENV3 and DENV4. In contrast, the NS3133-DENV2-specific repertoire was largely devoid of such TCRs. Structural analysis of a representative TRBV11-2+ TCR demonstrated that cross-serotype reactivity was governed by unique interplay between the variable antigenic determinant and germline-encoded residues in the second β-chain complementarity-determining region (CDR2β). Extensive mutagenesis studies of three distinct TRBV11-2+ TCRs further confirmed that antigen recognition was dependent on key contacts between the serotype-defined peptide and discrete residues in the CDR2β loop. Collectively, these data reveal an innate-like mode of epitope recognition with potential implications for the outcome of sequential exposure to heterologous DENVs.

Pan Y, Yang P, Dong T, Zhang Y, Shi W, Peng X, Cui S, Zhang D, Lu G, Liu Y et al. 2017. IFITM3 Rs12252-C Variant Increases Potential Risk for Severe Influenza Virus Infection in Chinese Population. Front Cell Infect Microbiol, 7 (JUN), pp. 294. | Show Abstract | Read more

Background: Interferon Inducible Transmembrane 3 (IFITM3) is a key factor in interferon pathway and it involves host's immune response against multiple viruses. IFITM3 rs12252-C was associated with severe influenza virus infection in several studies, however whether this association is universal to all types of influenza virus or diverse ethnic populations remain controversial. Method: A case-control genetic association study was performed from September 2013 to April 2014 and September 2014 to April 2015. All samples were tested for influenza using RT-PCR, and genotyped by High Resolution Melting assay. Results: A total of 65 healthy people, 165 mild influenza-like illness (ILI) cases and 315 severe acute respiratory infection (SARI) cases were enrolled in this study. The frequency of CC genotype was much higher in SARI cases with IVI than that in ILI cases with IVI (61.59 vs. 27.16%), leading a 4.67-fold greater risk for severe IVI than other two genotypes. Moreover, the risk of IFITM3 rs12252-C variant for severe IVI was specific for both influenza A and influenza B. Conclusion:IFITM3 rs12252 CC genotype was associated with severity rather than susceptibility of IVI in Chinese population, and this strong effect was observed in all subtypes of seasonal influenza infection.

Cole SL, Dunning J, Kok WL, Benam KH, Benlahrech A, Repapi E, Martinez FO, Drumright L, Powell TJ, Bennett M et al. 2017. M1-like monocytes are a major immunological determinant of severity in previously healthy adults with life-threatening influenza. JCI Insight, 2 (7), | Show Abstract | Read more

In each influenza season, a distinct group of young, otherwise healthy individuals with no risk factors succumbs to life-threatening infection. To better understand the cause for this, we analyzed a broad range of immune responses in blood from a unique cohort of patients, comprising previously healthy individuals hospitalized with and without respiratory failure during one influenza season, and infected with one specific influenza A strain. This analysis was compared with similarly hospitalized influenza patients with known risk factors (total of n = 60 patients recruited). We found a sustained increase in a specific subset of proinflammatory monocytes, with high TNF-α expression and an M1-like phenotype (independent of viral titers), in these previously healthy patients with severe disease. The relationship between M1-like monocytes and immunopathology was strengthened using murine models of influenza, in which severe infection generated using different models (including the high-pathogenicity H5N1 strain) was also accompanied by high levels of circulating M1-like monocytes. Additionally, a raised M1/M2 macrophage ratio in the lungs was observed. These studies identify a specific subtype of monocytes as a modifiable immunological determinant of disease severity in this subgroup of severely ill, previously healthy patients, offering potential novel therapeutic avenues.

Cole SL, Dunning J, Kok WL, Benam KH, Benlahrech A, Repapi E, Martinez FO, Drumright L, Powell TJ, Bennett M et al. 2017. M1-like monocytes are a major immunological determinant of severity in previously healthy adults with life-threatening influenza. JCI Insight, 2 (7), pp. e91868. | Show Abstract | Read more

In each influenza season, a distinct group of young, otherwise healthy individuals with no risk factors succumbs to life-threatening infection. To better understand the cause for this, we analyzed a broad range of immune responses in blood from a unique cohort of patients, comprising previously healthy individuals hospitalized with and without respiratory failure during one influenza season, and infected with one specific influenza A strain. This analysis was compared with similarly hospitalized influenza patients with known risk factors (total of n = 60 patients recruited). We found a sustained increase in a specific subset of proinflammatory monocytes, with high TNF-α expression and an M1-like phenotype (independent of viral titers), in these previously healthy patients with severe disease. The relationship between M1-like monocytes and immunopathology was strengthened using murine models of influenza, in which severe infection generated using different models (including the high-pathogenicity H5N1 strain) was also accompanied by high levels of circulating M1-like monocytes. Additionally, a raised M1/M2 macrophage ratio in the lungs was observed. These studies identify a specific subtype of monocytes as a modifiable immunological determinant of disease severity in this subgroup of severely ill, previously healthy patients, offering potential novel therapeutic avenues.

Wang R-Z, Zhang D-G, Wu R, Hu Y-H, Peng Y-C, Chang C, Dong T, Wang X-Y. 2016. HLA-A*02-B*46 haplotype: an adverse prognostic factor in Han patients with nasopharyngeal carcinoma. J Huazhong Univ Sci Technolog Med Sci, 36 (5), pp. 700-704. | Show Abstract | Read more

Epidemiological studies have shown that human leukocyte antigen (HLA) allelic polymorphisms are closely correlated to susceptibility to nasopharyngeal carcinoma (NPC), and in a previous study, we showed that HLA-B*46 and HLA-A*02-B*46 haplotypes were strongly associated with NPC susceptibility. In this retrospective study, we investigated the phenotype of the HLA-A and HLA-B alleles and haplotypes and correlated these data to the clinical and pathological parameters of NPC to understand the role of HLA alleles and haplotypes in NPC prognosis. The cohort comprised 117 NPC patients from a Han population in Xinjiang. The local recurrence-free survival (LRFS), distant metastasis- free survival (DMFS), disease-free survival (DFS), and overall survival (OS) were analyzed. The 5-year DMFS of the HLA-A*02-B*46 haplotype carriers and non-carriers was 66.4% and 90.3%, respectively. In addition, age was found to be a prognostic factor for LRFS, DFS, and OS (P=0.032, 0.040, and 0.013, respectively). We found that the HLA-A*02-B*46 haplotype might be a prognostic marker in addition to the traditional TNM staging in patients with NPC.

Jiang F, Han X, Zhang H, Zhao B, An M, Xu J, Chu Z, Dong T, Shang H. 2016. Multi-layered Gag-specific immunodominant responses contribute to improved viral control in the CRF01_AE subtype of HIV-1-infected MSM subjects. BMC Immunol, 17 (1), pp. 28. | Show Abstract | Read more

BACKGROUND: The purpose of this study was to characterize specific cytotoxic T-cell (CTL) responses in men who have sex with men (MSM) subjects infected with the human immunodeficiency virus type 1 (HIV-1) CRF01_AE subtype during the first year of infection and impacts on viral control and evolution. RESULTS: Fifteen HIV-1 primary infected cases were recruited from Liaoning MSM prospective cohort. CTL responses to Gag, Pol and Nef proteins at 3 month and 1 year post infection were detected with Gamma interferon enzyme-linked immunospot (ELISPOT) assay using optimized consensus overlapping peptides, as well as the viral quasispecies sequences from the synchronous plasma. Gag and Nef proteins were the main targets of CTL responses during the first year of HIV-1 infection, and this was evident from the data after adjusting for the length of amino acids by dividing the amino acids number of the corresponding protein and multiplying by 100. Additionally, relative magnitudes of Gag at both 3 months and 1 year post infection were significantly negatively correlated with the viral set point (p = 0.002, r = -0.726; p = 0.025, r = -0.574). While the relative magnitude of Nef at 1 year post infection were significantly positively correlated with viral set point (p = 0.004, r = 0.697). Subjects with multi-layered Gag immunodominant responses during the first year of infection had significantly lower viral set points than subjects without such responses (p = 0.002). CONCLUSION: Multi-layered Gag immunodominant responses during the first year of infection were correlated with viral control, which provides a theoretical basis for vaccine design targeting MSM subjects with the CRF01_AE subtype.

Geng X-T, Hu Y-H, Dong T, Wang R-Z. 2016. Associations of Human Leukocyte Antigen-DRB1 Alleles with Nasopharyngeal Carcinoma and Its Clinical Significance in Xinjiang Uyghur Autonomous Region of China. Chin Med J (Engl), 129 (11), pp. 1347-1354. | Show Abstract | Read more

BACKGROUND: Genetic susceptibility is one of the major etiological factors for nasopharyngeal carcinoma (NPC). Among the genetic predisposing factors, human leukocyte antigen (HLA) genes have been reported to be associated with NPC. This study aimed to investigate the associations of HLA-DRB1 alleles with NPC and the clinical significance of HLA-DRB1 alleles in NPC. METHODS: From January 2009 to December 2013, 140 NPC patients (118 Han patients and 22 Uyghur patients) and 158 healthy controls (81 Han individuals and 77 Uyghur individuals) from Xinjiang Province were genotyped for HLA-DRB1 using the polymerase chain reaction-sequence specific primer technique. Chi-square analysis was used when comparing allele frequencies between groups. The clinical outcomes were evaluated by Kaplan-Meier method and Cox regression model. RESULTS: Compared with healthy controls, the allele frequency of HLA-DRB1*0701 was increased in the Uyghur patients (P = 0.008) but not in the Han patients (P = 0.869). HLA-DRB1*0101 allele was presented with higher frequency in clinical Stage I + II group compared with clinical Stage III + IV group in the Han patients (P = 0.015) but not in the Uyghur patients (P = 1.000). Higher frequency of HLA-DRB1*1501 allele was observed in patients aged <45 years compared with those in patients aged ≥45 years (P = 0.002). Neither HLA-DRB1*0701 nor HLA-DRB1*0101 had a statistically significant association with 3-year survival. CONCLUSIONS: This study found HLA-DRB1*0701 in Uyghur population was associated with an increased risk of developing NPC. In Han population, we found HLA-DRB1*0101 was associated with protection from disease progression, and HLA-DRB1*1501 was associated with early age of onset. HLA-DRB1 could not be identified as a prognostic indicator for NPC in either Han or Uyghur patients.

Ström P, Støer N, Borthwick N, Dong T, Hanke T, Reilly M. 2016. A statistical approach to determining responses to individual peptides from pooled-peptide ELISpot data. J Immunol Methods, 435 pp. 43-49. | Show Abstract | Read more

To investigate in detail the effect of infection or vaccination on the human immune system, ELISpot assays are used to simultaneously test the immune response to a large number of peptides of interest. Scientists commonly use "peptide pools", where, instead of an individual peptide, a test well contains a group of peptides. Since the response from a well may be due to any or many of the peptides in the pool, pooled assays usually need to be followed by confirmatory assays of a number of individual peptides. We present a statistical method that enables estimation of individual peptide responses from pool responses using the Expectation Maximization (EM) algorithm for "incomplete data". We demonstrate the accuracy and precision of these estimates in simulation studies of ELISpot plates with 90 pools of 6 or 7 peptides arranged in three dimensions and three Mock wells for the estimation of background. In analysis of real pooled data from 6 subjects in a HIV-1 vaccine trial, where 199 peptides were arranged in 80 pools if size 9 or 10, our estimates were in very good agreement with the results from individual-peptide confirmatory assays. Compared to the classical approach, we could identify almost all the same peptides with high or moderate response, with less than half the number of confirmatory tests. Our method facilitates efficient use of the information available in pooled ELISpot data to avoid or reduce the need for confirmatory testing. We provide an easy-to-use free online application for implementing the method, where on uploading two spreadsheets with the pool design and pool responses, the user obtains the estimates of the individual peptide responses.

Nakaya HI, Clutterbuck E, Kazmin D, Wang L, Cortese M, Bosinger SE, Patel NB, Zak DE, Aderem A, Dong T et al. 2016. Systems biology of immunity to MF59-adjuvanted versus nonadjuvanted trivalent seasonal influenza vaccines in early childhood. Proc Natl Acad Sci U S A, 113 (7), pp. 1853-1858. | Show Abstract | Read more

The dynamics and molecular mechanisms underlying vaccine immunity in early childhood remain poorly understood. Here we applied systems approaches to investigate the innate and adaptive responses to trivalent inactivated influenza vaccine (TIV) and MF59-adjuvanted TIV (ATIV) in 90 14- to 24-mo-old healthy children. MF59 enhanced the magnitude and kinetics of serum antibody titers following vaccination, and induced a greater frequency of vaccine specific, multicytokine-producing CD4(+) T cells. Compared with transcriptional responses to TIV vaccination previously reported in adults, responses to TIV in infants were markedly attenuated, limited to genes regulating antiviral and antigen presentation pathways, and observed only in a subset of vaccinees. In contrast, transcriptional responses to ATIV boost were more homogenous and robust. Interestingly, a day 1 gene signature characteristic of the innate response (antiviral IFN genes, dendritic cell, and monocyte responses) correlated with hemagglutination at day 28. These findings demonstrate that MF59 enhances the magnitude, kinetics, and consistency of the innate and adaptive response to vaccination with the seasonal influenza vaccine during early childhood, and identify potential molecular correlates of antibody responses.

Zhang Y-H, Zhao Y, Rajapaksa US, Lawrence TM, Peng Y-C, Liu J, Xu K, Hu K, Qin L, Liu N et al. 2016. A Comprehensive Analysis of the Impact of HIV on HCV Immune Responses and Its Association with Liver Disease Progression in a Unique Plasma Donor Cohort. PLoS One, 11 (7), pp. e0158037. | Show Abstract | Read more

OBJECTIVE: Human Immunodeficiency Virus (HIV) and Hepatitis C virus (HCV) co-infection is recognized as a major cause of morbidity and mortality among HIV-1 infected patients. Our understanding of the impact of HIV infection on HCV specific immune responses and liver disease outcome is limited by the heterogeneous study populations with genetically diverse infecting viruses, varying duration of infection and anti-viral treatment. METHODS: Viral-specific immune responses in a cohort of 151 HCV mono- and HIV co-infected former plasma donors infected with a narrow source of virus were studied. HCV and HIV specific T cell responses were correlated with clinical data. RESULTS: HIV-1 accelerated liver disease progression and decreased HCV specific T cell immunity. The magnitude of HCV specific T cell responses inversely correlated with lower HCV RNA load and reduced liver injury as assessed by non-invasive markers of liver fibrosis. HIV co-infection reduced the frequency of HCV specific CD4+ T cells with no detectable effect on CD8+ T cells or neutralizing antibody levels. CONCLUSION: Our study highlights the impact of HIV co-infection on HCV specific CD4+ T cell responses in a unique cohort of patients for both HCV and HIV and suggests a crucial role for these cells in controlling chronic HCV replication and liver disease progression.

Jallow S, Leligdowicz A, Kramer HB, Onyango C, Cotten M, Wright C, Whittle HC, McMichael A, Dong T, Kessler BM, Rowland-Jones SL. 2015. Correction. The presence of prolines in the flanking region of an immunodominant HIV-2 gag epitope influences the quality and quantity of the epitope generated. Eur J Immunol, 45 (9), pp. 2701. | Read more

Dong T. 2015. CD8+ cytotoxic T lymphocytes in human influenza virus infection. Natl Sci Rev, 2 (3), pp. 264-265. | Read more

Yindom L-M, Wang L, Xu K, Dong T, Rowland-Jones SL. 2015. The identification of a killer cell immunoglobulin-like receptor 3DL1*0150209 in an Asian population using molecular techniques TISSUE ANTIGENS, 86 (2), pp. 152-153. | Read more

Bridgeman A, Maelfait J, Davenne T, Partridge T, Peng Y, Mayer A, Dong T, Kaever V, Borrow P, Rehwinkel J. 2015. Viruses transfer the antiviral second messenger cGAMP between cells. Science, 349 (6253), pp. 1228-1232. | Show Abstract | Read more

Cyclic GMP-AMP synthase (cGAS) detects cytosolic DNA during virus infection and induces an antiviral state. cGAS signals by synthesis of a second messenger, cyclic GMP-AMP (cGAMP), which activates stimulator of interferon genes (STING). We show that cGAMP is incorporated into viral particles, including lentivirus and herpesvirus virions, when these are produced in cGAS-expressing cells. Virions transferred cGAMP to newly infected cells and triggered a STING-dependent antiviral program. These effects were independent of exosomes and viral nucleic acids. Our results reveal a way by which a signal for innate immunity is transferred between cells, potentially accelerating and broadening antiviral responses. Moreover, infection of dendritic cells with cGAMP-loaded lentiviruses enhanced their activation. Loading viral vectors with cGAMP therefore holds promise for vaccine development.

Wang L, Zhang Y, Dong T, Rowland-Jones SL, Yindom L-M. 2015. KIR3DS1*0130109: a novel activating three-domain KIR identified using sequence-based typing. Tissue Antigens, 86 (3), pp. 222-223. | Show Abstract | Read more

KIR3DS1*0130109 is similar to KIR3DS1*0130101 except for a A > G change in intron 4.

Wang L, Zhang Y, Dong T, Rowland-Jones SL, Yindom L-M. 2015. Detection of a novel KIR3DL1*0150210 allele by sequencing. Tissue Antigens, 86 (4), pp. 311. | Show Abstract | Read more

KIR3DL1*0150210 has seven point mutations compared to the common Asian allele KIR3DL1*0150201.

Yindom L-M, Wang L, Xu K, Dong T, Rowland-Jones SL. 2015. The identification of a killer cell immunoglobulin-like receptor 3DL1*0150209 in an Asian population using molecular techniques. Tissue Antigens, 86 (2), pp. 152-153. | Show Abstract | Read more

Full-length sequences of KIR3DL1*0150209 differ from those of KIR3DL1*0150201 with seven single-nucleotide polymorphisms.

Jallow S, Leligdowicz A, Kramer HB, Onyango C, Cotten M, Wright C, Whittle HC, McMichael A, Dong T, Kessler BM, Rowland-Jones SL. 2015. The presence of prolines in the flanking region of an immunodominant HIV-2 gag epitope influences the quality and quantity of the epitope generated. Eur J Immunol, 45 (8), pp. 2232-2242. | Show Abstract | Read more

Both the recognition of HIV-infected cells and the immunogenicity of candidate CTL vaccines depend on the presentation of a peptide epitope at the cell surface, which in turn depends on intracellular antigen processing. Differential antigen processing maybe responsible for the differences in both the quality and the quantity of epitopes produced, influencing the immunodominance hierarchy of viral epitopes. Previously, we showed that the magnitude of the HIV-2 gag-specific T-cell response is inversely correlated with plasma viral load, particularly when responses are directed against an epitope, 165 DRFYKSLRA173 , within the highly conserved Major Homology Region of gag-p26. We also showed that the presence of three proline residues, at positions 119, 159 and 178 of gag-p26, was significantly correlated with low viral load. Since this proline motif was also associated with stronger gag-specific CTL responses, we investigated the impact of these prolines on proteasomal processing of the protective 165 DRFYKSLRA173 epitope. Our data demonstrate that the 165 DRFYKSLRA173 epitope is most efficiently processed from precursors that contain two flanking proline residues, found naturally in low viral-load patients. Superior antigen processing and enhanced presentation may account for the link between infection with HIV-2 encoding the "PPP-gag" sequence and both strong gag-specific CTL responses as well as lower viral load.

Zhang Y, Makvandi-Nejad S, Qin L, Zhao Y, Zhang T, Wang L, Repapi E, Taylor S, McMichael A, Li N et al. 2015. Interferon-induced transmembrane protein-3 rs12252-C is associated with rapid progression of acute HIV-1 infection in Chinese MSM cohort. AIDS, 29 (8), pp. 889-894. | Show Abstract | Read more

BACKGROUND: The interferon-inducible transmembrane protein-3 (IFITM3) is a protein that restricts multiple pathogenic viruses such as influenza virus. The single-nucleotide polymorphism rs12252-C, which is rare in Caucasian populations, but much more common in the Han Chinese population, has been found in much higher homozygous frequency in patients with severe acute influenza. Until now, there has been no study on the effect of this genetic variant on the clinical control of other viral infections. OBJECTIVES: To investigate the impact of IFITM3-rs12252 genotypes on primary HIV-1 infection progression in an acute HIV-1-infected cohort in Beijing (PRIMO), China. DESIGN AND METHODS: We identified IFITM3-rs12252 genotypes of 178 acute HIV-1-infected patients and 196 HIV-negative candidates from the PRIMO cohort. HIV-1 viral load and CD4(+) T-cell counts were monitored at multiple time points during the first year of infection, and the association between IFITM3-rs12252 genotype and disease progression was evaluated. RESULTS: The current study shows that the IFITM3-rs12252 genetic variant affects the progression of HIV-1 infection, but not the acquisition. A significantly higher frequency of the CC/CT genotypes was found in rapid progressors compared to nonprogressors. Patients with CC/CT genotypes showed an elevated peak viremia level and significantly lower CD4(+) T-cell count at multiple time points during the first year of primary infection, and a significantly higher risk of rapid decline of the CD4(+) T-cell count to below 350  cells/μl. CONCLUSION: A novel association between IFITM3 gene polymorphism and rapid disease progression is reported in an acute HIV-1-infected MSM cohort in China.

Zhang H, Han X, Zhao B, An M, Wang Z, Jiang F, Xu J, Zhang Z, Dong T, Shang H. 2015. Multilayered HIV-1 gag-specific T-cell responses contribute to slow progression in HLA-A*30-B*13-C*06-positive patients. AIDS, 29 (9), pp. 993-1002. | Show Abstract | Read more

OBJECTIVE: The HLA-A30-B13-C06 haplotype is reported to be associated with slow disease progression in the HIV-1-infected Northern Han Chinese population, but the mechanism remains unknown. DESIGN: Gag-specific T-cell responses and gag sequencing were performed in nine B' clade HIV-1-infected HLA-A30-B13-C06-positive slow progressors to understand HLA-associated viral control. METHODS: Interferon-γ ELISPOT assays were performed to determine the Gag-specific T-cell responses and cross-reactivity to variant peptides. Longitudinal HIV-1 gag sequencing was performed at the clonal level. RESULTS: The overlapping peptides (OLP)-48: RQANFLGKIWPSHKGRPGNF (RL42 Gag434-453); OLP-2: GQLDRWEKIRLRPGGKKKYR (RL42 Gag11-30); OLP-15: VQNLQGQMVHQPISPRTLNA (RL42 Gag135-154) and OLP-16: HQPISPRTLNAWVKVVEEKA (RL42 Gag144-163) were dominant in HLA-A30-B13-C06-positive patients. A new epitope [HQPISPRTL (Gag144-152, HL9)] within OLP-15 and OLP-16 was identified. Results showed that strong cross-reactive responses to multiple immunodominant peptides were associated with better clinical outcomes. In addition, efficient cross-recognition of HL9 autologous variants developed in patients was associated with high CD4 T-cell counts. However, two patients who had developed mutations to their dominant responses during the follow-up experienced decrease in CD4 T-cell counts. It appears that Gag-specific T-cell responses against one or more unmutated epitopes or cross-recognition of autologous epitope variants contribute to slow disease progression in HLA-A30-B13-C06-positive patients. CONCLUSION: We conclude that a single 'appropriate' Gag-specific T-cell response appears to be sufficient to protect patients from disease progression. HLA-A30-B13-C06-positive individuals benefited from having a choice of numerous immunodominant gag epitopes for T cells to react. The study offers new insight for future design of T-cell-based HIV-1 vaccine.

Jayasooriya S, de Silva TI, Njie-jobe J, Sanyang C, Leese AM, Bell AI, McAulay KA, Yanchun P, Long HM, Dong T et al. 2015. Early virological and immunological events in asymptomatic Epstein-Barr virus infection in African children. PLoS Pathog, 11 (3), pp. e1004746. | Show Abstract | Read more

Epstein-Barr virus (EBV) infection often occurs in early childhood and is asymptomatic. However, if delayed until adolescence, primary infection may manifest as acute infectious mononucleosis (AIM), a febrile illness characterised by global CD8+ T-cell lymphocytosis, much of it reflecting a huge expansion of activated EBV-specific CD8+ T-cells. While the events of AIM have been intensely studied, little is known about how these relate to asymptomatic primary infection. Here Gambian children (14-18 months old, an age at which many acquire the virus) were followed for the ensuing six months, monitoring circulating EBV loads, antibody status against virus capsid antigen (VCA) and both total and virus-specific CD8+ T-cell numbers. Many children were IgG anti-VCA-positive and, though no longer IgM-positive, still retained high virus loads comparable to AIM patients and had detectable EBV-specific T-cells, some still expressing activation markers. Virus loads and the frequency/activation status of specific T-cells decreased over time, consistent with resolution of a relatively recent primary infection. Six children with similarly high EBV loads were IgM anti-VCA-positive, indicating very recent infection. In three of these donors with HLA types allowing MHC-tetramer analysis, highly activated EBV-specific T-cells were detectable in the blood with one individual epitope response reaching 15% of all CD8+ T-cells. That response was culled and the cells lost activation markers over time, just as seen in AIM. However, unlike AIM, these events occurred without marked expansion of total CD8+ numbers. Thus asymptomatic EBV infection in children elicits a virus-specific CD8+ T-cell response that can control the infection without over-expansion; conversely, in AIM it appears the CD8 over-expansion, rather than virus load per se, is the cause of disease symptoms.

Wang L, Xu K, Dong T, Rowland-Jones SL, Yindom L-M. 2015. KIR3DS1*0130111: a novel KIR allele identified using molecular typing methods. Tissue Antigens, 85 (4), pp. 296-297. | Show Abstract | Read more

KIR3DS1*0130111 differs from KIR3DS1*0130101 with two previously undescribed single nucleotide polymorphisms.

Wang L, Zhang Y, Dong T, Rowland-Jones SL, Yindom LM. 2015. Detection of a novel KIR3DL1*0150210 allele by sequencing Tissue Antigens, 86 (4), pp. 311. | Read more

Wang L, Zhang Y, Dong T, Rowland-Jones SL, Yindom LM. 2015. KIR3DS1*0130109: A novel activating three-domain KIR identified using sequence-based typing Tissue Antigens, 86 (3), pp. 222-223. | Show Abstract | Read more

© 2015 John Wiley & Sons A/S. KIR3DS1*0130109 is similar to KIR3DS1*0130101 except for a A > G change in intron 4.

Yindom LM, Wang L, Xu K, Dong T, Rowland-Jones SL. 2015. The identification of a killer cell immunoglobulin-like receptor 3DL1*0150209 in an Asian population using molecular techniques Tissue Antigens, 86 (2), pp. 152-153. | Show Abstract | Read more

© 2015 John Wiley & Sons A/S. Full-length sequences of KIR3DL1*0150209 differ from those of KIR3DL1*0150201 with seven single-nucleotide polymorphisms.

Peng Y, Wang B, Talaat K, Karron R, Powell TJ, Zeng H, Dong D, Luke CJ, McMichael A, Subbarao K, Dong T. 2015. Boosted Influenza-Specific T Cell Responses after H5N1 Pandemic Live Attenuated Influenza Virus Vaccination. Front Immunol, 6 (JUN), pp. 287. | Show Abstract | Read more

BACKGROUND: In a phase I clinical trial, a H5N1 pandemic live attenuated influenza virus (pLAIV) VN2004 vaccine bearing avian influenza H5N1 hemagglutinin (HA) and NA genes on the A/Ann Arbor cold-adapted vaccine backbone displayed very restricted replication. We evaluated T cell responses to H5N1 pLAIV vaccination and assessed pre-existing T cell responses to determine whether they were associated with restricted replication of the H5N1 pLAIV. METHOD: ELISPOT assays were performed using pools of overlapping peptides spanning the entire H5N1 proteome and the HA proteins of relevant seasonal H1N1 and H3N2 viruses. We tested stored peripheral blood mononuclear cells (PBMCs) from 21 study subjects who received two doses of the H5N1 pLAIV. The PBMCs were collected 1 day before and 7 days after the first and second pLAIV vaccine doses, respectively. RESULT: T cell responses to conserved internal proteins M and NP were significantly boosted by vaccination (p = 0.036). In addition, H5N1 pLAIV appeared to preferentially stimulate and boost pre-existing seasonal influenza virus HA-specific T cell responses that showed low cross-reactivity with the H5 HA. We confirmed this observation by T cell cloning and identified a novel HA-specific epitope. However, we did not find any evidence that pre-existing T cells prevented pLAIV replication and take. CONCLUSION: We found that cross-reactive T cell responses could be boosted by pLAIV regardless of the induction of antibody. The impact of the "original antigenic sin" phenomenon in a subset of volunteers, with preferential expansion of seasonal influenza-specific but not H5N1-specific T cell responses merits further investigation.

Wang L, Xu K, Dong T, Rowland-Jones SL, Yindom LM. 2015. KIR3DS1*0130111: A novel KIR allele identified using molecular typing methods Tissue Antigens, 85 (4), pp. 296-297. | Show Abstract | Read more

© 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd. KIR3DS1*0130111 differs from KIR3DS1*0130101 with two previously undescribed single nucleotide polymorphisms.

Wang L, Yindom LM, Zhang Y, Xu K, Yan H, Dong T, Rowland-Jones SL. 2014. Killer-cell immunoglobulin-like receptor (KIR) genetic diversity in a unique HIV-1 cohort in China IMMUNOLOGY, 143 pp. 157-157.

Yindom LM, Wang L, Dong T, Rowland-Jones SL. 2014. Full length KIR3DS1*0130110 allele isolated by SBT Tissue Antigens, 84 (4), pp. 423-424. | Show Abstract | Read more

© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd. KIR3DS1*0130110 differs from KIR3DS1*0130101 with two nucleotide substitutions at positions 7322 (G > T) and 12617 (C > A), respectively.

Yindom L-M, Wang L, Dong T, Rowland-Jones SL. 2014. Full length KIR3DS1*0130110 allele isolated by SBT. Tissue Antigens, 84 (4), pp. 423-424. | Show Abstract | Read more

KIR3DS1*0130110 differs from KIR3DS1*0130101 with two nucleotide substitutions at positions 7322 (G > T) and 12617 (C > A), respectively.

Yindom L-M, Wang L, Zhang Y, Rowland-Jones SL, Dong T. 2014. KIR3DS1*0130108 isolated using full length sequence-based typing. Tissue Antigens, 84 (2), pp. 251-252. | Show Abstract | Read more

KIR3DS1*0130108 possesses three SNPs at: 12548C>G, 13804C>G and 13819G>A (introns 6 and 7, respectively) compared to KIR3DS1*0130101. © 2014 John Wiley & Sons A/S.

Yindom L-M, Wang L, Rai MA, Dong T, Rowland-Jones SL. 2014. Report of a novel activating killer-cell immunoglobulin-like receptor allele 3DS1*078 identified using sequence-based typing. Tissue Antigens, 84 (2), pp. 252-254. | Show Abstract | Read more

KIR3DS1*078 differs from KIR3DS1*0130101 at position 5586 and at position 14255. © 2014 John Wiley & Sons A/S.

Wang L, Xu K, Dong T, Rowland-Jones SL, Yindom LM. 2014. Identification of KIR3DL1*0150208 using long-range sequence-based techniques Tissue Antigens, 83 (5), pp. 372-373. | Show Abstract | Read more

KIR3DL1*0150208 possesses five point mutations: 3037G > A, 4115A > G, 6053G > C, 8034A > G, and 9446T > C compared to KIR3DL1*0150201. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Dang S, Gao N, Li Y, Li M, Wang X, Jia X, Zhai S, Zhang X, Liu J, Deng H, Dong T. 2014. Dominant CD4-dependent RNA-dependent RNA polymerase-specific T-cell responses in children acutely infected with human enterovirus 71 and healthy adult controls. Immunology, 142 (1), pp. 89-100. | Show Abstract | Read more

Human enterovirus 71 (EV71) is one of the major causes of hand, foot and mouth disease (HFMD), which leads to significant mortality in infected children. A prophylactic vaccine is urgently needed. However, little is known about the protective T-cell immunity in individuals infected with the EV71 virus. In this study, we performed a comprehensive ex vivo interferon-γ ELISPOT analysis in 31 children infected with EV71 as well as in 40 healthy adult controls of the CD4(+) and CD8(+) T-cell responses to overlapping peptides spanning the VP1 structural protein and RNA-dependent RNA polymerase (RdRp) non-structural protein. EV71-specific CD4 T-cell responses were detected in most of the acute patients and were mostly CD4-dependent RdRp-specific responses. CD8-dependent VP1 and RdRp-specific responses were also detected in a small proportion of recently infected children. There was no significant association between the strength of the T-cell responses and disease severity observed during the acute EV71 infection phase. Interestingly, an RdRp-specific, but no VP1-specific, CD4-dependent T-cell response was detected in 30% of the adult controls, and no T-cell responses were detected in healthy children. In addition, 24 individual peptides containing potential T-cell epitope regions were identified. The data suggest that CD4-dependent RdRp-specific T-cell responses may play an important role in protective immunity, and the epitopes identified in this study should provide valuable information for future therapeutic and prophylactic vaccine design as well as basic research.

Wang L, Zhang YH, Dong T, Rowland-Jones SL, Yindom LM. 2014. A novel full-length KIR3DS1*0130106 allele identified by sequencing Tissue Antigens, 83 (5), pp. 371-372. | Show Abstract | Read more

The novel KIR3DS1*0130106 differs from KIR3DS1*0130101 with a single point mutation at position 7211 (G > T). © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Yindom L-M, Wang L, Xu K, Dong T, Rowland-Jones SL. 2014. A novel KIR3DS1*0130107 allele isolated by sequencing from an Asian donor. Int J Immunogenet, 41 (3), pp. 267-268. | Show Abstract | Read more

This novel KIR3DS1 allele officially named as KIR3DS1*0130107 was isolated from DNA samples from Asia using high-resolution sequenced-based techniques. KIR3DS1*0130107 differs from the first member of the KIR3DS1*013 subgroup (KIR3DS1*0130101) by a single mutation at position 8922A>G (intron 5), just nine nucleotides away from the start of exon 6.

Wang L, Yindom LM, Rowland-Jones SL, Dong T. 2014. Identification of the KIR3DL1*0050105 allele by sequence-based techniques Tissue Antigens, 83 (4), pp. 301-302. | Show Abstract | Read more

KIR3DL1*0050105 differs from KIR3DL1*0050101 with two nucleotide substitutions at 6709(C > T) and 13398 (G > A) in introns 5 and 7, respectively. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Wang L, Yan H, Dong T, Rowland-Jones SL, Yindom LM. 2014. Detection of a novel killer-cell immunoglobulin-like receptor allele - KIR3DL1*0150207 - in Asian individuals Tissue Antigens, 83 (4), pp. 304-305. | Show Abstract | Read more

KIR3DL1*0150207 differs from KIR3DL1*0150201 at five nucleotide positions in introns 2, 3, 4 and 5, respectively. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Wang L, Xu K, Dong T, Rowland-Jones SL, Yindom L-M. 2014. Identification of KIR3DL1*0150208 using long-range sequence-based techniques. Tissue Antigens, 83 (5), pp. 372-373. | Show Abstract | Read more

KIR3DL1*0150208 possesses five point mutations: 3037G>A, 4115A>G, 6053G>C, 8034A>G, and 9446T>C compared to KIR3DL1*0150201. © 2014 John Wiley & Sons A/S.

Wang L, Zhang YH, Dong T, Rowland-Jones SL, Yindom L-M. 2014. A novel full-length KIR3DS1*0130106 allele identified by sequencing. Tissue Antigens, 83 (5), pp. 371-372. | Read more

Yindom LM, Wang L, Rowland-Jones SL, Dong T. 2014. Killer-cell immunoglobulin-like receptor gene 3DL1*077 isolated using long-range sequence-based techniques Tissue Antigens, 83 (3), pp. 206-207. | Show Abstract | Read more

KIR3DL1*077 gene has two non-synonymous mutations (exon 5) and six intronic changes compared to KIR3DL1*0150201. © 2014 John Wiley & Sons A/S.

Yindom LM, Wang L, Dong T, Rowland-Jones SL. 2014. A novel KIR3DL1*0070104 allele found in individuals from Asia Tissue Antigens, 83 (3), pp. 204-206. | Show Abstract | Read more

KIR3DL1*0070104 differs from KIR3DL1*0070101 at position 13889 (T > G) in the 3′UTR region of KIR3DL1/S1 locus. © 2014 John Wiley & Sons A/S.

Wang R, Hu Y, Yindom LM, Huang L, Wu R, Wang D, Chang C, Rostron T, Dong T, Wang X. 2014. Association analysis between HLA-A, -B, -C, -DRB1, and -DQB1 with nasopharyngeal carcinoma among a Han population in Northwestern China Human Immunology, 75 (3), pp. 197-202. | Show Abstract | Read more

Background: Most HLA association studies with NPC focus on Southern part of China. Thus, little is known about the genetic association of HLA with NPC in people from Northern China where the genetic background, environmental factors, and lifestyle are very different. Methods: 132 NPC patients and 168 normal controls of Han ethnic in Xinjiang Province were genotyped for HLA-A, -B, -C, -DRB1, and -DQB1 using the PCR-sequence specific primer technique. Results: Our results confirm previous findings that the HLA-B*46 and HLA-A * 02B * 46 haplotypes are strongly associated with NPC, but we did not observe HLA-A * 11 and -B * 35 association with resistance to NPC. Instead, we found that HLA-B * 51 and -A * 30 are strongly associated with resistance to NPC. In addition, HLA-A * 24 was also strongly associated with susceptibility to NPC. Conclusion: A unique pattern of HLA association with NPC susceptibility and resistance was found in patients from Xinjiang Province compared to the published data based on patients from Southern China and Taiwan. HLA-B * 46 is most significantly associated with NPC, and its frequency in endemic areas such as Guangdong Province, Taiwan, and Thailand is much higher than in Xinjiang Province and other areas with much less NPC occurrence. Interestingly, HLA-A * 30 is in contrast with the resistant allele, whose frequency is much lower in endemic areas but higher in Xinjiang and other areas with little NPC. © 2013 American Society for Histocompatibility and Immunogenetics.

Wang L, Yan H, Dong T, Rowland-Jones SL, Yindom L-M. 2014. Detection of a novel killer-cell immunoglobulin-like receptor allele - KIR3DL1*0150207 - in Asian individuals. Tissue Antigens, 83 (4), pp. 304-305. | Show Abstract | Read more

KIR3DL1*0150207 differs from KIR3DL1*0150201 at five nucleotide positions in introns 2, 3, 4 and 5, respectively.

Yindom L-M, Wang L, Dong T, Rowland-Jones SL, Zhang Y. 2014. The KIR3DS1*0130105 allele identified using high-resolution sequence-based typing. Tissue Antigens, 83 (4), pp. 302-303. | Show Abstract | Read more

KIR3DS1*0130105 allele differs from KIR3DS1*0130101 with a single mutation at position 6739G>T of intron 5.

Yindom LM, Wang L, Rowland-Jones SL, Dong T. 2014. Two novel KIR3DL1 alleles, 3DL1*0150205 and 3DL1*0150206, identified by full-length DNA sequencing Tissue Antigens, 83 (2), pp. 128-129. | Show Abstract | Read more

KIR3DL1*0150205 and KIR3DL1*0150206 alleles have five and six mutations, respectively, compared with KIR3DL1*0150201. © 2014 John Wiley & Sons A/S.

Yindom LM, Wang L, Okala SG, Dong T, Rowland-Jones SL. 2014. Report of a novel KIR3DS1*0130104 allele discovered using advanced molecular techniques Tissue Antigens, 83 (2), pp. 121-122. | Show Abstract | Read more

KIR3DS1*0130104 is identical to KIR3DS1*0130101 except for changes at positions 1768 (C > T) and 12617 (C > A). © 2014 John Wiley & Sons A/S.

Yindom LM, Wang L, Dong T, Rowland-Jones SL. 2014. Long-range sequencing revealed a new KIR3DL1*0150204 allele in 20 individuals of Asian descent Tissue Antigens, 83 (2), pp. 123-124. | Show Abstract | Read more

The novel KIR3DL1*0150204 has four point mutations: 3037G > A, 4115A > G, 6053G > C, and 8034A > G compared to KIR3DL1*0150201. © 2014 John Wiley & Sons A/S.

Yindom LM, Wang L, Dong T, Rowland-Jones SL. 2014. Identification of KIR3DL1*0200101 by long-range sequence-based techniques Tissue Antigens, 83 (2), pp. 127-128. | Show Abstract | Read more

The new KIR3DL1*0200101 differs from KIR3DL1*01502 with 12 single nucleotide polymorphisms (SNPs) in two exons and seven introns. © 2014 John Wiley & Sons A/S.

Yindom LM, Wang L, Dong T, Rowland-Jones SL. 2014. Description of a novel KIR3DL1*0050104 allele identified using sequence-based techniques Tissue Antigens, 83 (2), pp. 124-125. | Show Abstract | Read more

KIR3DL1*0050104 allele differs from KIR3DL1*0050101 at nucleotide positions 6709C > T (intron 5) and 11365A > G (intron 6). © 2014 John Wiley & Sons A/S.

Pan X, Huang LC, Dong T, Peng Y, Cerundolo V, McGowan S, Ogg G. 2014. Combinatorial HLA-peptide bead libraries for high throughput identification of CD8+ T cell specificity Journal of Immunological Methods, 403 (1-2), pp. 72-78. | Show Abstract | Read more

Comprehensive antigenic characterization of a T cell population of unknown specificity is challenging. Existing MHC class I expression systems are limited by the practical difficulty of probing cell populations with an MHC class I peptide library and the cross-reactivity of T cells that are able to recognise many variants of an index peptide. Using emulsion PCR and emulsion in vitro transcription/translation of a random library of peptides conjugated to CD8-null HLA-A*0201 on beads, we probed HLA-A*0201-restricted T cells with specificity for influenza, CMV and EBV. We observed significant enrichment for sequences containing HLA-A2 anchors and correct viral fragments for all T cell populations. HLA bead display provides a novel approach to identify the specificity of T cells. © 2013 Elsevier B.V.

Wang L, Yindom L-M, Rowland-Jones SL, Dong T. 2014. Identification of the KIR3DL1*0050105 allele by sequence-based techniques. Tissue Antigens, 83 (4), pp. 301-302. | Show Abstract | Read more

KIR3DL1*0050105 differs from KIR3DL1*0050101 with two nucleotide substitutions at 6709(C > T) and 13398 (G > A) in introns 5 and 7, respectively.

Yindom L-M, Wang L, Rowland-Jones SL, Dong T. 2014. Killer-cell immunoglobulin-like receptor gene 3DL1*077 isolated using long-range sequence-based techniques. Tissue Antigens, 83 (3), pp. 206-207. | Show Abstract | Read more

KIR3DL1*077 gene has two non-synonymous mutations (exon 5) and six intronic changes compared to KIR3DL1*0150201.

Yindom L-M, Wang L, Dong T, Rowland-Jones SL. 2014. A novel KIR3DL1*0070104 allele found in individuals from Asia. Tissue Antigens, 83 (3), pp. 204-206. | Show Abstract | Read more

KIR3DL1*0070104 differs from KIR3DL1*0070101 at position 13889 (T > G) in the 3'UTR region of KIR3DL1/S1 locus.

Yindom LM, Wang L, Rai MA, Dong T, Rowland-Jones SL. 2014. Report of a novel activating killer-cell immunoglobulin-like receptor allele 3DS1*078 identified using sequence-based typing Tissue Antigens, 84 (2), pp. 252-254. | Show Abstract | Read more

KIR3DS1*078 differs from KIR3DS1*0130101 at position 5586 and at position 14255. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Yindom LM, Wang L, Zhang Y, Rowland-Jones SL, Dong T. 2014. KIR3DS1*0130108 isolated using full length sequence-based typing Tissue Antigens, 84 (2), pp. 251-252. | Show Abstract | Read more

KIR3DS1*0130108 possesses three SNPs at: 12548C > G, 13804C > G and 13819G > A (introns 6 and 7, respectively) compared to KIR3DS1*0130101. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Wang R, Hu Y, Yindom L-M, Huang L, Wu R, Wang D, Chang C, Rostron T, Dong T, Wang X. 2014. Association analysis between HLA-A, -B, -C, -DRB1, and -DQB1 with nasopharyngeal carcinoma among a Han population in Northwestern China. Hum Immunol, 75 (3), pp. 197-202. | Show Abstract | Read more

BACKGROUND: Most HLA association studies with NPC focus on Southern part of China. Thus, little is known about the genetic association of HLA with NPC in people from Northern China where the genetic background, environmental factors, and lifestyle are very different. METHODS: 132 NPC patients and 168 normal controls of Han ethnic in Xinjiang Province were genotyped for HLA-A, -B, -C, -DRB1, and -DQB1 using the PCR-sequence specific primer technique. RESULTS: Our results confirm previous findings that the HLA-B∗46 and HLA-A(∗)02B(∗)46 haplotypes are strongly associated with NPC, but we did not observe HLA-A(∗)11 and -B(∗)35 association with resistance to NPC. Instead, we found that HLA-B(∗)51 and -A(∗)30 are strongly associated with resistance to NPC. In addition, HLA-A(∗)24 was also strongly associated with susceptibility to NPC. CONCLUSION: A unique pattern of HLA association with NPC susceptibility and resistance was found in patients from Xinjiang Province compared to the published data based on patients from Southern China and Taiwan. HLA-B(∗)46 is most significantly associated with NPC, and its frequency in endemic areas such as Guangdong Province, Taiwan, and Thailand is much higher than in Xinjiang Province and other areas with much less NPC occurrence. Interestingly, HLA-A(∗)30 is in contrast with the resistant allele, whose frequency is much lower in endemic areas but higher in Xinjiang and other areas with little NPC.

Pan X, Huang L-C, Dong T, Peng Y, Cerundolo V, McGowan S, Ogg G. 2014. Combinatorial HLA-peptide bead libraries for high throughput identification of CD8⁺ T cell specificity. J Immunol Methods, 403 (1-2), pp. 72-78. | Show Abstract | Read more

Comprehensive antigenic characterization of a T cell population of unknown specificity is challenging. Existing MHC class I expression systems are limited by the practical difficulty of probing cell populations with an MHC class I peptide library and the cross-reactivity of T cells that are able to recognise many variants of an index peptide. Using emulsion PCR and emulsion in vitro transcription/translation of a random library of peptides conjugated to CD8-null HLA-A*0201 on beads, we probed HLA-A*0201-restricted T cells with specificity for influenza, CMV and EBV. We observed significant enrichment for sequences containing HLA-A2 anchors and correct viral fragments for all T cell populations. HLA bead display provides a novel approach to identify the specificity of T cells.

Yindom LM, Wang L, Dong T, Rowland-Jones SL. 2013. Identification of KIR3DL1*0050103 by the sequence-based techniques Tissue Antigens, 82 (6), pp. 444-445. | Show Abstract | Read more

The new KIR3DL1*0050103 allele has a mutation at nucleotide position 6709 (C > T) in intron 5. © 2013 John Wiley & Sons A/S.

Yindom LM, Wang L, Rowland-Jones SL, Dong T. 2013. A novel full length KIR3DL1*0070103 identified by molecular typing Tissue Antigens, 82 (6), pp. 445-446. | Show Abstract | Read more

KIR3DL1*0070103 differs from KIR3DL1*0070101 with two mutations at 11548 * and 13889 (T > G), respectively. © 2013 John Wiley & Sons A/S.

Yindom LM, Wang L, Dong T, Rowland-Jones SL. 2014. Full-length genomic sequence of a new KIR3DL1*0150203 allele Tissue Antigens, 83 (2), pp. 122-123. | Show Abstract | Read more

KIR3DL1*0150203 allele differs from KIR3DL1*0150201 at 3037G > A, 4115A > G, 6053G > C, 8034A > G, 10723C > A, and 10747C > G. © 2014 John Wiley & Sons A/S.

Yindom L-M, Wang L, Dong T, Rowland-Jones SL. 2014. Full-length genomic sequence of a new KIR3DL1*0150203 allele. Tissue Antigens, 83 (2), pp. 122-123. | Show Abstract | Read more

KIR3DL1*0150203 allele differs from KIR3DL1*0150201 at 3037G>A, 4115A>G, 6053G>C, 8034A>G, 10723C>A, and 10747C>G.

Yindom L-M, Wang L, Dong T, Rowland-Jones SL. 2014. Long-range sequencing revealed a new KIR3DL1*0150204 allele in 20 individuals of Asian descent. Tissue Antigens, 83 (2), pp. 123-124. | Show Abstract | Read more

The novel KIR3DL1*0150204 has four point mutations: 3037G>A, 4115A>G, 6053G>C, and 8034A>G compared to KIR3DL1*0150201.

Yindom L-M, Wang L, Rowland-Jones SL, Dong T. 2014. Two novel KIR3DL1 alleles, 3DL1*0150205 and 3DL1*0150206, identified by full-length DNA sequencing. Tissue Antigens, 83 (2), pp. 128-129. | Show Abstract | Read more

KIR3DL1*0150205 and KIR3DL1*0150206 alleles have five and six mutations, respectively, compared with KIR3DL1*0150201.

Rai MA, Zhang Y, Yindom LM, Holmes J, Yu LM, Hao C, Rostron T, Yan H, Zhang YL, Cai C et al. 2013. HLA correlates in a cohort of slow progressors from China: Effects on HIV-1 disease progression AIDS, 27 (17), pp. 2822-2824. | Show Abstract | Read more

We looked at our HIVRslow progressors cohort to determine if there were any human leukocyte antigen (HLA) correlates for protection. No statistically significant allelic differences were found between the HIVRand control cohorts using regression analysis, though trendswere noted. Data for Elite Controllers showed an increased frequency of BM57. Likewise, no correlation was inferred with the clinical data of the HIVRcohort. We hypothesize that the protective effect of HLA alleles may have been lost over time. © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins.

Chen L, Fischer R, Peng Y, Reeves E, McHugh K, Ternette N, Hanke T, Dong T, Elliott T, Shastri N et al. 2014. Critical role of endoplasmic reticulum aminopeptidase 1 in determining the length and sequence of peptides bound and presented by HLA-B27. Arthritis Rheumatol, 66 (2), pp. 284-294. | Show Abstract | Read more

OBJECTIVE: HLA-B27 and endoplasmic reticulum aminopeptidase 1 (ERAP1) are the two strongest genetic factors predisposing to ankylosing spondylitis (AS). A key aminopeptidase in class I major histocompatibility complex presentation, ERAP1 potentially contributes to the pathogenesis of AS by altering HLA-B27 peptide presentation. The aim of this study was to analyze the effects of ERAP1 on the HLA-B27 peptide repertoire and peptide presentation to cytotoxic T lymphocytes (CTLs). METHODS: ERAP1-silenced and -competent HeLa.B27 and C1R.B27 cells were isotope-labeled, mixed, lysed, and then immunoprecipitated using W6/32 or ME1 antibodies. Peptides bound to HLA-B27 were eluted and analyzed by tandem mass spectrometry. Selected peptides were synthesized and tested for HLA-B27 binding ability. The effect of ERAP1 silencing/mutation on presentation of an immunodominant viral HLA-B27 epitope, KK10, to CTLs was also studied. RESULTS: In both HeLa.B27 and C1R.B27 cells, the proportion of 9-mer HLA-B27-bound peptides was decreased by ERAP1 silencing, whereas the percentages of longer peptides (11-13 mer) were increased. Surprisingly, following ERAP1 silencing, C-terminally extended peptides were readily identified. These were better able to bind to HLA-B27 than were N-terminally extended peptides lacking an arginine at position 2. In both HeLa.B27 cells and mouse fibroblasts expressing HLA-B27, the absence of ERAP1 reduced peptide recognition by HLA-B27-restricted KK10-specific CTLs following infection with recombinant vaccinia virus or transfection with minigenes expressing KK10 precursors. Presence of an AS-protective variant of ERAP1, K528R, as compared to wild-type ERAP1, reduced the peptide recognition by KK10 CTLs following transfection with extended KK10 minigenes. CONCLUSION: These results show that ERAP1 directly alters peptide binding and presentation by HLA-B27, thus demonstrating a potential pathogenic mechanism in AS. Inhibition of ERAP1 could potentially be used for treatment of AS and other ERAP1-associated diseases.

Yindom L-M, Wang L, Dong T, Rowland-Jones SL. 2013. Identification of KIR3DL1*0050103 by the sequence-based techniques. Tissue Antigens, 82 (6), pp. 444-445. | Show Abstract | Read more

The new KIR3DL1*0050103 allele has a mutation at nucleotide position 6709 (C>T) in intron 5. © 2013 John Wiley & Sons A/S.

Yindom L-M, Wang L, Rowland-Jones SL, Dong T. 2013. A novel full length KIR3DL1*0070103 identified by molecular typing. Tissue Antigens, 82 (6), pp. 445-446. | Show Abstract | Read more

KIR3DL1*0070103 differs from KIR3DL1*0070101 with two mutations at 11548 (G>A) and 13889 (T>G), respectively. © 2013 John Wiley & Sons A/S.

de Silva T, Peng Y, Leligdowicz A, Zaidi I, Li L, Griffin H, Blais M-E, Vincent T, Saraiva M, Yindom L-M et al. 2013. THE ROLE OF CD8+T-CELL RESPONSES IN THE PATHOGENESIS OF HIV-2, A NATURALLY CONTAINED HUMAN RETROVIRAL INFECTION JOURNAL OF INFECTION, 67 (4), pp. 344-344. | Read more

Rai MA, Zhang Y, Yindom L-M, Holmes J, Yu L-M, Hao C, Rostron T, Yan H, Zhang YL, Cai C et al. 2013. HLA correlates in a cohort of slow progressors from China: effects on HIV-1 disease progression. AIDS, 27 (17), pp. 2822-2824. | Show Abstract | Read more

We looked at our HIV + slow progressors cohort to determine if there were any human leukocyte antigen (HLA) correlates for protection. No statistically significant allelic differences were found between the HIV + and control cohorts using regression analysis, though trends were noted. Data for Elite Controllers showed an increased frequency of B*57. Likewise, no correlation was inferred with the clinical data of the HIV + cohort. We hypothesize that the protective effect of HLA alleles may have been lost over time.

Alexander N, Fox A, Lien VTK, Dong T, Lee LY-H, Hang NLK, Mai LQ, Horby P. 2013. Defining ELISpot cut-offs from unreplicated test and control wells JOURNAL OF IMMUNOLOGICAL METHODS, 392 (1-2), pp. 57-62. | Show Abstract | Read more

In the absence of replication of wells, empirical criteria for enzyme-linked immunospot (ELISpot) positivity use fixed differences or ratios between spot forming units (SFU) counts between test and control. We propose an alternative approach which first identifies the optimally variance-stabilizing transformation of the SFU counts, based on the Bland-Altman plot of the test and control wells. The second step is to derive a positivity threshold from the difference in between-plate distribution functions of the transformed test and control SFU counts. This method is illustrated using 1309 assay results from a cohort study of influenza in Vietnam in which some, but not all, of the peptide pools have clear tendencies for SFU counts to be higher in test than control wells. © 2013 Elsevier B.V.

de Silva TI, Peng Y, Leligdowicz A, Zaidi I, Li L, Griffin H, Blais M-E, Vincent T, Saraiva M, Yindom L-M et al. 2013. Correlates of T-cell-mediated viral control and phenotype of CD8(+) T cells in HIV-2, a naturally contained human retroviral infection. Blood, 121 (21), pp. 4330-4339. | Show Abstract | Read more

While a significant proportion of HIV-2-infected individuals are asymptomatic and maintain undetectable viral loads (controllers), 15% to 20% progress to AIDS and are predicted by detectable viremia. Identifying immune correlates that distinguish these 2 groups should provide insights into how a potentially pathogenic retrovirus can be naturally controlled. We performed a detailed study of HIV-2-specific cellular responses in a unique community cohort in Guinea-Bissau followed for over 2 decades. T-cell responses were compared between controllers (n = 33) and viremic subjects (n = 27) using overlapping peptides, major histocompatibility complex class I tetramers, and multiparameter flow cytometry. HIV-2 viral control was significantly associated with a high-magnitude, polyfunctional Gag-specific CD8(+) T-cell response but not with greater perforin upregulation. This potentially protective HIV-2-specific response is surprisingly narrow. HIV-2 Gag-specific CD8(+) T cells are at an earlier stage of differentiation than cytomegalovirus-specific CD8(+) T-cells, do not contain high levels of cytolytic markers, and exhibit low levels of activation and proliferation, representing distinct properties from CD8(+) T cells associated with HIV-1 control. These data reveal the potential T-cell correlates of HIV-2 control and the detailed phenotype of virus-specific CD8(+) T cells in a naturally contained retroviral infection.

Rai MA, Zhang Y-H, Yan H-P, Zhao Y, Abidi SH, Qu W-Y, McMichael A, Dong T, Rowland-Jones S, Xu K-Y. 2013. Immune selection and vpu variability in a unique narrow source HIV-Positive village cohort JAIDS-JOURNAL OF ACQUIRED IMMUNE DEFICIENCY SYNDROMES, 62 pp. 69-69.

Zhang Y-H, Zhao Y, Li N, Peng Y-C, Giannoulatou E, Jin R-H, Yan H-P, Wu H, Liu J-H, Liu N et al. 2013. Interferon-induced transmembrane protein-3 genetic variant rs12252-C is associated with severe influenza in Chinese individuals. Nat Commun, 4 pp. 1418. | Show Abstract | Read more

The SNP rs12252-C allele alters the function of interferon-induced transmembrane protein-3 increasing the disease severity of influenza virus infection in Caucasians, but the allele is rare. However, rs12252-C is much more common in Han Chinese. Here we report that the CC genotype is found in 69% of Chinese patients with severe pandemic influenza A H1N1/09 virus infection compared with 25% in those with mild infection. Specifically, the CC genotype was estimated to confer a sixfold greater risk for severe infection than the CT and TT genotypes. More importantly, because the risk genotype occurs with such a high frequency, its effect translates to a large population-attributable risk of 54.3% for severe infection in the Chinese population studied compared with 5.4% in Northern Europeans. Interferon-induced transmembrane protein-3 genetic variants could, therefore, have a strong effect of the epidemiology of influenza in China and in people of Chinese descent.

Yindom L-M, Wang L, Dong T, Rowland-Jones SL. 2014. Identification of KIR3DL1*0200101 by long-range sequence-based techniques. Tissue Antigens, 83 (2), pp. 127-128. | Show Abstract | Read more

The new KIR3DL1*0200101 differs from KIR3DL1*01502 with 12 single nucleotide polymorphisms (SNPs) in two exons and seven introns.

Yindom L-M, Wang L, Dong T, Rowland-Jones SL. 2014. Description of a novel KIR3DL1*0050104 allele identified using sequence-based techniques. Tissue Antigens, 83 (2), pp. 124-125. | Show Abstract | Read more

KIR3DL1*0050104 allele differs from KIR3DL1*0050101 at nucleotide positions 6709C>T (intron 5) and 11365A>G (intron 6).

Yindom L-M, Wang L, Okala SG, Dong T, Rowland-Jones SL. 2014. Report of a novel KIR3DS1*0130104 allele discovered using advanced molecular techniques. Tissue Antigens, 83 (2), pp. 121-122. | Show Abstract | Read more

KIR3DS1*0130104 is identical to KIR3DS1*0130101 except for changes at positions 1768 (C>T) and 12617 (C>A).

Madsen J, Gaiha GD, Palaniyar N, Dong T, Mitchell DA, Clark HW. 2013. Can Surfactant Protein D Inhibit HIV Infection in the Lung? NEONATOLOGY, 103 (4), pp. 347-347.

Powell TJ, Peng Y, Berthoud TK, Blais M-E, Lillie PJ, Hill AVS, Rowland-Jones SL, McMichael AJ, Gilbert SC, Dong T. 2013. Examination of influenza specific T cell responses after influenza virus challenge in individuals vaccinated with MVA-NP+M1 vaccine. PLoS One, 8 (5), pp. e62778. | Show Abstract | Read more

Current influenza vaccines stimulate neutralising antibody to the haemagglutinin antigen but as there is antigenic drift in HA it is difficult to prepare a vaccine in advance against an emergent strain. A potential strategy is to induce CD8(+) and CD4(+) T cells that recognize epitopes within internal proteins that are less subject to antigenic drift. Augmenting humoral responses to HA with T cell responses to more conserved antigens may result in a more broadly protective vaccine. In this study, we evaluate the quality of influenza specific T cell responses in a clinical trial using MVA-NP+M1 vaccination followed by influenza virus challenge. In vaccinated volunteers, the expression of Granzyme A, Perforin and CD57 on influenza HLA A*02 M158-66 antigen specific cells was higher than non-vaccinated volunteers before and after challenge despite a similar frequency of antigen specific cells. BCL2 expression was lower in vaccinated volunteers. These data indicate that antigen specific T cells are a useful additional measure for use in human vaccination or immunization studies.

Madsen J, Gaiha GD, Palaniyar N, Dong T, Mitchell DA, Clark HW. 2013. Surfactant Protein D modulates HIV infection of both T-cells and dendritic cells. PLoS One, 8 (3), pp. e59047. | Show Abstract | Read more

Surfactant Protein D (SP-D) is an oligomerized C-type lectin molecule with immunomodulatory properties and involvement in lung surfactant homeostasis in the respiratory tract. SP-D binds to the enveloped viruses, influenza A virus and respiratory syncytial virus and inhibits their replication in vitro and in vivo. SP-D has been shown to bind to HIV via the HIV envelope protein gp120 and inhibit infectivity in vitro. Here we show that SP-D binds to different strains of HIV (BaL and IIIB) and the binding occurs at both pH 7.4 and 5.0 resembling physiological relevant pH values found in the body and the female urogenital tract, respectively. The binding of SP-D to HIV particles and gp120 was inhibited by the presence of several hexoses with mannose found to be the strongest inhibitor. Competition studies showed that soluble CD4 and CVN did not interfere with the interaction between SP-D and gp120. However, soluble recombinant DC-SIGN was shown to inhibit the binding between SP-D and gp120. SP-D agglutinated HIV and gp120 in a calcium dependent manner. SP-D inhibited the infectivity of HIV strains at both pH values of 7.4 and 5.0 in a concentration dependent manner. The inhibition of the infectivity was abolished by the presence of mannose. SP-D enhanced the binding of HIV to immature monocyte derived dendritic cells (iMDDCs) and was also found to enhance HIV capture and transfer to the T-cell like line PM1. These results suggest that SP-D can bind to and inhibit direct infection of T-cells by HIV but also enhance the transfer of infectious HIV particles from DCs to T-cells in vivo.

Zhao Y, Zhang Y-H, Denney L, Young D, Powell TJ, Peng Y-C, Li N, Yan H-P, Wang D-Y, Shu Y-L et al. 2012. High levels of virus-specific CD4+ T cells predict severe pandemic influenza A virus infection. Am J Respir Crit Care Med, 186 (12), pp. 1292-1297. | Show Abstract | Read more

RATIONALE: T-cell responses have been implicated in control and exacerbation of lung injury during influenza A virus (IAV) infection. OBJECTIVES: To examine the breadth and magnitude of influenza-specific CD4(+) and CD8(+) T-cell responses during acute phase of infection. METHODS: Influenza-specific T-cell response to the entire pandemic H1N1/09 IAV proteome and T cell-related cytokine levels were measured in blood from previously healthy individuals with mild (n = 32) and severe (n = 16) IAV infection during the 2009 influenza pandemic. Virus-specific T-cell response in lung and blood was also performed in two acutely infected, severely ill patients using fluorescent-conjugated pdmH1N1/09 Matrix-MHC-I tetrameric complexes. MEASUREMENTS AND MAIN RESULTS: Strong and broad CD4(+) but not CD8(+) T-cell responses were observed in the blood, and were higher in those with severe disease. Antigen-specific CD8(+) T cells in the lungs were on average 45-fold higher compared with blood in severely ill patients. Paradoxically, in patients with severe disease, IL-17, IL-2, IL-4, and IFN-γ levels were significantly decreased. CONCLUSIONS: High levels of circulating virus-specific CD4(+) T cells to two viral internal proteins (nucleoprotein and matrix) in the first phase of infection are associated with subsequent development of severe IAV infection. This finding could be an early and specific marker for ensuing clinical deterioration. Contrasting levels of antigen-specific CD8(+) T cells in lungs and blood have implications on design and analysis of clinical trials for T-cell vaccines because measurements of T cells in the periphery may not reflect events in the lungs.

Slyker JA, Rowland-Jones SL, Dong T, Reilly M, Richardson B, Emery VC, Atzberger A, Mbori-Ngacha D, Lohman-Payne BL, John-Stewart GC. 2012. Acute cytomegalovirus infection is associated with increased frequencies of activated and apoptosis-vulnerable T cells in HIV-1-infected infants. J Virol, 86 (20), pp. 11373-11379. | Show Abstract | Read more

Cytomegalovirus (CMV) coinfection is associated with infant HIV-1 disease progression and mortality. In a cohort of Kenyan HIV-infected infants, the frequencies of activated (CD38(+) HLA-DR(+)) and apoptosis-vulnerable (CD95(+) Bcl-2(-)) CD4(+) and CD8(+) T cells increased substantially during acute CMV infection. The frequency of activated CD4(+) T cells was strongly associated with both concurrent CMV coinfection (P = 0.001) and HIV-1 viral load (P = 0.05). The frequency of apoptosis-vulnerable cells was also associated with CMV coinfection in the CD4 (P = 0.02) and CD8 (P < 0.001) T cell subsets. Similar observations were made in HIV-exposed uninfected infants. CMV-induced increases in T cell activation and apoptosis may contribute to the rapid disease progression in coinfected infants.

Rajapaksa US, Li D, Peng Y-C, McMichael AJ, Dong T, Xu X-N. 2012. HLA-B may be more protective against HIV-1 than HLA-A because it resists negative regulatory factor (Nef) mediated down-regulation. Proc Natl Acad Sci U S A, 109 (33), pp. 13353-13358. | Show Abstract | Read more

Human leukocyte antigen HLA-B alleles have better protective activity against HIV-1 than HLA-A alleles, possibly due to differences in HLA-restricted HIV-1-specific CD8+ cytotoxic T lymphocyte (CTL) function, but the mechanism is unknown. HIV-1 negative regulatory factor (Nef) mediates down-regulation of surface expression of class I HLA (HLA-I) and may therefore impair immune recognition by CTL. Because of sequence differences in the cytoplasmic domains, HLA-A and -B are down-regulated by Nef but HLA-C and -E are not affected. However, the latter are expressed at low levels and are not of major importance in the CTL responses to HIV-1. Here, we compared the role of the cytoplasmic domains of HLA-A and -B in Nef-mediated escape from CTL. We found HLA-B cytoplasmic domains were more resistant to Nef-mediated down-regulation than HLA-A cytoplasmic domains and demonstrated that these differences affect CTL recognition of virus-infected cells in vitro. We propose that the relative resistance to Nef-mediated down-regulation by the cytoplasmic domains of HLA-B compared with HLA-A contributes to the better control of HIV-1 infection associated with HLA-B-restricted CTLs.

Zhou D, Zhang X, Li W, Xu X, Goonetilleke N, Yang H, Dong T, Yan H. 2013. Short communication: broader T cell responses directed against human immunodeficiency virus type 1 in infected Chinese individuals through blood-borne transmission in comparison with mucosal transmission. AIDS Res Hum Retroviruses, 29 (1), pp. 89-93. | Show Abstract | Read more

Cellular immune responses play a critical role in the control of human immunodeficiency virus type 1 (HIV-1), but less is known about the impact of transmission routes on immune defenses against HIV-1. Here, we report that subjects infected with HIV-1 through contaminated blood showed stronger HIV-specific T cell responses than those infected through mucosa, both in breadth (6.9±2.5 vs. 2.3±0.5, p=0.0293) and in magnitude [1270.0±544.9 vs. 409.5±121.3 SFU per million peripheral blood mononuclear cells (PBMCs), p=0.0223], by using a matrix of 404 overlapping peptides spanning all expressed HIV-1 proteins in an interferon (IFN)-γ enzyme-linked immunospot (ELISpot) assay. Our observation indicates that different mechanisms might be involved in the priming/generating of anti-HIV-specific T cell responses through different transmission routes.

Blais M-E, Zhang Y, Rostron T, Griffin H, Taylor S, Xu K, Yan H, Wu H, James I, John M et al. 2012. High frequency of HIV mutations associated with HLA-C suggests enhanced HLA-C-restricted CTL selective pressure associated with an AIDS-protective polymorphism. J Immunol, 188 (9), pp. 4663-4670. | Show Abstract | Read more

Delayed HIV-1 disease progression is associated with a single nucleotide polymorphism upstream of the HLA-C gene that correlates with differential expression of the HLA-C Ag. This polymorphism was recently shown to be a marker for a protective variant in the 3'UTR of HLA-C that disrupts a microRNA binding site, resulting in enhanced HLA-C expression at the cell surface. Whether individuals with "high" HLA-C expression show a stronger HLA-C-restricted immune response exerting better viral control than that of their counterparts has not been established. We hypothesized that the magnitude of the HLA-C-restricted immune pressure on HIV would be greater in subjects with highly expressed HLA-C alleles. Using a cohort derived from a unique narrow source epidemic in China, we identified mutations in HIV proviral DNA exclusively associated with HLA-C, which were used as markers for the intensity of the immune pressure exerted on the virus. We found an increased frequency of mutations in individuals with highly expressed HLA-C alleles, which also correlated with IFN-γ production by HLA-C-restricted CD8(+) T cells. These findings show that immune pressure on HIV is stronger in subjects with the protective genotype and highlight the potential role of HLA-C-restricted responses in HIV control. This is, to our knowledge, the first in vivo evidence supporting the protective role of HLA-C-restricted responses in nonwhites during HIV infection.

Lillie PJ, Berthoud TK, Powell TJ, Lambe T, Mullarkey C, Spencer AJ, Hamill M, Peng Y, Blais M-E, Duncan CJA et al. 2012. Preliminary assessment of the efficacy of a T-cell-based influenza vaccine, MVA-NP+M1, in humans. Clin Infect Dis, 55 (1), pp. 19-25. | Show Abstract | Read more

BACKGROUND: The novel influenza vaccine MVA-NP+M1 is designed to boost cross-reactive T-cell responses to internal antigens of the influenza A virus that are conserved across all subtypes, providing protection against both influenza disease and virus shedding against all influenza A viruses. Following a phase 1 clinical study that demonstrated vaccine safety and immunogenicity, a phase 2a vaccination and influenza challenge study has been conducted in healthy adult volunteers. METHODS: Volunteers with no measurable serum antibodies to influenza A/Wisconsin/67/2005 received either a single vaccination with MVA-NP+M1 or no vaccination. T-cell responses to the vaccine antigens were measured at enrollment and again prior to virus challenge. All volunteers underwent intranasal administration of influenza A/Wisconsin/67/2005 while in a quarantine unit and were monitored for symptoms of influenza disease and virus shedding. RESULTS: Volunteers had a significantly increased T-cell response to the vaccine antigens following a single dose of the vaccine, with an increase in cytolytic effector molecules. Intranasal influenza challenge was undertaken without safety issues. Two of 11 vaccinees and 5 of 11 control subjects developed laboratory-confirmed influenza (symptoms plus virus shedding). Symptoms of influenza were less pronounced in the vaccinees and there was a significant reduction in the number of days of virus shedding in those vaccinees who developed influenza (mean, 1.09 days in controls, 0.45 days in vaccinees, P = .036). CONCLUSIONS: This study provides the first demonstration of clinical efficacy of a T-cell-based influenza vaccine and indicates that further clinical development should be undertaken. CLINICAL TRIALS REGISTRATION: NCT00993083.

Culshaw A, Dong T, Rowland-Jones SL. 2012. A 2 amino acid shift in position leads to a substantial difference in the pattern of processing of 2 HIV-1 epitopes. J Acquir Immune Defic Syndr, 59 (4), pp. 335-339. | Show Abstract | Read more

BACKGROUND: The sequence diversity that exists between HIV-1 strains presents a major obstacle to the design of a vaccine that will be effective on a global scale. Focusing on highly conserved cytotoxic T-lymphocyte epitopes as vaccine targets has been called into question by evidence that variation within epitope flanking regions can affect processing and presentation. METHODS: Using epitope-specific T-cell clones tested for recognition of HLA-matched target cells infected with vaccinia viruses expressing HIV-1 nef genes derived from different HIV-1 clades, we examined the efficiency of presentation of an HLA-B*40 restricted HIV-1 nef epitope compared to that of an HLA-B*08 restricted epitope with which it overlaps by 6 amino acides. RESULTS: This small shift in epitope position substantially changed the patter or epitope processing and led either to an increase or decrease in antigen generation dependent on the viral sequences present. CONCLUSIONS: These data demonstrate the complexity of the antigen presentation pathway and the difficulties associated with selecting CTL epitopes as targets for an HIV-1 vaccine that will be effective in many populations and against several viral strains.

Slyker JA, Lohman-Payne B, John-Stewart GC, Dong T, Mbori-Ngacha D, Tapia K, Atzberger A, Taylor S, Rowland-Jones SL, Blish CA. 2012. The impact of HIV-1 infection and exposure on natural killer (NK) cell phenotype in Kenyan infants during the first year of life. Front Immunol, 3 (DEC), pp. 399. | Show Abstract | Read more

Natural killer (NK) cells play an important role in the containment of HIV replication during primary infection, though their functions are impaired during chronic HIV infection. Infants experience more rapid HIV disease progression than adults, but contributions of infant NK cells to containing HIV infection are unknown. The aim of this study was to determine the impact of HIV infection on infant NK cell phenotype by evaluating samples and data from a cohort study of women and their infants, conducted in Nairobi, Kenya between 1999 and 2003. The percentage and phenotype of NK cells was evaluated longitudinally by multi-parameter flow cytometry over the first year of life in HIV-infected (HIV+, = 16), HIV-exposed uninfected (HIV-EU, n = 6), and healthy unexposed controls (HIV-, n = 4). At birth, NK subset distributions based on expression of CD56 and CD16 did not differ between HIV+, HIV-EU, or HIV- infants. However, HIV infection was associated with a subsequent decline in NK cells as a percentage of total lymphocytes (p < 0.001), and an expanding proportion of CD56-CD16+ NK cells (p < 0.001). Activated CD38(bright)CD69+ NK cells were more frequent in the HIV+ infants, followed by HIV-EU and HIV- infants, in both CD56(dim) (p = 0.005) and CD56(bright) compartments (p = 0.03). HIV infection and exposure was also associated with a significant decline in the percentage of perforin-expressing NK cells in the CD56(dim) compartment over the first year of life, with HIV+ infants losing approximately 2.5% (p < 0.001) and HIV-EU infants losing 3.0% (p = 0.01) of perforin+ cells per month. Thus, infant HIV infection is associated with alterations in NK cell subsets, activation, and cytolytic potential that could contribute to their poor control over HIV infection. Furthermore, exposure to HIV infection in infants who escaped infection is also associated with alterations in NK cells that may contribute to the reduced ability to fight infections that is observed in HIV-EU infants.

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Wilkinson TM, Li CKF, Chui CSC, Huang AKY, Perkins M, Liebner JC, Lambkin-Williams R, Gilbert A, Oxford J, Nicholas B et al. 2012. Preexisting influenza-specific CD4<sup>+</sup>T cells correlate with disease protection against influenza challenge in humans Nature Medicine, 18 (2), pp. 274-280. | Show Abstract | Read more

Protective immunity against influenza virus infection is mediated by neutralizing antibodies, but the precise role of T cells in human influenza immunity is uncertain. We conducted influenza infection studies in healthy volunteers with no detectable antibodies to the challenge viruses H3N2 or H1N1. We mapped T cell responses to influenza before and during infection. We found a large increase in influenza-specific T cell responses by day 7, when virus was completely cleared from nasal samples and serum antibodies were still undetectable. Preexisting CD4 + , but not CD8 + , T cells responding to influenza internal proteins were associated with lower virus shedding and less severe illness. These CD4 + cells also responded to pandemic H1N1 (A/CA/07/2009) peptides and showed evidence of cytotoxic activity. These cells are an important statistical correlate of homotypic and heterotypic response and may limit severity of influenza infection by new strains in the absence of specific antibody responses. Our results provide information that may aid the design of future vaccines against emerging influenza strains. © 2012 Nature America, Inc. All rights reserved. © 2012 Nature America, Inc. All rights reserved.

Wilkinson TM, Li CKF, Chui CSC, Huang AKY, Perkins M, Liebner JC, Lambkin-Williams R, Gilbert A, Oxford J, Nicholas B et al. 2012. Preexisting influenza-specific CD4+ T cells correlate with disease protection against influenza challenge in humans. Nat Med, 18 (2), pp. 274-280. | Show Abstract | Read more

Protective immunity against influenza virus infection is mediated by neutralizing antibodies, but the precise role of T cells in human influenza immunity is uncertain. We conducted influenza infection studies in healthy volunteers with no detectable antibodies to the challenge viruses H3N2 or H1N1. We mapped T cell responses to influenza before and during infection. We found a large increase in influenza-specific T cell responses by day 7, when virus was completely cleared from nasal samples and serum antibodies were still undetectable. Preexisting CD4+, but not CD8+, T cells responding to influenza internal proteins were associated with lower virus shedding and less severe illness. These CD4+ cells also responded to pandemic H1N1 (A/CA/07/2009) peptides and showed evidence of cytotoxic activity. These cells are an important statistical correlate of homotypic and heterotypic response and may limit severity of influenza infection by new strains in the absence of specific antibody responses. Our results provide information that may aid the design of future vaccines against emerging influenza strains.

Jayasooriya S, Hislop A, Peng Y, Croom-Carter D, Jankey Y, Bell A, Dong T, Rowland-Jones S, Rickinson A, Walther M, Whittle H. 2012. Revisiting the effect of acute P. falciparum malaria on Epstein-Barr virus: host balance in the setting of reduced malaria endemicity. PLoS One, 7 (2), pp. e31142. | Show Abstract | Read more

Burkitt's lymphoma (BL), an EBV-associated tumour, occurs at high incidence in populations where malaria is holoendemic. Previous studies in one such population suggested that acute P.falciparum infection impairs EBV-specific T-cell surveillance, allowing expansion of EBV infected B-cells from which BL derives. We re-examined the situation in the same area, The Gambia, after a reduction in malaria endemicity. Cellular immune responses to EBV were measured in children with uncomplicated malaria before (day 0) and after treatment (day 28), comparing EBV genome loads in blood and EBV-specific CD8(+) T-cell numbers (assayed by MHC Class I tetramers and IFNγ ELISPOTS) with those seen in age- and sex-matched healthy controls. No significant changes were seen in EBV genome loads, percentage of EBV-specific CD8(+) T-cells and IFNγ producing T-cells in acute versus convalescent samples, nor any difference versus controls. Regression assays performed also no longer detected any impairment of EBV-specific T-cell surveillance. Acute uncomplicated malaria infection no longer alters EBV-specific immune responses in children in The Gambia. Given the recent decline in malaria incidence in that country, we hypothesise that gross disturbance of the EBV-host balance may be a specific effect of acute malaria only in children with a history of chronic/recurrent malaria challenge.

Zhang Y, Liu Y, Zhao Y, Shi L, Ma L, Yan H, Wu H, Wei L, Dong T, Chen X. 2012. Hepatitis C virus nonstructural protein specific T cells are associated with virological responses to combination therapy in chronic HCV patients. Liver Int, 32 (1), pp. 102-109. | Show Abstract | Read more

BACKGROUND: Virus-specific T-cell responses play a major role in antiviral immune response. However, the effect of hepatitis C virus (HCV)-specific T-cell responses on combination therapy still remains controversial. AIMS: To identify the association between HCV-specific T cell responses and efficiency of combination therapy. METHODS: To address this issue, a longitudinal analysis of HCV-specific T-cell responses to overlapping peptides covering HCV-nonstructural protein (NS) was performed using ELISpot assay in 48 chronically infected HCV-1b patients during combination treatment with peginterferon-alfa and ribavirin. RESULTS: Fifty-two percent of chronic HCV patients showed detectable HCV-NS3, NS4 or NS5A specific T-cell responses before therapy, with NS3 appearing to be the most immunodominant protein followed by NS5A and NS4. In addition, the percentage of patients responding to peptide stimulation was higher in patients with sustained virological response (SVR) when compared with those without SVR. Dynamics of HCV-NS-specific T-cell responses were further analysed; we found that HCV-specific T-cell responses maintained higher levels at 12 weeks into treatment in patients with SVR. In contrast, HCV-specific T-cell responses in patients without SVR declined significantly at 4 weeks into treatment and maintained low levels at 12 weeks. CONCLUSION: We found that the HCV-specific T-cell responses were associated with good viral control in patients with combination therapy.

Powell TJ, Fox A, Peng Y, Quynh Mai LT, Lien VTK, Hang NLK, Wang L, Lee LY-H, Simmons CP, McMichael AJ et al. 2012. Identification of H5N1-specific T-cell responses in a high-risk cohort in vietnam indicates the existence of potential asymptomatic infections. J Infect Dis, 205 (1), pp. 20-27. | Show Abstract | Read more

BACKGROUND: Most reported human H5N1 viral infections have been severe and were detected after hospital admission. A case ascertainment bias may therefore exist, with mild cases or asymptomatic infections going undetected. We sought evidence of mild or asymptomatic H5N1 infection by examining H5N1-specific T-cell and antibody responses in a high-risk cohort in Vietnam. METHODS: Peripheral blood mononuclear cells were tested using interferon-γ enzyme-linked immunospot T assays measuring the response to peptides of influenza H5, H3, and H1 hemagglutinin (HA), N1 and N2 neuraminidase, and the internal proteins of H3N2. Horse erythrocyte hemagglutination inhibition assay was performed to detect antibodies against H5N1. RESULTS: Twenty-four of 747 individuals demonstrated H5-specific T-cell responses but little or no cross-reactivity with H3 or H1 HA peptides. H5N1 peptide-specific T-cell lines that did not cross-react with H1 or H3 influenza virus HA peptides were generated. Four individuals also had antibodies against H5N1. CONCLUSIONS: This is the first report of ex vivo H5 HA-specific T-cell responses in a healthy but H5N1-exposed population. Our results indicate that the presence of H5N1-specific T cells could be an additional diagnostic tool for asymptomatic H5N1 infection.

Germain C, Meier A, Jensen T, Knapnougel P, Poupon G, Lazzari A, Neisig A, Håkansson K, Dong T, Wagtmann N et al. 2011. Induction of lectin-like transcript 1 (LLT1) protein cell surface expression by pathogens and interferon-γ contributes to modulate immune responses. J Biol Chem, 286 (44), pp. 37964-37975. | Show Abstract | Read more

CD161 is a C-type lectin-like receptor expressed on human natural killer (NK) cells and subsets of T cells. CD161 has been described as an inhibitory receptor that regulates NK cell-mediated cytotoxicity and IFN-γ production. Its role on T cells has remained unclear. Studies have shown that triggering of CD161 enhances NK T cell proliferation and T cell-IFN-γ production while inhibiting TNF-α production by CD8(+) T cells. Lectin-like transcript 1 (LLT1), the ligand of CD161, was found to be expressed on Toll-like receptor (TLR)-activated plasmacytoid and monocyte-derived dendritic cells (DC) and on activated B cells. Using newly developed anti-LLT1 mAbs, we show that LLT1 is not expressed on the surface of circulating B and T lymphocytes, NK cells, monocytes, and dendritic cells but that LLT1 is up-regulated upon activation. Not only TLR-stimulated dendritic cells and B cells but also T cell receptor-activated T cells and activated NK cells up-regulate LLT1. Interestingly, IFN-γ increases LLT1 expression level on antigen-presenting cells. LLT1 is also induced on B cells upon viral infection such as Epstein-Barr virus or HIV infection and in inflamed tonsils. Finally, expression of LLT1 on B cells inhibits NK cell function but costimulates T cell proliferation or IFN-γ production, and coengagement of CD161 with CD3 increases IL-17 secretion. Altogether, our results point toward a role for LLT1/CD161 in modulating immune responses to pathogens.

Zhang Y, Peng Y, Yan H, Xu K, Saito M, Wu H, Chen X, Ranasinghe S, Kuse N, Powell T et al. 2011. Multilayered defense in HLA-B51-associated HIV viral control. J Immunol, 187 (2), pp. 684-691. | Show Abstract | Read more

Polymorphism in the HLA region of a chromosome is the major source of host genetic variability in HIV-1 outcome, but there is limited understanding of the mechanisms underlying the beneficial effect of protective class I alleles such as HLA-B57, -B27, and -B51. Taking advantage of a unique cohort infected with clade B' HIV-1 through contaminated blood, in which many variables such as the length of infection, the infecting viral strain, and host genetic background are controlled, we performed a comprehensive study to understand HLA-B51-associated HIV-1 control. We focused on the T cell responses against three dominant HLA-B51-restricted epitopes: Gag327-345(NI9) NANPDCKTI, Pol743-751(LI9) LPPVVAKEI, and Pol283-289(TI8) TAFTIPSI. Mutations in all three dominant epitopes were significantly associated with HLA-B51 in the cohort. A clear hierarchy in selection of epitope mutations was observed through epitope sequencing. L743I in position 1 of epitope LI9 was seen in most B51(+) individuals, followed by V289X in position 8 of the TI8, and then, A328S, in position 2 of the NI9 epitope, was also seen in some B51(+) individuals. Good control of viral load and higher CD4(+) counts were significantly associated with at least one detectable T cell response to unmutated epitopes, whereas lower CD4(+) counts and higher viral loads were observed in patients who had developed escape mutations in all three epitopes or who lacked T cell responses specific to these epitope(s). We propose that patients with HLA-B51 benefit from having multiple layers of effective defense against the development of immune escape mutations.

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Zhang Y, Peng Y, Yan H, Xu K, Saito M, Wu H, Chen X, Ranasinghe S, Kuse N, Powell T et al. 2011. Multilayered Defense in HLA-B51-Associated HIV Viral Control JOURNAL OF IMMUNOLOGY, 187 (2), pp. 684-691. | Show Abstract | Read more

Polymorphism in the HLA region of a chromosome is the major source of host genetic variability in HIV-1 outcome, but there is limited understanding of the mechanisms underlying the beneficial effect of protective class I alleles such as HLA-B57, -B27, and -B51. Taking advantage of a unique cohort infected with clade B' HIV-1 through contaminated blood, in which many variables such as the length of infection, the infecting viral strain, and host genetic background are controlled, we performed a comprehensive study to understand HLA-B51-associated HIV-1 control.We focused on the T cell responses against three dominant HLA-B51-restricted epitopes: Gag327-345(NI9) NANPDCKTI, Pol743-751(LI9) LPPVVAKEI, and Pol283-289(TI8) TAFTIPSI. Mutations in all three dominant epitopes were significantly associated with HLA-B51 in the cohort. A clear hierarchy in selection of epitope mutations was observed through epitope sequencing. L743I in position 1 of epitope LI9 was seen in most B51 + individuals, followed by V289X in position 8 of the TI8, and then, A328S, in position 2 of the NI9 epitope, was also seen in some B51 + individuals. Good control of viral load and higher CD4 + counts were significantly associated with at least one detectable T cell response to unmutated epitopes, whereas lower CD4 + counts and higher viral loads were observed in patients who had developed escape mutations in all three epitopes or who lacked T cell responses specific to these epitope(s). We propose that patients with HLA-B51 benefit from having multiple layers of effective defense against the development of immune escape mutations. Copyright © 2011 by The American Association of Immunologists, Inc.

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Dong T, Zhang Y, Xu KY, Yan H, James I, Peng Y, Blais M-E, Gaudieri S, Chen X, Lun W et al. 2011. Extensive HLA-driven viral diversity following a narrow-source HIV-1 outbreak in rural China BLOOD, 118 (1), pp. 98-106. | Show Abstract | Read more

Obstacles to developing an HIV-1 vaccine include extensive viral diversity and lack of correlates of protective immunity. High mutation rates allow HIV-1 to adapt rapidly to selective forces such as antiretroviral therapy and immune pressure, including HIV-1-specific CTLs that select viral variants which escape T-cell recognition. Multiple factors contribute to HIV-1 diversity, making it difficult to disen-tangle the contribution of CTL selection without using complex analytical approaches. We describe an HIV-1 outbreak in 231 former plasma donors in China, where a narrow-source virus that had contaminated the donation system was apparently transmitted to many persons contemporaneously. The genetic divergence now evident in these subjects should uniquely reveal how much viral diversity at the population level is solely attributable to host factors. We found significant correlations between pair-wise divergence of viral sequences and HLA class I genotypes across epitope-length windows in HIV-1 Gag, reverse transcriptase, integrase, and Nef, corresponding to sites of 140 HLA class I allele-associated viral polymorphisms. Of all polymorphic sites across these 4 proteins, 24%-56% were sites of HLA-associated selection. These data confirm that CTL pressure has a major effect on inter-host HIV-1 viral diversity and probably represents a key element of viral control. © 2011 by The American Society of Hematology.

Ranasinghe SRF, Kramer HB, Wright C, Kessler BM, di Gleria K, Zhang Y, Gillespie GM, Blais M-E, Culshaw A, Pichulik T et al. 2011. The Antiviral Efficacy of HIV-Specific CD8(+) T-Cells to a Conserved Epitope Is Heavily Dependent on the Infecting HIV-1 Isolate PLOS PATHOGENS, 7 (5), | Show Abstract | Read more

A major challenge to developing a successful HIV vaccine is the vast diversity of viral sequences, yet it is generally assumed that an epitope conserved between different strains will be recognised by responding T-cells. We examined whether an invariant HLA-B8 restricted Nef 90-97 epitope FL8 shared between five high titre viruses and eight recombinant vaccinia viruses expressing Nef from different viral isolates (clades A-H) could activate antiviral activity in FL8-specific cytotoxic T-lymphocytes (CTL). Surprisingly, despite epitope conservation, we found that CTL antiviral efficacy is dependent on the infecting viral isolate. Only 23% of Nef proteins, expressed by HIV-1 isolates or as recombinant vaccinia-Nef, were optimally recognised by CTL. Recognition of the HIV-1 isolates by CTL was independent of clade-grouping but correlated with virus-specific polymorphisms in the epitope flanking region, which altered immunoproteasomal cleavage resulting in enhanced or impaired epitope generation. The finding that the majority of virus isolates failed to present this conserved epitope highlights the importance of viral variance in CTL epitope flanking regions on the efficiency of antigen processing, which has been considerably underestimated previously. This has important implications for future vaccine design strategies since efficient presentation of conserved viral epitopes is necessary to promote enhanced anti-viral immune responses. © 2011 Ranasinghe et al.

Dong T, Zhang Y, Xu KY, Yan H, James I, Peng Y, Blais M-E, Gaudieri S, Chen X, Lun W et al. 2011. Extensive HLA-driven viral diversity following a narrow-source HIV-1 outbreak in rural China. Blood, 118 (1), pp. 98-106. | Show Abstract | Read more

Obstacles to developing an HIV-1 vaccine include extensive viral diversity and lack of correlates of protective immunity. High mutation rates allow HIV-1 to adapt rapidly to selective forces such as antiretroviral therapy and immune pressure, including HIV-1-specific CTLs that select viral variants which escape T-cell recognition. Multiple factors contribute to HIV-1 diversity, making it difficult to disentangle the contribution of CTL selection without using complex analytical approaches. We describe an HIV-1 outbreak in 231 former plasma donors in China, where a narrow-source virus that had contaminated the donation system was apparently transmitted to many persons contemporaneously. The genetic divergence now evident in these subjects should uniquely reveal how much viral diversity at the population level is solely attributable to host factors. We found significant correlations between pair-wise divergence of viral sequences and HLA class I genotypes across epitope-length windows in HIV-1 Gag, reverse transcriptase, integrase, and Nef, corresponding to sites of 140 HLA class I allele-associated viral polymorphisms. Of all polymorphic sites across these 4 proteins, 24%-56% were sites of HLA-associated selection. These data confirm that CTL pressure has a major effect on inter-host HIV-1 viral diversity and probably represents a key element of viral control.

Dang S-S, Wang W-J, Gao N, Wang S-D, Li M, Liu L-Y, Sun M-Z, Dong T. 2011. Apoptotic bone marrow CD34+ cells in cirrhotic patients. World J Gastroenterol, 17 (15), pp. 2044-2048. | Show Abstract | Read more

AIM: To access the frequency and level of apoptotic CD34+ cells isolated from the marrow fluid of patients with post-hepatitis cirrhosis. METHODS: The frequency of bone marrow CD34+ cells and apoptotic bone marrow CD34+ cells in 31 in-patients with post-hepatitis cirrhosis (cirrhosis group), and 15 out-patients without liver or blood disorders (control group) was calculated by flow cytometry. Parameters were collected to evaluate liver functions of patients in cirrhosis group. RESULTS: The percentage of normal bone marrow CD34+ cells was 6.30% ± 2.48% and 1.87% ± 0.53% (t = 3.906, P < 0.01) while that of apoptotic marrow CD34+ cells was 15.00% ± 15.81% and 5.73% ± 1.57% (t = 2.367, P < 0.05) in cirrhosis and control groups, respectively. The percentage of apoptotic marrow CD34+ cells was 6.25% ± 3.30% and 20.92 ± 18.5% (t = 2.409, P < 0.05) in Child-Pugh A and Child-Pugh B + C cirrhotic patients, respectively. The percentage of late apoptotic marrow CD34+ cells was positively correlated with the total bilirubin and aspartate aminotransferase serum levels in patients with cirrhosis. CONCLUSION: The status of CD34+ marrow cells in cirrhotic patients may suggest that the ability of hematopoietic progenitor cells to transform into mature blood cells is impaired.

Blais M-E, Dong T, Rowland-Jones S. 2011. HLA-C as a mediator of natural killer and T-cell activation: spectator or key player? Immunology, 133 (1), pp. 1-7. | Show Abstract | Read more

The biochemical properties of the HLA-C antigen differ substantially from those of HLA-A and -B molecules. For this reason, HLA-C diversity and expression at the cell surface are much lower than its counterparts and in consequence HLA-C-restricted responses have been infrequently detected and described. In this review we summarise the key differences between HLA-C and other class I molecules and provide an update on natural killer and T-cell responses restricted by HLA-C. We also discuss the different clinical settings associated with HLA-C alleles which mainly consist of autoimmune disorders, cancers and chronic infections.

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Blais ME, Dong T, Rowland-Jones S. 2011. HLA-C as a mediator of natural killer and T-cell activation: Spectator or key player? Immunology, 133 (1), pp. 1-7. | Show Abstract | Read more

The biochemical properties of the HLA-C antigen differ substantially from those of HLA-A and -B molecules. For this reason, HLA-C diversity and expression at the cell surface are much lower than its counterparts and in consequence HLA-C-restricted responses have been infrequently detected and described. In this review we summarise the key differences between HLA-C and other class I molecules and provide an update on natural killer and T-cell responses restricted by HLA-C. We also discuss the different clinical settings associated with HLA-C alleles which mainly consist of autoimmune disorders, cancers and chronic infections. © 2011 The Authors. Immunology © 2011 Blackwell Publishing Ltd.

De Santo C, Salio M, Dong T, Reiter Y, Cerundolo V. 2011. Cerundolo et al. respond Nature Immunology, 12 (11), pp. 1018-1020. | Read more

Zhang Y, Guo D, Zhao Y, Chen X, Ma L, Jin Y, Yan H, Wu H, Wei L, Dong T, Chen X. 2011. The effect of cytokine profiles on the viral response to re-treatment in antiviral-experienced patients with chronic hepatitis C virus infection ANTIVIRAL RESEARCH, 92 (2), pp. 247-254. | Show Abstract | Read more

Background: There have been few studies on the potential immunological factors associated with viral controls in antiviral-experienced patients on a second round of combination therapy. In this study, we evaluated the level of systemic cytokines and potential impact on combination therapy in both antiviral-naïve and -experienced patients chronically infected with hepatitis C virus. Methods: Longitudinal analysis of 27 cytokines and chemokines was performed using the multiplex Biorad 27 plex assay in 37 antiviral-naïve and 24 experienced chronically HCV-1b-infected patients during combination therapy with peginterferon-alfa and ribavirin. A group of healthy donors was included as the control (n=11). Results: Fifty percent of antiviral-experienced chronically HCV-patients could achieve a delayed and slow virologic response after 48. weeks combination therapy, comparing with an early and fast virologic response in antiviral-naïve patients. A distinction of immune mediators profiling before and during antiviral therapy between antiviral-naïve and -experienced patients was identified, IL-4, IFN-γ and CCL-3 (MIP-1a) were significantly higher in naïve patients than those in experienced patients (P=0.005, 0.047 and 0.017, respectively) while G-CSF in naïve was lower than in experienced patients (P < 0.05). Notably, higher Th1 type cytokine IFN-γ and lower Th2 type cytokine IL-4 at baseline and week 4 were associated with HCV clearance in naïve patients, and a similar trend appeared at week 12 in experienced patients. Conclusions: We found a successful second round therapy in antiviral-experienced patients appears to be associated with the host immune response. Dominant Th1-polar cytokines, especially IFN-γ, is a potential predictor of viral responsiveness. © 2011 Elsevier B.V.

De Santo C, Salio M, Dong T, Reiter Y, Cerundolo V. 2011. Reply to "Failure to detect production of IL-10 by activated human neutrophils". Nat Immunol, 12 (11), pp. 1018-1020. | Read more

Zhang Y, Guo D, Zhao Y, Chen X, Ma L, Jin Y, Yan H, Wu H, Wei L, Dong T, Chen X. 2011. The effect of cytokine profiles on the viral response to re-treatment in antiviral-experienced patients with chronic hepatitis C virus infection. Antiviral Res, 92 (2), pp. 247-254. | Show Abstract | Read more

BACKGROUND: There have been few studies on the potential immunological factors associated with viral controls in antiviral-experienced patients on a second round of combination therapy. In this study, we evaluated the level of systemic cytokines and potential impact on combination therapy in both antiviral-naïve and -experienced patients chronically infected with hepatitis C virus. METHODS: Longitudinal analysis of 27 cytokines and chemokines was performed using the multiplex Biorad 27 plex assay in 37 antiviral-naïve and 24 experienced chronically HCV-1b-infected patients during combination therapy with peginterferon-alfa and ribavirin. A group of healthy donors was included as the control (n=11). RESULTS: Fifty percent of antiviral-experienced chronically HCV-patients could achieve a delayed and slow virologic response after 48 weeks combination therapy, comparing with an early and fast virologic response in antiviral-naïve patients. A distinction of immune mediators profiling before and during antiviral therapy between antiviral-naïve and -experienced patients was identified, IL-4, IFN-γ and CCL-3 (MIP-1a) were significantly higher in naïve patients than those in experienced patients (P=0.005, 0.047 and 0.017, respectively) while G-CSF in naïve was lower than in experienced patients (P<0.05). Notably, higher Th1 type cytokine IFN-γ and lower Th2 type cytokine IL-4 at baseline and week 4 were associated with HCV clearance in naïve patients, and a similar trend appeared at week 12 in experienced patients. CONCLUSIONS: We found a successful second round therapy in antiviral-experienced patients appears to be associated with the host immune response. Dominant Th1-polar cytokines, especially IFN-γ, is a potential predictor of viral responsiveness.

Godlee A, Almond MH, Dong T. 2011. Pathogenesis of influenza: virus-host interactions. Expert Rev Anti Infect Ther, 9 (8), pp. 573-575. | Show Abstract | Read more

Since their inception in March 1972, Keystone Symposia on Molecular and Cellular Biology have brought together scientists from across the globe to discuss key biological topics. Now in its 40th year, it is a completely independent, nonprofit organization devoted solely to providing outstanding scientific conferences in all areas of the biological and biomedical sciences. Towards the end of May 2011, over 200 virologists and immunologists came to Hong Kong, an appropriate setting given the emergence of H5N1, to discuss influenza virus and host interactions. The meeting, expertly organized by Siamon Gordon (University of Oxford, Oxofrd, UK), Malik Peiris (University of Hong Kong, Hong Kong, China) and Kanta Subbarao (NIAID, NIH, MD, USA), took place in the aftermath of the first pandemic in 40 years and provided great insight into both pandemic H1N1 and H5N1. This article focuses on some of the recurring themes that were discussed during the week.

Slyker JA, John-Stewart GC, Dong T, Lohman-Payne B, Reilly M, Atzberger A, Taylor S, Maleche-Obimbo E, Mbori-Ngacha D, Rowland-Jones SL. 2011. Phenotypic characterization of HIV-specific CD8+ T cells during early and chronic infant HIV-1 infection. PLoS One, 6 (5), pp. e20375. | Show Abstract | Read more

Although CD8(+) T cells play an important role in the containment of adult HIV-1 replication, their role in infant HIV-1 infection is not as well understood. Impaired HIV-specific CD8(+) T cell responses may underlie the persistently high viral loads observed in infants. We examined the frequency and phenotype of infant HIV-specific CD8(+) T cells in 7 HIV-infected antiretroviral therapy-naïve infants during the first 2 years of life, using class I HLA tetramers and IFN-γ-ELISPOT. The frequency (0.088-3.9% of CD3(+)CD8(+) cells) and phenotype (CD27(+)CD28(-), CD45RA(+/-), CD57(+/-), HLA-DR(+), CD95(+)) of infant HIV-specific CD8(+) T cells were similar to reports in adults undergoing early infection. Unlike adults, at 23-24 months post-infection a high frequency of HIV-specific CD8(+) T cells expressed HLA-DR (mean 80%, range 68-85%) and CD95 (mean 88%, range 79-96%), suggesting sustained activation and vulnerability to apoptosis. Despite comparable expansion of HIV-specific CD8(+) T cells of a similar phenotype to adults during early infection, infant T cells failed to contain HIV-1 replication, and remained persistently activated and vulnerable to apoptosis during chronic infection.

Dushek O, Aleksic M, Wheeler RJ, Zhang H, Cordoba S-P, Peng Y-C, Chen J-L, Cerundolo V, Dong T, Coombs D, van der Merwe PA. 2011. Antigen potency and maximal efficacy reveal a mechanism of efficient T cell activation. Sci Signal, 4 (176), pp. ra39. | Show Abstract | Read more

T cell activation, a critical event in adaptive immune responses, depends on productive interactions between T cell receptors (TCRs) and antigens presented as peptide-bound major histocompatibility complexes (pMHCs). Activated T cells lyse infected cells, secrete cytokines, and perform other effector functions with various efficiencies, which depend on the binding parameters of the TCR-pMHC complex. The mechanism through which binding parameters are translated to the efficiency of T cell activation, however, remains controversial. The "affinity model" suggests that the dissociation constant (KD) of the TCR-pMHC complex determines the response, whereas the "productive hit rate model" suggests that the off-rate (koff) is critical. Here, we used mathematical modeling to show that antigen potency, as determined by the EC50 (half-maximal effective concentration), which is used to support KD-based models, could not discriminate between the affinity and the productive hit rate models. Both models predicted a correlation between EC50 and KD, but only the productive hit rate model predicted a correlation between maximal efficacy (Emax), the maximal T cell response induced by pMHC, and koff. We confirmed the predictions made by the productive hit rate model in experiments with cytotoxic T cell clones and a panel of pMHC variants. Thus, we propose that the activity of an antigen is determined by both its potency (EC50) and maximal efficacy (Emax).

Leligdowicz A, Onyango C, Yindom L-M, Peng Y, Cotten M, Jaye A, McMichael A, Whittle H, Dong T, Rowland-Jones S. 2010. Highly avid, oligoclonal, early-differentiated antigen-specific CD8+ T cells in chronic HIV-2 infection. Eur J Immunol, 40 (7), pp. 1963-1972. | Show Abstract | Read more

HIV-1-specific CD8(+) T cells are present in most HIV-1-infected people and play an important role in controlling viral replication, but the characteristics of an effective HIV-specific T-cell response are largely unknown. The majority of HIV-2-infected people behave as long-term non-progressors while those who progress to AIDS do so in a manner indistinguishable from HIV-1. A detailed study of HIV-2 infection may identify protective immune responses. Robust gag p26-specific T-cell responses are elicited during HIV-2 infection and correlate with control of viremia. In this study, we analyzed features of an HLA-B 3501-restricted T-cell response to HIV-2 p26 that may contribute to virus control. In contrast to HIV-1, HIV-2-specific T cells are at an early stage of differentiation (CD27(+)CD28(+)), a finding that relates directly to CD4(+) T-cell levels and inversely to immune activation. The cells demonstrate IFN-gamma secretion, oligoclonal T-cell receptor Vbeta gene segment usage, exceptional avidity and secretion of pro-inflammatory cytokines. Despite the potentially strong selection pressure imposed on the virus by these cells, there was no evidence of HIV-2 sequence evolution. We propose that in chronic HIV-2 infection, the maintenance of early-differentiated, highly avid CD8(+) T cells could account for the non-progressive course of disease. Such responses may be desirable from an HIV vaccine.

Dung NTP, Duyen HTL, Thuy NTV, Ngoc TV, Chau NVV, Hien TT, Rowland-Jones SL, Dong T, Farrar J, Wills B, Simmons CP. 2010. Timing of CD8+ T cell responses in relation to commencement of capillary leakage in children with dengue. J Immunol, 184 (12), pp. 7281-7287. | Show Abstract | Read more

Immune activation is a feature of dengue hemorrhagic fever (DHF) and CD8+ T cell responses in particular have been suggested as having a role in the vasculopathy that characterizes this disease. By phenotyping CD8+ T cells (CD38+/HLA-DR+, CD38+/Ki-67+, or HLA-DR+/Ki-67+) in serial blood samples from children with dengue, we found no evidence of increased CD8+ T cell activation prior to the commencement of resolution of viremia or hemoconcentration. Investigations with MHC class I tetramers to detect NS3(133-142)-specific CD8+ T cells in two independent cohorts of children suggested the commencement of hemoconcentration and thrombocytopenia in DHF patients generally begins before the appearance of measurable frequencies of NS3(133-142)-specific CD8+ T cells. The temporal mismatch between the appearance of measurable surface activated or NS3(133-142)-specific CD8+ T cells suggests that these cells are sequestered at sites of infection, have phenotypes not detected by our approach, or that other mechanisms independent of CD8+ T cells are responsible for early triggering of capillary leakage in children with DHF.

Makadzange AT, Gillespie G, Dong T, Kiama P, Bwayo J, Kimani J, Plummer F, Easterbrook P, Rowland-Jones SL. 2010. Characterization of an HLA-C-restricted CTL response in chronic HIV infection. Eur J Immunol, 40 (4), pp. 1036-1041. | Show Abstract | Read more

HIV-specific CTL play an important role in the host control of HIV infection. HIV-nef may facilitate escape of HIV-infected cells from CTL recognition by selectively downregulating the expression of HLA-A and HLA-B molecules, while surface expression of HLA-C is unaffected. The HLA-C-restricted CTL responses have previously been largely ignored and poorly characterized. We examined the frequency, function, and phenotype of HLA-C-restricted CTL in ten antiretroviral therapy-naïve Caucasian and African individuals with chronic HIV-1 infection (for at least 8 years; CD4 cell counts in the range of 50-350) who carried the HLA-Cw04 allele. HLA-Cw04-restricted CTL that recognize a conserved epitope within HIV-1 envelope (aa 375-383 SF9) were analyzed using IFN-gamma ELISPOT assays and phenotypic analysis was carried out by flow cytometry. HLA-C-restricted CTL play an important role in the HIV-specific response, and can account for as much as 54% of the total response. HLA-C-restricted CTL are functionally and phenotypically identical to HLA-A- and HLA-B-restricted CTL. HLA-C-restricted CTL in chronic HIV infection are memory cells of an intermediate phenotype, characterized by high CD27 and low CD28 expression and lack of perforin production.

Leligdowicz A, Onyango C, Yindom LM, Peng YC, Cotten M, Jaye A, McMichael A, Whittle H, Dong T, Rowland-Jones S. 2010. Highly avid, oligoclonal, early-differentiated antigen-specific CD8<sup>+</sup>T cells in chronic HIV-2 infection European Journal of Immunology, 40 (7), pp. 1963-1972. | Show Abstract | Read more

HIV-1-specific CD8 + T cells are present in most HIV-1-infected people and play an important role in controlling viral replication, but the characteristics of an effective HIV-specific T-cell response are largely unknown. The majority of HIV-2-infected people behave as long-term non-progressors while those who progress to AIDS do so in a manner indistinguishable from HIV-1. A detailed study of HIV-2 infection may identify protective immune responses. Robust gag p26-specific T-cell responses are elicited during HIV-2 infection and correlate with control of viremia. In this study, we analyzed features of an HLA-B*3501-restricted T-cell response to HIV-2 p26 that may contribute to virus control. In contrast to HIV-1, HIV-2-specific T cells are at an early stage of differentiation (CD27 + CD28 + ), a finding that relates directly to CD4 + T-cell levels and inversely to immune activation. The cells demonstrate IFN-γ secretion, oligoclonal T-cell receptor Vβ gene segment usage, exceptional avidity and secretion of pro-inflammatory cytokines. Despite the potentially strong selection pressure imposed on the virus by these cells, there was no evidence of HIV-2 sequence evolution. We propose that in chronic HIV-2 infection, the maintenance of early-differentiated, highly avid CD8 + T cells could account for the nonprogressive course of disease. Such responses may be desirable from an HIV vaccine. © 2010 Wiley-VCH Verlag GmbH & Co. KGaA.

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Leligdowicz A, Feldmann J, Jaye A, Cotten M, Dong T, McMichael A, Whittle H, Rowland-Jones S. 2010. Direct relationship between virus load and systemic immune activation in HIV-2 infection Journal of Infectious Diseases, 201 (1), pp. 114-122. | Show Abstract | Read more

Immune activation is a hallmark of disease progression in human immunodeficiency virus (HIV) type 1 (HIV1) and HIV type 2 (HIV-2) infection. However, the relationship between viremia and systemic immune activation is unclear. We assessed the relationship between HIV-2 plasma virus load and immune system activation in a cross-sectional study in a community cohort of HIV-1-positive, HIV-2-positive, and HIV-negative patients, in which many HIV-2-positive patients had nonprogressing infection. HLA-DR and CD38 expression on CD4 + and CD8 + T cells was measured, as were plasma β 2 -microglobulin levels. These markers were related to clinical (virus load and CD4 + cell count) and immunological (HIV-2-specific interferon γ secretion) correlates of delayed disease progression. A consistent positive correlation was identified between the level of HIV-2 viremia and immune activation. We propose that increasing virus load may contribute to systemic immune activation in HIV-2 infection. © 2009 by the Infectious Diseases Society of America. All rights reserved.

Leligdowicz A, Feldmann J, Jaye A, Cotten M, Dong T, McMichael A, Whittle H, Rowland-Jones S. 2010. Direct relationship between virus load and systemic immune activation in HIV-2 infection. J Infect Dis, 201 (1), pp. 114-122. | Show Abstract | Read more

Immune activation is a hallmark of disease progression in human immunodeficiency virus (HIV) type 1 (HIV-1) and HIV type 2 (HIV-2) infection. However, the relationship between viremia and systemic immune activation is unclear. We assessed the relationship between HIV-2 plasma virus load and immune system activation in a cross-sectional study in a community cohort of HIV-1-positive, HIV-2-positive, and HIV-negative patients, in which many HIV-2-positive patients had nonprogressing infection. HLA-DR and CD38 expression on CD4(+) and CD8(+) T cells was measured, as were plasma beta(2)-microglobulin levels. These markers were related to clinical (virus load and CD4(+) cell count) and immunological (HIV-2-specific interferon gamma secretion) correlates of delayed disease progression. A consistent positive correlation was identified between the level of HIV-2 viremia and immune activation. We propose that increasing virus load may contribute to systemic immune activation in HIV-2 infection.

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Denney L, Aitken C, Li CKF, Wilson-Davies E, Kok WL, Clelland C, Rooney K, Young D, Dong T, McMichael AJ et al. 2010. Reduction of natural killer but not effector CD8 t lymphoyctes in three consecutive cases of severe/lethal H1N1/09 influenza a virus infection PLoS ONE, 5 (5), | Show Abstract | Read more

Background: The cause of severe disease in some patients infected with pandemic influenza A virus is unclear. Methodology/Principal Findings: We present the cellular immunology profile in the blood, and detailed clinical (and postmortem) findings of three patients with rapidly progressive infection, including a pregnant patient who died. The striking finding is of reduction in natural killer (NK) cells but preservation of activated effector CD8 T lymphocytes; with viraemia in the patient who had no NK cells. Comparison with control groups suggests that the reduction of NK cells is unique to these severely ill patients. Conclusion/Significance: Our report shows markedly reduced NK cells in the three patients that we sampled and raises the hypothesis that NK may have a more significant role than T lymphocytes in controlling viral burden when the host is confronted with a new influenza A virus subtype. © 2010 Denney et al.

Denney L, Aitken C, Li CK-F, Wilson-Davies E, Kok WL, Clelland C, Rooney K, Young D, Dong T, McMichael AJ et al. 2010. Reduction of natural killer but not effector CD8 T lymphocytes in three consecutive cases of severe/lethal H1N1/09 influenza A virus infection. PLoS One, 5 (5), pp. e10675. | Show Abstract | Read more

BACKGROUND: The cause of severe disease in some patients infected with pandemic influenza A virus is unclear. METHODOLOGY/PRINCIPAL FINDINGS: We present the cellular immunology profile in the blood, and detailed clinical (and post-mortem) findings of three patients with rapidly progressive infection, including a pregnant patient who died. The striking finding is of reduction in natural killer (NK) cells but preservation of activated effector CD8 T lymphocytes; with viraemia in the patient who had no NK cells. Comparison with control groups suggests that the reduction of NK cells is unique to these severely ill patients. CONCLUSION/SIGNIFICANCE: Our report shows markedly reduced NK cells in the three patients that we sampled and raises the hypothesis that NK may have a more significant role than T lymphocytes in controlling viral burden when the host is confronted with a new influenza A virus subtype.

Feldmann J, Leligdowicz A, Jaye A, Dong T, Whittle H, Rowland-Jones SL. 2009. Downregulation of the T-cell receptor by human immunodeficiency virus type 2 Nef does not protect against disease progression. J Virol, 83 (24), pp. 12968-12972. | Show Abstract | Read more

Chronic immune activation is thought to play a major role in human immunodeficiency virus (HIV) pathogenesis, but the relative contributions of multiple factors to immune activation are not known. One proposed mechanism to protect against immune activation is the ability of Nef proteins from some HIV and simian immunodeficiency virus strains to downregulate the T-cell receptor (TCR)-CD3 complex of the infected cell, thereby reducing the potential for deleterious activation. HIV type 1 (HIV-1) Nef has lost this property. In contrast to HIV-1, HIV-2 infection is characterized by a marked disparity in the disease course, with most individuals maintaining a normal life span. In this study, we examined the relationship between the ability of HIV-2 Nef proteins to downregulate the TCR and immune activation, comparing progressors and nonprogressors. Representative Nef variants were isolated from 28 HIV-2-infected individuals. We assessed their abilities to downregulate the TCR from the surfaces of CD4 T cells. In the same individuals, the activation of peripheral lymphocytes was evaluated by measurement of the expression levels of HLA-DR and CD38. We observed a striking correlation of the TCR downregulation efficiency of HIV-2 Nef variants with immune activation in individuals with a low viral load. This strongly suggests that Nef expression can influence the activation state of the immune systems of infected individuals. However, the efficiency of TCR downregulation by Nef was not reduced in progressing individuals, showing that TCR downregulation does not protect against progression in HIV-2 infection.

Yang H, Guimarães-Walker A, Hibbs S, Dong T, Stacey A, Borrow P, Hanke T, Davenport MP, McMichael A, Dorrell L. 2009. Interleukin-10 responses to therapeutic vaccination during highly active antiretroviral therapy and after analytical therapy interruption. AIDS, 23 (16), pp. 2226-2230. | Show Abstract | Read more

We investigated whether therapeutic vaccination in highly active antiretroviral therapy (HAART)-treated patients with a modified vaccinia virus Ankara-vectored HIV-1 vaccine, with or without therapy interruption, induced the production of interleukin (IL)-10. Plasma IL-10 levels were not significantly increased postvaccination, but increased in parallel with viraemia in patients who interrupted therapy. Surprisingly, IL-10 blockade augmented HIV-specific T cell proliferative responses in HAART-suppressed patients but had no effect once virological control was lost. Modulation of IL-10 might enhance vaccine-induced immune responses.

Slyker JA, Lohman-Payne BL, John-Stewart GC, Maleche-Obimbo E, Emery S, Richardson B, Dong T, Iversen AK, Mbori-Ngacha D, Overbaugh J et al. 2009. Acute cytomegalovirus infection in Kenyan HIV-infected infants. AIDS, 23 (16), pp. 2173-2181. | Show Abstract | Read more

OBJECTIVE: Cytomegalovirus (CMV) coinfection may influence HIV-1 disease progression during infancy. Our aim was to describe the incidence of CMV infection and the kinetics of viral replication in Kenyan HIV-infected and HIV-exposed uninfected infants. METHODS: HIV-1 and CMV plasma viral loads were serially measured in 20 HIV-exposed uninfected and 44 HIV-infected infants born to HIV-infected mothers. HIV-infected children were studied for the first 2 years of life, and HIV-exposed uninfected infants were studied for 1 year. RESULTS: CMV DNA was detected frequently during the first months of life; by 3 months of age, CMV DNA was detected in 90% of HIV-exposed uninfected infants and 93% of infants who had acquired HIV-1 in utero. CMV viral loads were highest in the 1-3 months following the first detection of virus and declined rapidly thereafter. CMV peak viral loads were significantly higher in the HIV-infected infants compared with the HIV-exposed uninfected infants (mean 3.2 versus 2.7 log10 CMV DNA copies/ml, respectively, P = 0.03). The detection of CMV DNA persisted to 7-9 months post-CMV infection in both the HIV-exposed uninfected (8/17, 47%) and HIV-infected (13/18, 72%, P = 0.2) children. Among HIV-infected children, CMV DNA was detected in three of the seven (43%) surviving infants tested between 19 and 21 months post-CMV infection. Finally, a strong correlation was found between peak CMV and HIV-1 viral loads (rho = 0.40, P = 0.008). CONCLUSION: Acute CMV coinfection is common in HIV-infected Kenyan infants. HIV-1 infection was associated with impaired containment of CMV replication.

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Sharma D, Bastard K, Guethlein LA, Norman PJ, Yawata N, Yawata M, Pando M, Thananchai H, Dong T, Rowland-Jones S et al. 2009. Dimorphic Motifs in D0 and D1+D2 Domains of Killer Cell Ig-Like Receptor 3DL1 Combine to Form Receptors with High, Moderate, and No Avidity for the Complex of a Peptide Derived from HIV and HLA-A*2402 JOURNAL OF IMMUNOLOGY, 183 (7), pp. 4569-4582. | Read more

Ishizuka J, Grebe K, Shenderov E, Peters B, Chen Q, Peng Y, Wang L, Dong T, Pasquetto V, Oseroff C et al. 2009. Quantitating T cell cross-reactivity for unrelated peptide antigens. J Immunol, 183 (7), pp. 4337-4345. | Show Abstract | Read more

Quantitating the frequency of T cell cross-reactivity to unrelated peptides is essential to understanding T cell responses in infectious and autoimmune diseases. Here we used 15 mouse or human CD8+ T cell clones (11 antiviral, 4 anti-self) in conjunction with a large library of defined synthetic peptides to examine nearly 30,000 TCR-peptide MHC class I interactions for cross-reactions. We identified a single cross-reaction consisting of an anti-self TCR recognizing a poxvirus peptide at relatively low sensitivity. We failed to identify any cross-reactions between the synthetic peptides in the panel and polyclonal CD8+ T cells raised to viral or alloantigens. These findings provide the best estimate to date of the frequency of T cell cross-reactivity to unrelated peptides ( approximately 1/30,000), explaining why cross-reactions between unrelated pathogens are infrequently encountered and providing a critical parameter for understanding the scope of self-tolerance.

Choudhuri K, Parker M, Milicic A, Cole DK, Shaw MK, Sewell AK, Stewart-Jones G, Dong T, Gould KG, van der Merwe PA. 2009. Peptide-major histocompatibility complex dimensions control proximal kinase-phosphatase balance during T cell activation. J Biol Chem, 284 (38), pp. 26096-26105. | Show Abstract | Read more

T cell antigen recognition requires binding of the T cell receptor (TCR) to a complex between peptide antigen and major histocompatibility complex molecules (pMHC), and this recognition occurs at the interface between the T cell and the antigen-presenting cell. The TCR and pMHC molecules are small compared with other abundant cell surface molecules, and it has been suggested that small size is functionally important. We show here that elongation of both mouse and human MHC class I molecules abrogates T cell antigen recognition as measured by cytokine production and target cell killing. This elongation disrupted tyrosine phosphorylation and Zap70 recruitment at the contact region without affecting TCR or coreceptor binding. Contact areas with elongated forms of pMHC showed an increase in intermembrane distance and less efficient segregation of CD3 from the large tyrosine phosphatase CD45. These findings demonstrate that T cell antigen recognition is strongly dependent on pMHC size and are consistent with models of TCR triggering requiring segregation or mechanical pulling of the TCR.

Li H, Chen X, Jin X, Liu Z, Huang X, Cao Z, Guo C, Dong T, Wu H. 2009. Proliferation, but not interleukin 2 production, of Gag-specific CD8+ T cells is associated with low HIV viremia and high CD4 counts in HIV-1-infected Chinese individuals. J Acquir Immune Defic Syndr, 52 (1), pp. 1-8. | Show Abstract | Read more

BACKGROUND: To control HIV globally, a comprehensive understanding of host immunity to HIV in different human populations is needed. Relatively, little is known on the quantity and quality of HIV-specific T-cell responses in Chinese patients. METHODS: We quantified HIV Gag-specific CD8+ and CD4+ T cells that are capable of producing interferon (IFN)-gamma and interleukin 2 and assessed their proliferative capacity in a cohort of 53 antiretroviral-naive chronically HIV-1-infected Chinese patients. RESULTS: The proliferation of Gag-specific CD8+ T cells, but not their IFN-gamma or interleukin 2 production, was inversely proportional to HIV viral load and directly proportional to CD4+ T-cell counts. Gag-specific CD8+ T-cell proliferation was proportionate to the frequency of IFN-gamma-secreting CD8+ T cells. Such correlations, however, did not exist for Gag-specific CD4 T cells. CONCLUSIONS: These results suggest that good quality and large quantities of HIV Gag-specific T-cell responses are associated with virologic control in HIV-1-infected Chinese patients. We infer that protective T-cell vaccines tested in other populations should also provide benefit to the Chinese population.

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John-Stewart GC, Mbori-Ngacha D, Payne BL, Farquhar C, Richardson BA, Emery S, Otieno P, Obimbo E, Dong T, Slyker J et al. 2009. HIV-1-Specific Cytotoxic T Lymphocytes and Breast Milk HIV-1 Transmission JOURNAL OF INFECTIOUS DISEASES, 199 (6), pp. 889-898. | Show Abstract | Read more

Background. Breast-feeding by infants exposed to human immunodeficiency virus type 1 (HIV-1) provides an opportunity to assess the role played by repeated HIV-1 exposure in eliciting HIV-1-specific immunity and in defining whether immune responses correlate with protection from infection. Methods. Breast-feeding infants born to HIV-1-seropositive women were assessed for HLA-selected HIV-1 peptide-specific cytotoxic T lymphocyte interferon (IFN)-γ responses by means of enzyme-linked immunospot (ELISpot) assays at 1, 3, 6, 9, and 12 months of age. Responses were deemed to be positive when they reached ≥50 HIV-1-specific sfu/1 × 10 6 peripheral blood mononuclear cells (PBMCs) and were at least twice those of negative controls. Results. A total of 807 ELISpot assays were performed for 217 infants who remained uninfected with HIV-1 at ̃12 months of age; 101 infants (47%) had at least 1 positive ELISpot result (median, 78-170 sfu/1 × 106 PBMCs). The prevalence and magnitude of responses increased with age (P = .01 and P = .007, respectively); the median log10 value for HIV-1-specific IFN-γ responses increased by 1.0 sfu/1 × 10 6 PBMCs/month (P < .001) between 1 and 12 months of age. Of 141 HIV-1-uninfected infants with 1-month ELISpot results, 10 (7%) acquired HIV-1 infection (0/16 with positive vs. 10/125 [8%] with negative ELISpot results; P = .6). Higher values for log 10 HIV-1-specific spot-forming units at 1 month of age were associated with a decreased risk of HIV-1 infection, adjusted for maternal HIV-1 RNA level (adjusted hazard ratio, 0.09 [95% confidence interval, 0.01- 0.72]). Conclusions. Breast-feeding HIV-1-exposed uninfected infants frequently had HIV-1-specific IFN-γ responses. Greater early HIV-1-specific IFN-γ responses were associated with decreased HIV-1 acquisition. © 2009 by the Infectious Diseases Society of America.

Brackenridge S, Corrah T, Haygreen E, Lavender K, Dong T, Goonetilleke N, Borrow P, McMichael A. 2009. Does increased expression of HLA-C allow better control of HIV-1 viral load? RETROVIROLOGY, 6 (Suppl 3), pp. P113-P113. | Read more

Ranasinghe SRF, Kramer HB, Wright C, Kessler BM, di Gleria K, Zhang Y, Gillespie GM, Blais M-E, Culshaw A, Pichulik T et al. 2011. The antiviral efficacy of HIV-specific CD8⁺ T-cells to a conserved epitope is heavily dependent on the infecting HIV-1 isolate. PLoS Pathog, 7 (5), pp. e1001341. | Show Abstract | Read more

A major challenge to developing a successful HIV vaccine is the vast diversity of viral sequences, yet it is generally assumed that an epitope conserved between different strains will be recognised by responding T-cells. We examined whether an invariant HLA-B8 restricted Nef₉₀₋₉₇ epitope FL8 shared between five high titre viruses and eight recombinant vaccinia viruses expressing Nef from different viral isolates (clades A-H) could activate antiviral activity in FL8-specific cytotoxic T-lymphocytes (CTL). Surprisingly, despite epitope conservation, we found that CTL antiviral efficacy is dependent on the infecting viral isolate. Only 23% of Nef proteins, expressed by HIV-1 isolates or as recombinant vaccinia-Nef, were optimally recognised by CTL. Recognition of the HIV-1 isolates by CTL was independent of clade-grouping but correlated with virus-specific polymorphisms in the epitope flanking region, which altered immunoproteasomal cleavage resulting in enhanced or impaired epitope generation. The finding that the majority of virus isolates failed to present this conserved epitope highlights the importance of viral variance in CTL epitope flanking regions on the efficiency of antigen processing, which has been considerably underestimated previously. This has important implications for future vaccine design strategies since efficient presentation of conserved viral epitopes is necessary to promote enhanced anti-viral immune responses.

Zhang YH, Zhao Y, Xu KY, Yan HP, Ma LN, Lun WH, Wu H, Dong T, Chen XY. 2009. Influence of HIV-1 specific T cell response on the progression of HIV-1 infection Chinese Journal of Microbiology and Immunology, 29 (10), pp. 934-938. | Show Abstract | Read more

Objective: To discuss the influence of HIV-1 specific T cell on disease progression of HIV-1 infection. Methods: Thirty-seven patients with HIV-1 infection were recruited from a cohort study and their HIV-1 specific T cell responses were analyzed using overlapping peptides and ELISP0T assay. Results: 83.78% (31/37) of candidates with HIV-1 infection responded to at least one peptide (magnitude was above 50 SFU/10 6 PBMCs). Peptides from HIV-1 subtype B proteins could elicit specific T cell responses in HIV-1 infections, and amongst them, the responses to HIV-1 Gag were the highest, not only in the frequencies of recognition, but also in the magnitude of response (F=17.969, P < 0.001). In addition, HIV-1 patients with different progression of disease expressed different T cell responses. The magnitude of response elicited by HIV-1 Gag protein in the patients with clinical asymptomatic stage was much higher than that in the patients with AIDS stage, although the responses to whole genome peptides between these two groups were similar. Conclusion: The specific T cell responses elicited by different HIV-1 proteins are different, and the responses to HIV-1 Gag protein may play the most important role in the progression of HIV-1 infection.

De Santo C, Salio M, Masri SH, Lee LY-H, Dong T, Speak AO, Porubsky S, Booth S, Veerapen N, Besra GS et al. 2008. Invariant NKT cells reduce the immunosuppressive activity of influenza A virus-induced myeloid-derived suppressor cells in mice and humans. J Clin Invest, 118 (12), pp. 4036-4048. | Show Abstract | Read more

Infection with influenza A virus (IAV) presents a substantial threat to public health worldwide, with young, elderly, and immunodeficient individuals being particularly susceptible. Inflammatory responses play an important role in the fatal outcome of IAV infection, but the mechanism remains unclear. We demonstrate here that the absence of invariant NKT (iNKT) cells in mice during IAV infection resulted in the expansion of myeloid-derived suppressor cells (MDSCs), which suppressed IAV-specific immune responses through the expression of both arginase and NOS, resulting in high IAV titer and increased mortality. Adoptive transfer of iNKT cells abolished the suppressive activity of MDSCs, restored IAV-specific immune responses, reduced IAV titer, and increased survival rate. The crosstalk between iNKT and MDSCs was CD1d- and CD40-dependent. Furthermore, IAV infection and exposure to TLR agonists relieved the suppressive activity of MDSCs. Finally, we extended these results to humans by demonstrating the presence of myeloid cells with suppressive activity in the PBLs of individuals infected with IAV and showed that their suppressive activity is substantially reduced by iNKT cell activation. These findings identify what we believe to be a novel immunomodulatory role of iNKT cells, which we suggest could be harnessed to abolish the immunosuppressive activity of MDSCs during IAV infection.

De Santo C, Salio M, Masri SH, Lee LY, Dong T, Speak AO, Porubsky S, Booth S, Veerapen N, Besra GS et al. 2008. Invariant NKT cells reduce the immunosuppressive activity of influenza A virus-induced myeloid-derived suppressor cells in mice and humans. J Clin Invest, 118 (12), pp. 4036-4048. | Show Abstract | Read more

Infection with influenza A virus (IAV) presents a substantial threat to public health worldwide, with young, elderly, and immunodeficient individuals being particularly susceptible. Inflammatory responses play an important role in the fatal outcome of IAV infection, but the mechanism remains unclear. We demonstrate here that the absence of invariant NKT (iNKT) cells in mice during IAV infection resulted in the expansion of myeloid-derived suppressor cells (MDSCs), which suppressed IAV-specific immune responses through the expression of both arginase and NOS, resulting in high IAV titer and increased mortality. Adoptive transfer of iNKT cells abolished the suppressive activity of MDSCs, restored IAV-specific immune responses, reduced IAV titer, and increased survival rate. The crosstalk between iNKT and MDSCs was CD1d- and CD40-dependent. Furthermore, IAV infection and exposure to TLR agonists relieved the suppressive activity of MDSCs. Finally, we extended these results to humans by demonstrating the presence of myeloid cells with suppressive activity in the PBLs of individuals infected with IAV and showed that their suppressive activity is substantially reduced by iNKT cell activation. These findings identify what we believe to be a novel immunomodulatory role of iNKT cells, which we suggest could be harnessed to abolish the immunosuppressive activity of MDSCs during IAV infection.

Lee LY-H, Ha DLA, Simmons C, de Jong MD, Chau NVV, Schumacher R, Peng YC, McMichael AJ, Farrar JJ, Smith GL et al. 2008. Memory T cells established by seasonal human influenza A infection cross-react with avian influenza A (H5N1) in healthy individuals. J Clin Invest, 118 (10), pp. 3478-3490. | Show Abstract | Read more

The threat of avian influenza A (H5N1) infection in humans remains a global health concern. Current influenza vaccines stimulate antibody responses against the surface glycoproteins but are ineffective against strains that have undergone significant antigenic variation. An alternative approach is to stimulate pre-existing memory T cells established by seasonal human influenza A infection that could cross-react with H5N1 by targeting highly conserved internal proteins. To determine how common cross-reactive T cells are, we performed a comprehensive ex vivo analysis of cross-reactive CD4+ and CD8+ memory T cell responses to overlapping peptides spanning the full proteome of influenza A/Viet Nam/CL26/2005 (H5N1) and influenza A/New York/232/2004 (H3N2) in healthy individuals from the United Kingdom and Viet Nam. Memory CD4+ and CD8+ T cells isolated from the majority of participants exhibited human influenza-specific responses and showed cross-recognition of at least one H5N1 internal protein. Participant CD4+ and CD8+ T cells recognized multiple synthesized influenza peptides, including peptides from the H5N1 strain. Matrix protein 1 (M1) and nucleoprotein (NP) were the immunodominant targets of cross-recognition. In addition, cross-reactive CD4+ and CD8+ T cells recognized target cells infected with recombinant vaccinia viruses expressing either H5N1 M1 or NP. Thus, vaccine formulas inducing heterosubtypic T cell-mediated immunity may confer broad protection against avian and human influenza A viruses.

Gaiha GD, Dong T, Palaniyar N, Mitchell DA, Reid KBM, Clark HW. 2008. Surfactant protein A binds to HIV and inhibits direct infection of CD4+ cells, but enhances dendritic cell-mediated viral transfer. J Immunol, 181 (1), pp. 601-609. | Show Abstract

The identification of surfactant protein A (SP-A) as an important innate immune factor of the lungs, amniotic fluid, and the vaginal tract suggests that it could play an important role during various stages of HIV disease progression and transmission. Therefore, we examined whether SP-A could bind to HIV and also had any effect on viral infectivity. Our data demonstrate that SP-A binds to HIV in a calcium-dependent manner that is inhibitable by mannose and EDTA. Affinity capture of the HIV viral lysate reveals that SP-A targets the envelope glycoprotein of HIV (gp120), which was confirmed by ELISA using recombinant gp120. Digestion of gp120 with endoglycosidase H abrogates the binding of SP-A, indicating that the high mannose structures on gp120 are the target of the collectin. Infectivity studies reveal that SP-A inhibits the infection of CD4+ T cells by two strains of HIV (BaL, IIIB) by >80%. Competition assays with CD4 and mAbs F105 and b12 suggest that SP-A inhibits infectivity by occlusion of the CD4-binding site. Studies with dendritic cells (DCs) demonstrate that SP-A enhances the binding of gp120 to DCs, the uptake of viral particles, and the transfer of virus from DCs to CD4+ T cells by >5-fold at a pH representative of the vaginal tract. Collectively, these results suggest that SP-A acts as a dual modulator of HIV infection by protecting CD4+ T cells from direct infection but enhancing the transfer of infection to CD4+ T cells mediated by DCs.

Kemal KS, Beattie T, Dong T, Weiser B, Kaul R, Kuiken C, Sutton J, Lang D, Yang H, Peng YC et al. 2008. Transition from long-term nonprogression to HIV-1 disease associated with escape from cellular immune control. J Acquir Immune Defic Syndr, 48 (2), pp. 119-126. | Show Abstract | Read more

Transition from long-term nonprogressive infection to progressive HIV-1 disease presents an opportunity to investigate pathogenesis in a defined immunogenetic background. We studied a male long-term nonprogressor (LTNP) who remained asymptomatic and viremic and had normal CD4 T-cell counts without antiretroviral therapy for >18 years and then experienced a transition to disease progression. We analyzed the complete HIV-1 genomic RNA sequence from plasma and cellular immune responses to predefined human leukocyte antigen-matched autologous viral peptides spanning the viral genome, before and after progression. Serial viral sequences did not seem attenuated and consistently utilized coreceptor CCR5. LTNP status was associated with elongated V2 domains and broad low-level T-cell immune responses targeting several regions of the viral genome. The transition to progressive disease was associated with the acquisition of viral mutations conferring escape from CD8 T-cell responses. Multiple changes in HIV-1 sequence and loss of immune response over time most likely contributed to the transition from LTNP status to progressive disease. These data are relevant to vaccine design and identification of the correlates of protection from disease progression.

Abidi SHI, Dong T, Vuong MT, Sreenu VB, Rowland-Jones SL, Evans EJ, Davis SJ. 2008. Differential remodeling of a T-cell transcriptome following CD8- versus CD3-induced signaling. Cell Res, 18 (6), pp. 641-648. | Show Abstract | Read more

CD8 engagement with class I major histocompatibility antigens greatly enhances T-cell activation, but it is not clear how this is achieved. We address the question of whether or not the antibody-mediated ligation of CD8 alone induces transcriptional remodeling in a T-cell clone, using serial analysis of gene expression. Even though it fails to induce overt phenotypic changes, we find that CD8 ligation profoundly alters transcription in the T-cell clone, at a scale comparable to that induced by antibody-mediated ligation of CD3. The character of the resulting changes is distinct, however, with the net effect of CD8 ligation being substantially inhibitory. We speculate that ligating CD8 induces weak, T-cell receptor (TCR)-mediated inhibitory signals reminiscent of the effects of TCR antagonists. Our results imply that CD8 ligation alone is incapable of activating the T-cell clone because it fails to fully induce NFAT-dependent transcription.

Moran E, Simmons C, Chau NV, Luhn K, Wills B, Phuong Dung N, Thao LTT, Hien TT, Farrar J, Rowland-Jones S, Dong T. 2008. Preservation of a critical epitope core region is associated with the high degree of flaviviral cross-reactivity exhibited by a dengue-specific CD4+ T cell clone. Eur J Immunol, 38 (4), pp. 1050-1057. | Show Abstract | Read more

Dengue is a member of the Flaviviridae, a large group of related viruses some of which co-circulate in certain regions (e.g. dengue and Yellow fever in South America). Immune responses cross-reactive between different dengue serotypes are important in the pathogenesis of dengue disease but it is not known whether previous infection with one flavivirus might affect the clinical course of subsequent infections with other members of the family. CD4+ T cells have been shown to be important in the production of cytokines in response to dengue infection and can demonstrate significant epitope cross-reactivity. Here, we describe the generation and characterisation of CD4+ T cell clones from a patient experiencing acute dengue infection. These clones were DRB1*15+ and recognised epitope variants not only within other dengue viruses but certain other flaviviruses. This cross-reactivity was dependent upon the presence of a five-amino acid core region, consistent with structural observations of class II MHC binding to TCR demonstrating that only a subset of residues within an epitope bound to a class II molecule are "read out" by the TCR. This capacity of CD4+ T cell clones to recognise a given epitope despite considerable variation between viruses may be of pathological significance, particularly in regions where related viruses co-circulate.

Rowland-Jones S, Dong T. 2007. Dying T cells trigger autoimmunity in HIV. Nat Med, 13 (12), pp. 1413-1415. | Show Abstract | Read more

During HIV-1 infection, there are many ways for CD4 + T cells to die. New findings suggest that an autoimmune mechanism may come into play (pages 1431-1439). © 2007 Nature Publishing Group.

Rowland-Jones S, Dong T. 2007. Dying T cells trigger autoimmunity in HIV NATURE MEDICINE, 13 (12), pp. 1413-1415. | Read more

Leligdowicz A, Yindom L-M, Onyango C, Sarge-Njie R, Alabi A, Cotten M, Vincent T, da Costa C, Aaby P, Jaye A et al. 2007. Robust Gag-specific T cell responses characterize viremia control in HIV-2 infection. J Clin Invest, 117 (10), pp. 3067-3074. | Show Abstract | Read more

HIV-2 infection in the majority of infected subjects follows an attenuated disease course that distinguishes it from infection with HIV-1. Antigen-specific T cells are pivotal in the management of chronic viral infections but are not sufficient to control viral replication in HIV-1-positive subjects, and their function in HIV-2 infection is not fully established. In a community-based cohort of HIV-2 long-term nonprogressors in rural Guinea-Bissau, we performed what we believe is the first comprehensive analysis of HIV-2-specific immune responses. We demonstrate that Gag is the most immunogenic protein. The magnitude of the IFN-gamma immune response to the HIV-2 proteome was inversely correlated with HIV-2 viremia, and this relationship was specifically due to the targeting of Gag. Furthermore, patients with undetectable viremia had greater Gag-specific responses compared with patients with high viral replication. The most frequently recognized peptides clustered within a defined region of Gag, and responses to a single peptide in this region were associated with low viral burden. The consistent relationship between Gag-specific immune responses and viremia control suggests that T cell responses are vital in determining the superior outcome of HIV-2 infection. A better understanding of how HIV-2 infection is controlled may identify correlates of effective protective immunity essential for the design of HIV vaccines.

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Leligdowicz A, Yindom L-M, Onyango C, Sarge-Njie R, Alabi A, Cotten M, Vincent T, da Costa C, Aaby P, Jaye A et al. 2007. Robust gag-specific T cell responses characterize viremia control in HIV-2 infection JOURNAL OF CLINICAL INVESTIGATION, 117 (10), pp. 3067-3074. | Read more

Yang H, Dong T, Turnbull E, Ranasinghe S, Ondondo B, Goonetilleke N, Winstone N, di Gleria K, Bowness P, Conlon C et al. 2007. Broad TCR usage in functional HIV-1-specific CD8+ T cell expansions driven by vaccination during highly active antiretroviral therapy. J Immunol, 179 (1), pp. 597-606. | Show Abstract

During chronic HIV-1 infection, continuing viral replication is associated with impaired proliferative capacity of virus-specific CD8+ T cells and with the expansion and persistence of oligoclonal T cell populations. TCR usage may significantly influence CD8+ T cell-mediated control of AIDS viruses; however, the potential to modulate the repertoire of functional virus-specific T cells by immunotherapy has not been explored. To investigate this, we analyzed the TCR Vbeta usage of CD8+ T cells populations which were expanded following vaccination with modified vaccinia virus Ankara expressing a HIV-1 gag/multiepitope immunogen (MVA.HIVA) in HIV-1-infected patients receiving highly active antiretroviral therapy. Vaccinations induced the re-expansion of HIV-1-specific CD8+ T cells and these showed broad TCR Vbeta usage which was maintained for at least 1 year in some individuals. By contrast, virus-specific CD8+ T cell populations in the same donors which failed to expand after vaccination and in unvaccinated controls were oligoclonal. Simultaneously, we observed that CD8+ T cells recognizing vaccine-derived HIV-1 epitopes displayed enhanced capacity to proliferate and to inhibit HIV-1 replication in vitro, following MVA.HIVA immunizations. Taken together, these data indicate that an attenuated viral-vectored vaccine can modulate adaptive CD8+ T cell responses to HIV-1 and improve their antiviral functional capacity. The potential therapeutic benefit of this vaccination approach warrants further investigation.

Lühn K, Simmons CP, Moran E, Dung NTP, Chau TNB, Quyen NTH, Thao LTT, Van Ngoc T, Dung NM, Wills B et al. 2007. Increased frequencies of CD4+ CD25(high) regulatory T cells in acute dengue infection. J Exp Med, 204 (5), pp. 979-985. | Show Abstract | Read more

Dengue virus infection is an increasingly important tropical disease, causing 100 million cases each year. Symptoms range from mild febrile illness to severe hemorrhagic fever. The pathogenesis is incompletely understood, but immunopathology is thought to play a part, with antibody-dependent enhancement and massive immune activation of T cells and monocytes/macrophages leading to a disproportionate production of proinflammatory cytokines. We sought to investigate whether a defective population of regulatory T cells (T reg cells) could be contributing to immunopathology in severe dengue disease. CD4(+)CD25(high)FoxP3(+) T reg cells of patients with acute dengue infection of different severities showed a conventional phenotype. Unexpectedly, their capacity to suppress T cell proliferation and to secrete interleukin-10 was not altered. Moreover, T reg cells suppressed the production of vasoactive cytokines after dengue-specific stimulation. Furthermore, T reg cell frequencies and also T reg cell/effector T cell ratios were increased in patients with acute infection. A strong indication that a relative rise of T reg cell/effector T cell ratios is beneficial for disease outcome comes from patients with mild disease in which this ratio is significantly increased (P < 0.0001) in contrast to severe cases (P = 0.2145). We conclude that although T reg cells expand and function normally in acute dengue infection, their relative frequencies are insufficient to control the immunopathology of severe disease.

Gillespie GMA, Bashirova A, Dong T, McVicar DW, Rowland-Jones SL, Carrington M. 2007. Lack of KIR3DS1 binding to MHC class I Bw4 tetramers in complex with CD8+ T cell epitopes. AIDS Res Hum Retroviruses, 23 (3), pp. 451-455. | Show Abstract | Read more

In HIV-1 infection, the synergistic association of a subset of Bw4 MHC class I molecules and the activating killer inhibitory receptor (KIR), KIR3DS1, with prolonged AIDS-free survival has been reported. As KIRs represent a diverse group of MHC class I receptors, we questioned whether Bw4 MHC class I molecules expressing isoleucine at position 80 (Bw4Ile80) and in complex with HIV-1-derived T cell epitopes represented KIR3DS1 ligands. MHC class I tetramers are powerful tools for the detection of T cell receptor-MHC class I interactions, and have recently been used to evaluate KIR-MHC class I binding ex vivo. Specifically, this approach has been successfully utilized to assess binding of Bw4 MHC class I tetramers to KIR3DL1, an inhibitory KIR and allele of KIR3DS1. In this study we generated a diverse panel of HIV-1-specific Bw4Ile80 MHC class I tetramers and tested its ability to bind transiently expressed KIR3DS1 on 293-T cells. Using flow cytometry analysis, the expression of KIR3DS1 on 293-T cells was confirmed by anti-FLAG BioM2 staining, prior to incubation with PE-conjugated MHC class I tetramers. Despite choosing a broad array of peptide epitopes and diverse Bw4Ile80 MHC class I molecules, we were unable to detect tetramer binding to KIR3DS1. We speculate that our negative finding may be a consequence of the MHC class I molecules and peptide epitopes chosen, but could also relate to key amino acid differences that distinguish KIR3DS1 from KIR3DL1.

Reinis M, Weiser B, Kuiken C, Dong T, Lang D, Nachman S, Zhang Y, Rowland-Jones S, Burger H. 2007. Genomic analysis of HIV type 1 strains derived from a mother and child pair of long-term nonprogressors. AIDS Res Hum Retroviruses, 23 (2), pp. 309-315. | Show Abstract | Read more

To investigate the viral features of long-term nonprogressive HIV-1 infection and the selection of viral genomes, we studied serial complete HIV-1 sequences obtained from a mother-child pair, both long-term nonprogressors. Analysis of four genomic sequences demonstrated that all viral genes were intact, lacking major deletions or premature stop codons to easily explain the slow disease progression. These data suggest that viral attenuation, if present, was caused by subtle sequence variations or virus-host interactions. Serial sequences from an HIV-1-infected mother-child pair afforded us the opportunity to examine the immune selection of HIV-1 sequences years after transmission between individuals. We demonstrated that the daughter's strains were most likely subjected to immunoselection or immunoediting according to the presence of novel MHC class I alleles that differed between mother and daughter. An analysis of nef-specific cytotoxic T-lymphocyte responses in the child, whose HIV-1 nef sequence differed from the maternal nef, supported this interpretation. This study highlights the potential of full genome analysis in the investigation of pathogenesis and immune selection during HIV-1 evolution.

Reinis M, Weiser B, Kuiken C, Dong T, Lang D, Nachman S, Zhang Y, Rowland-Jones S, Burger H. 2007. Genomic analysis of HIV type 1 strains derived from a mother and child pair of long-term nonprogressors AIDS RESEARCH AND HUMAN RETROVIRUSES, 23 (2), pp. 309-315. | Read more

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Leligdowicz A, Yindom LM, Onyango C, Sarge-Njie R, Alabi A, Cotten M, Vincent T, Da Costa C, Aaby P, Jaye A et al. 2007. Robust Gag-specific T cell responses characterize viremia control in HIV-2 infection Journal of Clinical Investigation, 117 (10), pp. 3067-3074. | Show Abstract | Read more

HIV-2 infection in the majority of infected subjects follows an attenuated disease course that distinguishes it from infection with HIV-1. Antigen-specific T cells are pivotal in the management of chronic viral infections but are not sufficient to control viral replication in HIV-1-positive subjects, and their function in HIV-2 infection is not fully established. In a community-based cohort of HIV-2 long-term nonprogressors in rural Guinea-Bissau, we performed what we believe is the first comprehensive analysis of HIV-2-specific immune responses. We demonstrate that Gag is the most immunogenic protein. The magnitude of the IFN-γ immune response to the HIV-2 proteome was inversely correlated with HIV-2 viremia, and this relationship was specifically due to the targeting of Gag. Furthermore, patients with undetectable viremia had greater Gag-specific responses compared with patients with high viral replication. The most frequently recognized peptides clustered within a defined region of Gag, and responses to a single peptide in this region were associated with low viral burden. The consistent relationship between Gag-specific immune responses and viremia control suggests that T cell responses are vital in determining the superior outcome of HIV-2 infection. A better understanding of how HIV-2 infection is controlled may identify correlates of effective protective immunity essential for the design of HIV vaccines.

Thananchai H, Gillespie G, Martin MP, Bashirova A, Yawata N, Yawata M, Easterbrook P, McVicar DW, Maenaka K, Parham P et al. 2007. Cutting Edge: Allele-specific and peptide-dependent interactions between KIR3DL1 and HLA-A and HLA-B. J Immunol, 178 (1), pp. 33-37. | Show Abstract

Although it is clear that KIR3DL1 recognizes Bw4(+) HLA-B, the role of Bw4(+) HLA-A allotypes as KIR3DL1 ligands is controversial. We therefore examined the binding of tetrameric HLA-A and -B complexes, including HLA*2402, a common Bw4(+) HLA-A allotype, to KIR3DL1*001, *005, *007, and *1502 allotypes. Only Bw4(+) tetramers bound KIR3DL1. Three of four HLA-A*2402 tetramers bound one or more KIR3DL1 allotypes and all four KIR3DL1 allotypes bound to one or more HLA-A*2402 tetramers, but with different binding specificities. Only KIR3DL1*005 bound both HLA-A*2402 and HLA-B*5703 tetramers. HLA-A*2402-expressing target cells were resistant to lysis by NK cells expressing KIR3DL1*001 or *005. This study shows that HLA-A*2402 is a ligand for KIR3DL1 and demonstrates how the binding of KIR3DL1 to Bw4(+) ligands depends upon the bound peptide as well as HLA and KIR3DL1 polymorphism.

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Dong T, Moran E, Vinh Chau N, Simmons C, Luhn K, Peng Y, Wills B, Phuong Dung N, Thi Thu Thao L, Hien TT et al. 2007. High pro-inflammatory cytokine secretion and loss of high avidity cross-reactive cytotoxic T-cells during the course of secondary dengue virus infection PLoS ONE, 2 (12), | Show Abstract | Read more

Background: Dengue is one of the most important human diseases transmitted by an arthropod vector and the incidence of dengue virus infection has been increasing - over half the world's population now live in areas at risk of infection. Most infections are asymptomatic, but a subset of patients experience a potentially fatal shock syndrome characterised by plasma leakage. Severe forms of dengue are epidemiologically associated with repeated infection by more than one of the four dengue virus serotypes. Generally attributed to the phenomenon of antibody-dependent enhancement, recent observations indicate that T-cells may also influence disease phenotype. Methods and Findings: Virus-specific cytotoxic T lymphocytes (CTL) showing high level cross reactivity between dengue serotypes could be expanded from blood samples taken during the acute phase of secondary dengue infection. These could not be detected in convalescence when only CTL populations demonstrating significant serotype specificity were identified. Dengue cross-reactive CTL clones derived from these patients were of higher avidity than serotype-specific clones and produced much higher levels of both type 1 and certain type 2 cytokines, many previously implicated in dengue pathogenesis. Conclusion: Dengue serotype cross-reactive CTL clones showing high avidity for antigen produce higher levels of inflammatory cytokines than serotype-specific clones. That such cells cannot be expanded from convalescent samples suggests that they maybe depleted, perhaps as a consequence of activation-induced cell death. Such high avidity cross-reactive memory CTL may produce inflammatory cytokines during the course of secondary infection, contributing to the pathogenesis of vascular leak. These cells appear to be subsequently deleted leaving a more serotype-specific memory CTL pool. Further studies are needed to relate these cellular observations to disease phenotype in a large group of patients. If confirmed they have significant implications for understanding the role of virus-specific CTL in pathogenesis of dengue disease. © 2007 Dong et al.

Dong T, Moran E, Vinh Chau N, Simmons C, Luhn K, Peng Y, Wills B, Phuong Dung N, Thi Thu Thao L, Hien TT et al. 2007. High pro-inflammatory cytokine secretion and loss of high avidity cross-reactive cytotoxic T-cells during the course of secondary dengue virus infection. PLoS One, 2 (12), pp. e1192. | Show Abstract | Read more

BACKGROUND: Dengue is one of the most important human diseases transmitted by an arthropod vector and the incidence of dengue virus infection has been increasing - over half the world's population now live in areas at risk of infection. Most infections are asymptomatic, but a subset of patients experience a potentially fatal shock syndrome characterised by plasma leakage. Severe forms of dengue are epidemiologically associated with repeated infection by more than one of the four dengue virus serotypes. Generally attributed to the phenomenon of antibody-dependent enhancement, recent observations indicate that T-cells may also influence disease phenotype. METHODS AND FINDINGS: Virus-specific cytotoxic T lymphocytes (CTL) showing high level cross reactivity between dengue serotypes could be expanded from blood samples taken during the acute phase of secondary dengue infection. These could not be detected in convalescence when only CTL populations demonstrating significant serotype specificity were identified. Dengue cross-reactive CTL clones derived from these patients were of higher avidity than serotype-specific clones and produced much higher levels of both type 1 and certain type 2 cytokines, many previously implicated in dengue pathogenesis. CONCLUSION: Dengue serotype cross-reactive CTL clones showing high avidity for antigen produce higher levels of inflammatory cytokines than serotype-specific clones. That such cells cannot be expanded from convalescent samples suggests that they may be depleted, perhaps as a consequence of activation-induced cell death. Such high avidity cross-reactive memory CTL may produce inflammatory cytokines during the course of secondary infection, contributing to the pathogenesis of vascular leak. These cells appear to be subsequently deleted leaving a more serotype-specific memory CTL pool. Further studies are needed to relate these cellular observations to disease phenotype in a large group of patients. If confirmed they have significant implications for understanding the role of virus-specific CTL in pathogenesis of dengue disease.

Létourneau S, Im E-J, Mashishi T, Brereton C, Bridgeman A, Yang H, Dorrell L, Dong T, Korber B, McMichael AJ, Hanke T. 2007. Design and pre-clinical evaluation of a universal HIV-1 vaccine. PLoS One, 2 (10), pp. e984. | Show Abstract | Read more

BACKGROUND: One of the big roadblocks in development of HIV-1/AIDS vaccines is the enormous diversity of HIV-1, which could limit the value of any HIV-1 vaccine candidate currently under test. METHODOLOGY AND FINDINGS: To address the HIV-1 variation, we designed a novel T cell immunogen, designated HIV(CONSV), by assembling the 14 most conserved regions of the HIV-1 proteome into one chimaeric protein. Each segment is a consensus sequence from one of the four major HIV-1 clades A, B, C and D, which alternate to ensure equal clade coverage. The gene coding for the HIV(CONSV) protein was inserted into the three most studied vaccine vectors, plasmid DNA, human adenovirus serotype 5 and modified vaccine virus Ankara (MVA), and induced HIV-1-specific T cell responses in mice. We also demonstrated that these conserved regions prime CD8(+) and CD4(+) T cell to highly conserved epitopes in humans and that these epitopes, although usually subdominant, generate memory T cells in patients during natural HIV-1 infection. SIGNIFICANCE: Therefore, this vaccine approach provides an attractive and testable alternative for overcoming the HIV-1 variability, while focusing T cell responses on regions of the virus that are less likely to mutate and escape. Furthermore, this approach has merit in the simplicity of design and delivery, requiring only a single immunogen to provide extensive coverage of global HIV-1 population diversity.

Nguyen D, Dong T, Nguyen VVC, Nguyen MD, Wills B, Rowland-Jones S, Farrar J, Simmons C. 2006. Spectrum and kinetic of T cell responses to dengue virus epitopes and the influence of hla polymorphisms in dengue disease pathogenesis AMERICAN JOURNAL OF TROPICAL MEDICINE AND HYGIENE, 75 (5), pp. 289-290.

Ondondo BO, Yang H, Dong T, di Gleria K, Suttill A, Conlon C, Brown D, Williams P, Rowland-Jones SL, Hanke T et al. 2006. Immunisation with recombinant modified vaccinia virus Ankara expressing HIV-1 gag in HIV-1-infected subjects stimulates broad functional CD4+ T cell responses. Eur J Immunol, 36 (10), pp. 2585-2594. | Show Abstract | Read more

Virus-specific CD4+ T cells with IL-2-secreting and/or proliferative capacity are detected readily in HIV-1-infected long-term nonprogressors and rarely in persons with untreated progressive infection. The contribution of these cells to viraemia control is uncertain, but this question might be addressed in clinical therapeutic vaccination studies. However, the quality of T helper responses induced by currently available HIV-1 vaccine candidates has not been explored in depth. We determined the effect of vaccination with modified vaccinia virus Ankara (MVA) expressing HIV-1 gag p24/p17 (MVA.HIVA) on HIV-1-specific CD4+ T cell responses in 16 chronically infected, highly active antiretroviral therapy (HAART)-treated subjects using CD8-depleted IFN-gamma ELISPOT assays, intracellular cytokine staining assays for IL-2 and IFN-gamma, and a CFSE-based proliferation assay. Gag-specific CD4+ T cell responses were significantly increased in magnitude and breadth after vaccination and targeted both known and new epitopes, several of which were also recognised by healthy HIV-uninfected volunteers immunised with the same vaccines. The frequencies of CD4+ T cells expressing IL-2 or IFN-gamma, alone or simultaneously, were also augmented. These findings indicate that functional virus-specific T helper cells can be boosted by vaccination in chronic HIV-1 infection. Further evaluation of their role in viraemia control is warranted.

Rowland-Jones S, Dong T. 2006. HIV: tired T cells turn around. Nature, 443 (7109), pp. 282-283. | Show Abstract | Read more

HIV-1 prompts a massive cellular immune response, but eventually it tires the immune cells. Blocking the activation of a cell receptor called PD-1 might restore these exhausted cells. © 2006 Nature Publishing Group.

Rowland-Jones S, Dong T. 2006. HIV - Tired T cells turn around NATURE, 443 (7109), pp. 282-283. | Read more

Gillespie GMA, Stewart-Jones G, Rengasamy J, Beattie T, Bwayo JJ, Plummer FA, Kaul R, McMichael AJ, Easterbrook P, Dong T et al. 2006. Strong TCR conservation and altered T cell cross-reactivity characterize a B*57-restricted immune response in HIV-1 infection. J Immunol, 177 (6), pp. 3893-3902. | Show Abstract

HLA-B*57 is associated with slower disease progression to AIDS, and CD8+ T cell responses to B*57-restricted epitopes are thought to contribute to this protective effect. In this study, we evaluate the B*57-restricted p24 KAFSPEVIPMF (KF11) immune response which is immunodominant during chronic infection. Previously, we observed that the KF11 clade variants KGFNPEVIPMF [A2G,S4N] and KAFNPEIIMPF [S4N,V7I], sharing a position 4 mutation, are differentially recognized by KF11-specific T cells. By combining structural and cellular studies, we now demonstrate that the KF11 and [A2G,S4N] epitopes induce distinct functional responses in [A2G,S4N] and KF11-specific T cells, respectively, despite minimal structural differences between the individual B*57-peptide complexes. Recently, we also elucidated the highly distinct structure of KF11 in complex with B*5703, and have now characterized the CD8+ T cell repertoire recognizing this epitope. We now report striking features of TCR conservation both in terms of TCR Valpha and Vbeta chain usage, and throughout the hypervariable region. Collectively, our findings highlight unusual features of the B*5701/B*5703-KF11-specific immune responses which could influence disease progression and that might be important to consider when designing future vaccine regimens.

Duvall MG, Jaye A, Dong T, Brenchley JM, Alabi AS, Jeffries DJ, van der Sande M, Togun TO, McConkey SJ, Douek DC et al. 2006. Maintenance of HIV-specific CD4+ T cell help distinguishes HIV-2 from HIV-1 infection. J Immunol, 176 (11), pp. 6973-6981. | Show Abstract

Unlike HIV-1-infected people, most HIV-2-infected subjects maintain a healthy CD4+ T cell count and a strong HIV-specific CD4+ T cell response. To define the cellular immunological correlates of good prognosis in HIV-2 infection, we conducted a cross-sectional study of HIV Gag-specific T cell function in HIV-1- and HIV-2-infected Gambians. Using cytokine flow cytometry and lymphoproliferation assays, we show that HIV-specific CD4+ T cells from HIV-2-infected individuals maintained proliferative capacity, were not terminally differentiated (CD57-), and more frequently produced IFN-gamma or IL-2 than CD4+ T cells from HIV-1-infected donors. Polyfunctional (IFN-gamma+/IL-2+) HIV-specific CD4+ T cells were found exclusively in HIV-2+ donors. The disparity in CD4+ T cell responses between asymptomatic HIV-1- and HIV-2-infected subjects was not associated with differences in the proliferative capacity of HIV-specific CD8+ T cells. This study demonstrates that HIV-2-infected donors have a well-preserved and functionally heterogeneous HIV-specific memory CD4+ T cell response that is associated with delayed disease progression in the majority of infected people.

Dorrell L, Yang H, Ondondo B, Dong T, di Gleria K, Suttill A, Conlon C, Brown D, Williams P, Bowness P et al. 2006. Expansion and diversification of virus-specific T cells following immunization of human immunodeficiency virus type 1 (HIV-1)-infected individuals with a recombinant modified vaccinia virus Ankara/HIV-1 Gag vaccine. J Virol, 80 (10), pp. 4705-4716. | Show Abstract | Read more

Affordable therapeutic strategies that induce sustained control of human immunodeficiency virus type 1 (HIV-1) replication and are tailored to the developing world are urgently needed. Since CD8(+) and CD4(+) T cells are crucial to HIV-1 control, stimulation of potent cellular responses by therapeutic vaccination might be exploited to reduce antiretroviral drug exposure. However, therapeutic vaccines tested to date have shown modest immunogenicity. In this study, we performed a comprehensive analysis of the changes in virus-specific CD8(+) and CD4(+) T-cell responses occurring after vaccination of 16 HIV-1-infected individuals with a recombinant modified vaccinia virus Ankara-vectored vaccine expressing the consensus HIV-1 clade A Gag p24/p17 sequences and multiple CD8(+) T-cell epitopes during highly active antiretroviral therapy. We observed significant amplification and broadening of CD8(+) and CD4(+) gamma interferon responses to vaccine-derived epitopes in the vaccinees, without rebound viremia, but not in two unvaccinated controls followed simultaneously. Vaccine-driven CD8(+) T-cell expansions were also detected by tetramer reactivity, predominantly in the CD45RA(-) CCR7(+) or CD45RA(-) CCR7(-) compartments, and persisted for at least 1 year. Expansion was associated with a marked but transient up-regulation of CD38 and perforin within days of vaccination. Gag-specific CD8(+) and CD4(+) T-cell proliferation also increased postvaccination. These data suggest that immunization with MVA.HIVA is a feasible strategy to enhance potentially protective T-cell responses in individuals with chronic HIV-1 infection.

Chakraborty R, Reinis M, Rostron T, Philpott S, Dong T, D'Agostino A, Musoke R, Silva E, Stumpf M, Weiser B et al. 2006. nef gene sequence variation among HIV-1-infected African children. HIV Med, 7 (2), pp. 75-84. | Show Abstract | Read more

BACKGROUND: There are few data on African children infected with nonclade B HIV-1 in endemic settings, which limits generalizations about pathogenesis and progression. Genotypic and phenotypic variations in host immunogenetics and HIV-1 negative factor (nef) accessory protein may influence disease progression and have frequently been characterized in subjects infected with clade B HIV-1. METHODS: In this descriptive study, we report nef gene sequence variation and host genetic polymorphisms in 32 Kenyan children, including 12 slow progressors. RESULTS: Phylogenetic analysis identified HIV-1 clades A, C and D and a recombinant A/D subtype. Grossly defective nef genes or significant changes from relevant clade reference sequences were not identified in children with delayed disease progression. CONCLUSIONS: nef sequence variations may not be common in perinatally infected African children. Further studies are warranted in HIV-1-infected subjects in settings where infection is endemic.

Iversen AKN, Stewart-Jones G, Learn GH, Christie N, Sylvester-Hviid C, Armitage AE, Kaul R, Beattie T, Lee JK, Li Y et al. 2006. Conflicting selective forces affect T cell receptor contacts in an immunodominant human immunodeficiency virus epitope. Nat Immunol, 7 (2), pp. 179-189. | Show Abstract | Read more

Cytotoxic T lymphocytes (CTLs) are critical for the control of human immunodeficiency virus, but containment of virus replication can be undermined by mutations in CTL epitopes that lead to virus escape. We analyzed the evolution in vivo of an immunodominant, HLA-A2-restricted CTL epitope and found two principal, diametrically opposed evolutionary pathways that exclusively affect T cell-receptor contact residues. One pathway was characterized by acquisition of CTL escape mutations and the other by selection for wild-type amino acids. The pattern of CTL responses to epitope variants shaped which variant(s) prevailed in the virus population. The pathways notably influenced the amount of plasma virus, as patients with efficient CTL selection had lower plasma viral loads than did patients without efficient selection. Thus, viral escape from CTL responses does not necessarily correlate with disease progression.

Leligdowicz A, Yindom L-M, Jaye A, Dong T, Alabi A, Sarge-N'jie R, Njai H, McMichael A, Whittle H, Rowland-Jones S. 2006. HIV-2 gene product-specific T cell responses and viraemia control RETROVIROLOGY, 3

Ondondo B, Yang H, Dong T, de Gleria K, Suttill A, Conlon C, Brown D, Williams P, Bowness P, Rowland-Jones SL et al. 2006. Detection of broad functional gag-specific CD4+T cell responses in HIV-1-infected subjects following therapeutic immunization with rMVA expressing an HIV-1 gag immunogen RETROVIROLOGY, 3

Ranasinghe SR, Abidi SH, Rowland-Jones SL, McMichael AJ, Dong T, Davis SJ. 2005. Functional analysis of candidate CD8+T cell-derived anti-HIV factors IMMUNOLOGY, 116 pp. 80-80.

Dorrell L, Yang H, Iversen AK, Conlon C, Suttill A, Lancaster M, Dong T, Cebere I, Edwards A, Rowland-Jones S et al. 2005. Therapeutic immunization of highly active antiretroviral therapy-treated HIV-1-infected patients: safety and immunogenicity of an HIV-1 gag/poly-epitope DNA vaccine. AIDS, 19 (12), pp. 1321-1323. | Show Abstract | Read more

In view of the global emergency posed by lack of access to highly active antiretroviral therapy (HAART) and the limitations of current drug regimens, alternative therapeutic strategies are urgently needed. Cellular immune responses elicited by HIV-1 exert some control over virus replication, therefore the enhancement of HIV-1-specific responses by therapeutic vaccination might lead to viral containment without HAART. We evaluated the safety and immunogenicity, in HIV-1-infected individuals under HAART suppression, of a DNA vaccine, pTHr.HIVA.

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Lohman BL, Slyker JA, Richardson BA, Farquhar C, Mabuka JM, Crudder C, Dong T, Obimbo E, Mbori-Ngacha D, Overbaugh J et al. 2005. Longitudinal assessment of human immunodeficiency virus type 1 (HIV-1)-specific gamma interferon responses during the first year of life in HIV-1-infected infants JOURNAL OF VIROLOGY, 79 (13), pp. 8121-8130. | Show Abstract | Read more

Human immunodeficiency virus type 1 (HIV-1) infection results in different patterns of viral replication in pediatric compared to adult populations. The role of early HIV-1-specific responses in viral control has not been well defined, because most studies of HIV-1-infected infants have been retrospective or cross-sectional. We evaluated the association between HIV-1-specific gamma interferon (IFN-γ) release from the cells of infants of 1 to 3 months of age and peak viral loads and mortality in the first year of life among 61 Kenyan HIV-1-infected infants. At 1 month, responses were detected in 7/12 (58%) and 6/21 (29%) of infants infected in utero and peripartum, respectively (P = 0.09), and in ∼50% of infants thereafter. Peaks of HIV-specific spot-forming units (SFU) increased significantly with age in all infants, from 251/10 6 peripheral blood mononuclear cells (PBMC) at 1 month of age to 501/10 6 PBMC at 12 months of age (P = 0.03), although when limited to infants who survived to 1 year, the increase in peak HIV-specific SFU was no longer significant (P = 0.18). Over the first year of life, infants with IFN-γ responses at 1 month had peak plasma viral loads, rates of decline of viral load, and mortality risk similar to those of infants who lacked responses at 1 month. The strength and breadth of IFN-γ responses at 1 month were not significantly associated with viral containment or mortality. These results suggest that, in contrast to HIV-1-infected adults, in whom strong cytotoxic T lymphocyte responses in primary infection are associated with reductions in viremia, HIV-1-infected neonates generate HIV-1-specific CD8 + -T-cell responses early in life that are not clearly associated with improved clinical outcomes. Copyright © 2005, American Society for Microbiology. All Rights Reserved.

Chakraborty R, Morel A-S, Sutton JK, Appay V, Ripley RM, Dong T, Rostron T, Ogola S, Palakudy T, Musoke R et al. 2005. Correlates of delayed disease progression in HIV-1-infected Kenyan children. J Immunol, 174 (12), pp. 8191-8199. | Show Abstract

Without treatment most HIV-1-infected children in Africa die before their third birthday (>89%) and long-term nonprogressors are rare. The mechanisms underlying nonprogression in HIV-1-infected children are not well understood. In the present study, we examined potential correlates of delayed HIV disease progression in 51 HIV-1-infected African children. Children were assigned to progression subgroups based on clinical characterization. HIV-1-specific immune responses were studied using a combination of ELISPOT assays, tetramer staining, and FACS analysis to characterize the magnitude, specificity, and functional phenotype of HIV-1-specific CD8(+) and CD4(+) T cells. Host genetic factors were examined by genotyping with sequence-specific primers. HIV-1 nef gene sequences from infecting isolates from the children were examined for potential attenuating deletions. Thymic output was measured by T cell rearrangement excision circle assays. HIV-1-specific CD8(+) T cell responses were detected in all progression groups. The most striking attribute of long-term survivor nonprogressors was the detection of HIV-1-specific CD4(+) Th responses in this group at a magnitude substantially greater than previously observed in adult long-term nonprogressors. Although long-term survivor nonprogressors had a significantly higher percentage of CD45RA(+)CD4(+) T cells, nonprogression was not associated with higher thymic output. No protective genotypes for known coreceptor polymorphisms or large sequence deletions in the nef gene associated with delayed disease progression were identified. In the absence of host genotypes and attenuating mutations in HIV-1 nef, long-term surviving children generated strong CD4(+) T cell responses to HIV-1. As HIV-1-specific helper cells support anti-HIV-1 effector responses in active disease, their presence may be important in delaying disease progression.

Simmons CP, Dong T, Chau NV, Dung NTP, Chau TNB, Thao LTT, Dung NT, Hien TT, Rowland-Jones S, Farrar J. 2005. Early T-cell responses to dengue virus epitopes in Vietnamese adults with secondary dengue virus infections. J Virol, 79 (9), pp. 5665-5675. | Show Abstract | Read more

T-cell responses to dengue viruses may be important in both protective immunity and pathogenesis. This study of 48 Vietnamese adults with secondary dengue virus infections defined the breadth and magnitude of peripheral T-cell responses to 260 overlapping peptide antigens derived from a dengue virus serotype 2 (DV2) isolate. Forty-seven different peptides evoked significant gamma interferon enzyme-linked immunospot (ELISPOT) assay responses in 39 patients; of these, 34 peptides contained potentially novel T-cell epitopes. NS3 and particularly NS3200-324 were important T-cell targets. The breadth and magnitude of ELISPOT responses to DV2 peptides were independent of the infecting dengue virus serotype, suggesting that cross-reactive T cells dominate the acute response during secondary infection. Acute ELISPOT responses were weakly correlated with the extent of hemoconcentration in individual patients but not with the nadir of thrombocytopenia or overall clinical disease grade. NS3556-564 and Env414-422 were identified as novel HLA-A*24 and B*07-restricted CD8+ T-cell epitopes, respectively. Acute T-cell responses to natural variants of Env414-422 and NS3556-564 were largely cross-reactive and peaked during disease convalescence. The results highlight the importance of NS3 and cross-reactive T cells during acute secondary infection but suggest that the overall breadth and magnitude of the T-cell response is not significantly related to clinical disease grade.

Li H, Zhou M, Han J, Zhu X, Dong T, Gao GF, Tien P. 2005. Generation of murine CTL by a hepatitis B virus-specific peptide and evaluation of the adjuvant effect of heat shock protein glycoprotein 96 and its terminal fragments. J Immunol, 174 (1), pp. 195-204. | Show Abstract

Previously, we reported that a 7-mer HLA-A11-restricted peptide (YVNTNMG) of hepatitis B virus (HBV) core Ag (HBcAg(88-94)) was associated with heat shock protein (HSP) gp96 in liver tissues of patients with HBV-induced hepatocellular carcinoma (HCC). This peptide is highly homologous to a human HLA-A11-restricted 9-mer peptide (YVNVNMGLK) and to a mouse H-2-K(d)-restricted 9-mer peptide (SYVNTNMGL). To further characterize its immunogenicity, BALB/c mice were vaccinated with the HBV 7-mer peptide. It was found that a specific CTL response was induced by the 7-mer peptide, although the response was approximately 50% of that induced by the mouse H-2-K(d)-restricted 9-mer peptide, as detected by ELISPOT, tetramer, and (51)Cr release assays. To evaluate the adjuvant effect of HSP gp96, mice were coimmunized with gp96 and the 9-mer peptide, and a significant adjuvant effect was observed with gp96. To further determine whether the immune effect of gp96 was dependent on peptide binding, the N- and C-terminal fragments of gp96, which are believed to contain the putative peptide-binding domain, were cloned and expressed in Escherichia coli. CTL assays indicated that only the N-terminal fragment, but not the C-terminal fragment, was able to produce the adjuvant effect. These results clearly demonstrated the potential of using gp96 or its N-terminal fragment as a possible adjuvant to augment CTL response against HBV infection and HCC.

Dong T, Stewart-Jones G, Chen N, Easterbrook P, Xu X, Papagno L, Appay V, Weekes M, Conlon C, Spina C et al. 2004. HIV-specific cytotoxic T cells from long-term survivors select a unique T cell receptor. J Exp Med, 200 (12), pp. 1547-1557. | Show Abstract | Read more

HIV-specific cytotoxic T lymphocytes (CTL) are important in controlling HIV replication, but the magnitude of the CTL response does not predict clinical outcome. In four donors with delayed disease progression we identified Vbeta13.2 T cell receptors (TCRs) with very similar and unusually long beta-chain complementarity determining region 3 (CDR3) regions in CTL specific for the immunodominant human histocompatibility leukocyte antigens (HLA)-B8-restricted human immunodeficiency virus-1 (HIV-1) nef epitope, FLKEKGGL (FL8). CTL expressing Vbeta13.2 TCRs tolerate naturally arising viral variants in the FL8 epitope that escape recognition by other CTL. In addition, they expand efficiently in vitro and are resistant to apoptosis, in contrast to FL8-specific CTL using other TCRs. Selection of Vbeta13.2 TCRs by some patients early in the FL8-specific CTL response may be linked with better clinical outcome.

Lee JK, Stewart-Jones G, Dong T, Harlos K, Di Gleria K, Dorrell L, Douek DC, van der Merwe PA, Jones EY, McMichael AJ. 2004. T cell cross-reactivity and conformational changes during TCR engagement. J Exp Med, 200 (11), pp. 1455-1466. | Show Abstract | Read more

All thymically selected T cells are inherently cross-reactive, yet many data indicate a fine specificity in antigen recognition, which enables virus escape from immune control by mutation in infections such as the human immunodeficiency virus (HIV). To address this paradox, we analyzed the fine specificity of T cells recognizing a human histocompatibility leukocyte antigen (HLA)-A2-restricted, strongly immunodominant, HIV gag epitope (SLFNTVATL). The majority of 171 variant peptides tested bound HLA-A2, but only one third were recognized. Surprisingly, one recognized variant (SLYNTVATL) showed marked differences in structure when bound to HLA-A2. T cell receptor (TCR) recognition of variants of these two peptides implied that they adopted the same conformation in the TCR-peptide-major histocompatibility complex (MHC) complex. However, the on-rate kinetics of TCR binding were identical, implying that conformational changes at the TCR-peptide-MHC binding interface occur after an initial permissive antigen contact. These findings have implications for the rational design of vaccines targeting viruses with unstable genomes.

Beattie T, Kaul R, Rostron T, Dong T, Easterbrook P, Jaoko W, Kimani J, Plummer F, McMichael A, Rowland-Jones S. 2004. Screening for HIV-specific T-cell responses using overlapping 15-mer peptide pools or optimized epitopes. AIDS, 18 (11), pp. 1595-1598. | Show Abstract | Read more

The IFN-y enzyme-linked immunospot (ELI-Spot) assay is often used to map HIV-specific CD8 T-cell responses. We compared overlapping 15-mer pools with optimized CD8 epitopes to screen ELISpot responses in HIV-infected individuals. The 15-mer pools detected responses to previously undefined epitopes, but often missed low-level responses to predefined epitopes, particularly when the epitope was central in the 15-mer, rather than at the N-terminus or C-terminus. These factors should be considered in the monitoring of HIV vaccine trials.

Hansasuta P, Dong T, Thananchai H, Weekes M, Willberg C, Aldemir H, Rowland-Jones S, Braud VM. 2004. Recognition of HLA-A3 and HLA-A11 by KIR3DL2 is peptide-specific. Eur J Immunol, 34 (6), pp. 1673-1679. | Show Abstract | Read more

The recognition of MHC class I molecules by killer cell immunoglobulin-like receptors (KIR) is central to the control of NK cell function and can also modulate the CTL activation threshold. Among KIR receptors, KIR3DL2 is thought to interact with HLA-A3 and -A11, although direct evidence has been lacking. In this study, we show that HLA-A3 and -A11 tetramers specifically bind to KIR3DL2*001 transfectants and that this recognition is peptide-specific. Single amino acid substitutions in the nonamer peptide underline a critical role for residue 8 in recognition of KIR3DL2. However, the role of this interaction in vivo still remains to be established.

Papagno L, Spina CA, Marchant A, Salio M, Rufer N, Little S, Dong T, Chesney G, Waters A, Easterbrook P et al. 2004. Immune activation and CD8+ T-cell differentiation towards senescence in HIV-1 infection. PLoS Biol, 2 (2), pp. E20. | Show Abstract | Read more

Progress in the fight against the HIV/AIDS epidemic is hindered by our failure to elucidate the precise reasons for the onset of immunodeficiency in HIV-1 infection. Increasing evidence suggests that elevated immune activation is associated with poor outcome in HIV-1 pathogenesis. However, the basis of this association remains unclear. Through ex vivo analysis of virus-specific CD8(+) T-cells and the use of an in vitro model of naïve CD8(+) T-cell priming, we show that the activation level and the differentiation state of T-cells are closely related. Acute HIV-1 infection induces massive activation of CD8(+) T-cells, affecting many cell populations, not only those specific for HIV-1, which results in further differentiation of these cells. HIV disease progression correlates with increased proportions of highly differentiated CD8(+) T-cells, which exhibit characteristics of replicative senescence and probably indicate a decline in T-cell competence of the infected person. The differentiation of CD8(+) and CD4(+) T-cells towards a state of replicative senescence is a natural process. It can be driven by excessive levels of immune stimulation. This may be part of the mechanism through which HIV-1-mediated immune activation exhausts the capacity of the immune system.

Evans EJ, Hene L, Sparks LM, Dong T, Retiere C, Fennelly JA, Manso-Sancho R, Powell J, Braud VM, Rowland-Jones SL et al. 2003. The T cell surface--how well do we know it? Immunity, 19 (2), pp. 213-223. | Show Abstract | Read more

The overall degree of complexity of the T cell surface has been unclear, constraining our understanding of its biology. Using global gene expression analysis, we show that 111 of 374 genes encoding well-characterized leukocyte surface antigens are expressed by a resting cytotoxic T cell. Unexpectedly, of 97 stringently defined, T cell-specific transcripts with unknown functions that we identify, none encode proteins with the modular architecture characteristic of 80% of leukocyte surface antigens. Only two encode proteins with membrane topologies found exclusively in cell surface molecules. Our analysis indicates that the cell type-specific composition of the resting CD8+ T cell surface is now largely defined, providing an insight into the overall compositional complexity of the mammalian cell surface and a framework for formulating systematic models of T cell surface-dependent processes, such as T cell receptor triggering.

Mongkolsapaya J, Dejnirattisai W, Xu X-N, Vasanawathana S, Tangthawornchaikul N, Chairunsri A, Sawasdivorn S, Duangchinda T, Dong T, Rowland-Jones S et al. 2003. Original antigenic sin and apoptosis in the pathogenesis of dengue hemorrhagic fever. Nat Med, 9 (7), pp. 921-927. | Show Abstract | Read more

Dengue virus presents a growing threat to public health in the developing world. Four major serotypes of dengue virus have been characterized, and epidemiological evidence shows that dengue hemorrhagic fever (DHF), the more serious manifestation of the disease, occurs more frequently upon reinfection with a second serotype. We have studied dengue virus-specific T-cell responses in Thai children. During acute infection, few dengue-responsive CD8+ T cells were recovered; most of those present showed an activated phenotype and were undergoing programmed cell death. Many dengue-specific T cells were of low affinity for the infecting virus and showed higher affinity for other, probably previously encountered strains. Profound T-cell activation and death may contribute to the systemic disturbances leading to DHF, and original antigenic sin in the T-cell responses may suppress or delay viral elimination, leading to higher viral loads and increased immunopathology.

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Mongkolsapaya J, Dejnirattisai W, Xu XN, Vasanawathana S, Tangthawornchaikul N, Chairunsri A, Sawasdivorn S, Duangchinda T, Dong T, Rowland-Jones S et al. 2003. Original antigenic sin and apoptosis in the pathogenesis of dengue hemorrhagic fever Nature Medicine, 9 (7), pp. 921-927. | Show Abstract | Read more

Dengue virus presents a growing threat to public health in the developing world. Four major serotypes of dengue virus have been characterized, and epidemiological evidence shows that dengue hemorrhagic fever (DHF), the more serious manifestation of the disease, occurs more frequently upon reinfection with a second serotype. We have studied dengue virus-specific T-cell responses in Thai children. During acute infection, few dengue-responsive CD8 + T cells were recovered; most of those present showed an activated phenotype and were undergoing programmed cell death. Many dengue-specific T cells were of low affinity for the infecting virus and showed higher affinity for other, probably previously encountered strains. Profound T-cell activation and death may contribute to the systemic disturbances leading to DHF, and original antigenic sin in the T-cell responses may suppress or delay viral elimination, leading to higher viral loads and increased immunopathology.

Chakraborty R, Gillespie GMA, Reinis M, Rostron T, Dong T, Philpott S, Burger H, Weiser B, Peto T, Rowland-Jones SL. 2002. HIV-1-specific CD8 T cell responses in a pediatric slow progressor infected as a premature neonate. AIDS, 16 (15), pp. 2085-2087. | Show Abstract | Read more

We describe the long-term survival of an individual infected with HIV-1 during extrauterine life as a premature newborn. In the absence of viral attenuation in the Nef/LTR structure or significant co-receptor polymorphisms, slow progression was associated with the strong HIV-1-specific broadly cross-reactive CD8 T cell responses. HIV-1 infection as early as 25 weeks' gestation may thus results in the development of immune responses that control viral replication and lead to prolonged survival.

Bird TG, Kaul R, Rostron T, Kimani J, Embree J, Dunn PP, Bwayo JJ, Plummer FA, Rowland-Jones SL, Dong T, Oxford-Nairobi HLA Collaborative Group. 2002. HLA typing in a Kenyan cohort identifies novel class I alleles that restrict cytotoxic T-cell responses to local HIV-1 clades. AIDS, 16 (14), pp. 1899-1904. | Show Abstract | Read more

OBJECTIVES: To investigate HLA class I allele frequencies in a Kenyan commercial sex worker (CSW) cohort, and to examine HIV-1 specific cytotoxic T lymphocyte (CTL) responses directed against epitopes derived from locally prevalent clade A virus. METHODS: PCR-single strand polymorphism HLA class I typing. Sequencing of novel alleles and examination of their distribution in the CSW cohort, and a low risk HIV uninfected cohort. The peptide-binding motif of a novel class I allele was predicted, and a panel of candidate CTL epitopes was synthesized whose functional significance was examined using ELISpot and Cr release assays. RESULTS: Class I HLA-A and B frequencies within the cohort are presented. Two novel class I alleles were found, HLA-B*4415 and HLA-Cw*0407. These two class I alleles were relatively common, both in the CSW cohort (2.1% and 3.3% respectively) and in a cohort of lower risk women (1.9% and 3.8% respectively). Allele HLA-B*4415 restricted CTL responses against a novel epitope (EEKAFSPEV) derived from p24 of clade A HIV-1, and HLA-Cw0407 restricted CTL against a predefined HLA-Cw*0401 gp120 epitope. CONCLUSIONS: Multi-epitope vaccine design requires knowledge of HLA class I distribution and HIV CTL epitope characterization in potential target populations. The description of two novel HLA class I alleles at high frequency in this high risk Kenyan CSW cohort suggests that HLA mapping of vaccine cohorts and subsequent characterization of local CTL epitopes will be warranted prior to vaccine trials.

Kaul R, Rowland-Jones SL, Gillespie G, Kimani J, Dong T, Kiama P, Simonsen JN, Bwayo JJ, McMichael AJ, Plummer FA. 2002. Gonococcal cervicitis is associated with reduced systemic CD8+ T cell responses in human immunodeficiency virus type 1-infected and exposed, uninfected sex workers. J Infect Dis, 185 (10), pp. 1525-1529. | Show Abstract | Read more

Neisseria gonorrhoeae cervicitis and human immunodeficiency virus (HIV) type 1 frequently coinfect core transmitter populations, such as female sex workers. Gonococcal cervicitis is associated with increased viral shedding and plasma viremia in HIV-1-infected women and increased HIV-1 susceptibility in uninfected women. We studied the influence of gonococcal cervicitis on CD8(+) interferon (IFN)-gamma responses to HIV-1 and cytomegalovirus (CMV) epitopes in HIV-1-infected and in highly-exposed, persistently seronegative (HEPS) female sex workers. In HIV-1-infected women, gonococcal cervicitis was associated with reduced IFN-gamma responses in bulk CD8(+) lymphocyte populations, and intracellular cytokine staining, combined with class I major histocompatibility complex (MHC)-peptide tetramer studies, demonstrated reduced IFN-gamma production by HIV-1 epitope-specific CD8(+) lymphocytes. In HEPS sex workers, cervicitis was associated with the transient loss of systemic HIV-1-specific CD8(+) responses and with reduced function of CMV-specific CD8(+) lymphocytes. Impaired function of virus-specific CD8(+) lymphocytes may partly explain the deleterious effects of gonococcal cervicitis on HIV-1 immune control and susceptibility.

Gillespie GMA, Kaul R, Dong T, Yang H-B, Rostron T, Bwayo JJ, Kiama P, Peto T, Plummer FA, McMichael AJ, Rowland-Jones SL. 2002. Cross-reactive cytotoxic T lymphocytes against a HIV-1 p24 epitope in slow progressors with B*57. AIDS, 16 (7), pp. 961-972. | Show Abstract | Read more

OBJECTIVES: To determine whether CD8 T lymphocytes from HIV-1-infected patients expressing B*5701 and B*5703 show broad cross-reactivity against different variants of a conserved p24 epitope, which might account for the good prognosis of HIV-1-infected individuals with HLA-B*57. DESIGN: B*5701+ and B*5703+ were recruited from Nairobi, Kenya and from Oxford, UK. All patients had been HIV positive for at least 8 years and could be categorized as slow progressors. METHODS: CD8 cytotoxic T cell clones were generated from B*5701+ and B*5703+ donors and tested for their ability to recognize clade variants of an index p24 epitope in standard cytolytic assays. Cross-reactive responses in freshly isolated peripheral blood mononuclear cells (PBMC) were assessed by interferon-gamma (IFNgamma) production and tetramer binding. RESULTS: Broad cross-clade reactivity for both cytolysis and tetramer binding was observed in CD8 T cell clones from patients harbouring the index epitope sequence. Patterns of cross-reactivity were similar in freshly isolated PBMC but varied between individuals in terms of strength and breath of responses generated. One common variant induced an unusual response with tetramer binding but often failed to induce IFNgamma production, and another was a weak stimulator of both IFNgamma and cytolytic activity. CONCLUSION: B*5701+ and B5703+ donors demonstrate broad functional cross-reactivity to both common and rare variants of a dominant p24 epitope, which could be relevant to the association of B*57 alleles with slow progression to AIDS.

John GC, Bird T, Overbaugh J, Nduati R, Mbori-Ngacha D, Rostron T, Dong T, Kostrikis L, Richardson B, Rowland-Jones SL. 2001. CCR5 promoter polymorphisms in a Kenyan perinatal human immunodeficiency virus type 1 cohort: association with increased 2-year maternal mortality. J Infect Dis, 184 (1), pp. 89-92. | Show Abstract | Read more

The CCR5 chemokine receptor acts as a coreceptor with CD4 to permit infection by primary macrophage-tropic human immunodeficiency virus type 1 (HIV-1) strains. The CCR5Delta32 mutation, which is associated with resistance to infection in homozygous individuals and delayed disease progression in heterozygous individuals, is rare in Africa, where the HIV-1 epidemic is growing rapidly. Several polymorphisms in the promoter region of CCR5 have been identified, the clinical and functional relevance of which remain poorly defined. We evaluated the effect of 4 CCR5 promoter mutations on systemic and mucosal HIV-1 replication, disease progression, and perinatal transmission in a cohort of 276 HIV-1-seropositive women in Nairobi, Kenya. Mutations at positions 59353, 59402, and 59029 were not associated with effects on mortality, virus load, genital shedding, or transmission in this cohort. However, women with the 59356 C/T genotype had a 3.1-fold increased risk of death during the 2-year follow-up period (95% confidence interval [CI], 1.0-9.5) and a significant increase in vaginal shedding of HIV-1-infected cells (odds ratio, 2.1; 95% CI, 1.0-4.3), compared with women with the 59356 C/C genotype.

Kaul R, Dong T, Plummer FA, Kimani J, Rostron T, Kiama P, Njagi E, Irungu E, Farah B, Oyugi J et al. 2001. CD8(+) lymphocytes respond to different HIV epitopes in seronegative and infected subjects. J Clin Invest, 107 (10), pp. 1303-1310. | Show Abstract | Read more

HIV-1-specific cytotoxic T-lymphocyte (CTL) responses have been detected at a low frequency in many HIV-1-exposed, persistently seronegative (HEPS) subjects. However, it is unclear how CTLs could protect against HIV acquisition in HEPS subjects, when high levels of circulating CTL fail to prevent disease progression in most seropositive subjects. To address this issue we studied CD8(+) lymphocyte responses to a panel of HIV-1 CTL epitopes in 91 HEPS and 87 HIV-1-infected Nairobi sex workers. HIV-specific responses in seropositive women focused strongly on epitopes rarely or never recognized in HEPS subjects, who targeted epitopes that were subdominant or unrecognized in infected women. These differences in epitope specificity were restricted by only those HLA class I alleles that are associated with a reduced risk of HIV-1 infection in this cohort. Late seroconversion in HEPS donors was associated with a switch in epitope specificity and/or immunodominance to those epitopes preferentially recognized by HIV-1-infected women. The likelihood of detecting HIV-1-specific responses in HEPS women increased with the duration of viral exposure, suggesting that HIV-1-specific CD8(+) responses are acquired over time. The association between differential recognition of distinct CTL epitopes and protection from HIV-1 infection may have significant implications for vaccine design.

Kaul R, Rowland-Jones SL, Kimani J, Dong T, Yang HB, Kiama P, Rostron T, Njagi E, Bwayo JJ, MacDonald KS et al. 2001. Late seroconversion in HIV-resistant Nairobi prostitutes despite pre-existing HIV-specific CD8+ responses. J Clin Invest, 107 (3), pp. 341-349. | Show Abstract | Read more

Resistance to HIV infection in a small group of Kenyan sex workers is associated with CD8+-lymphocyte responses to HIV cytotoxic T-lymphocyte (CTL) epitopes. Eleven prostitutes meeting criteria for HIV resistance seroconverted between 1996 and 1999. The occurrence and specificity of preexisting HIV-1 epitope-specific responses were examined using the IFN-gamma enzyme-linked immunospot assay, and any epitopes recognized were cloned and sequenced from the infecting viral isolate. Immunologic and behavioral variables were compared between late seroconverters and persistently uninfected sex worker controls. HIV-1 CTL epitope responses were present in four of six cases, 5-18 months before seroconversion, and their presence was confirmed by bulk CTL culture. A possible viral escape mutation was found in one of six epitopes. The key epidemiologic correlate of late seroconversion was a reduction in sex work over the preceding year. In persistently uninfected controls, a break from sex work was associated with a loss of HIV-specific CD8+ responses. Late seroconversion may occur in HIV-1-resistant sex workers despite preceding HIV-specific CD8+ responses. Seroconversion generally occurs in the absence of detectable CTL escape mutations and may relate to the waning of HIV-specific CD8+ responses due to reduced antigenic exposure.

Appay V, Nixon DF, Donahoe SM, Gillespie GM, Dong T, King A, Ogg GS, Spiegel HM, Conlon C, Spina CA et al. 2000. HIV-specific CD8(+) T cells produce antiviral cytokines but are impaired in cytolytic function. J Exp Med, 192 (1), pp. 63-75. | Show Abstract | Read more

The use of peptide-human histocompatibility leukocyte antigen (HLA) class I tetrameric complexes to identify antigen-specific CD8(+) T cells has provided a major development in our understanding of their role in controlling viral infections. However, questions remain about the exact function of these cells, particularly in HIV infection. Virus-specific cytotoxic T lymphocytes exert much of their activity by secreting soluble factors such as cytokines and chemokines. We describe here a method that combines the use of tetramers and intracellular staining to examine the functional heterogeneity of antigen-specific CD8(+) T cells ex vivo. After stimulation by specific peptide antigen, secretion of interferon (IFN)-gamma, tumor necrosis factor (TNF)-alpha, macrophage inflammatory protein (MIP)-1beta, and perforin is analyzed by FACS((R)) within the tetramer-positive population in peripheral blood. Using this method, we have assessed the functional phenotype of HIV-specific CD8(+) T cells compared with cytomegalovirus (CMV)-specific CD8(+) T cells in HIV chronic infection. We show that the majority of circulating CD8(+) T cells specific for CMV and HIV antigens are functionally active with regards to the secretion of antiviral cytokines in response to antigen, although a subset of tetramer-staining cells was identified that secretes IFN-gamma and MIP-1beta but not TNF-alpha. However, a striking finding is that HIV-specific CD8(+) T cells express significantly lower levels of perforin than CMV-specific CD8(+) T cells. This lack of perforin is linked with persistent CD27 expression on HIV-specific cells, suggesting impaired maturation, and specific lysis ex vivo is lower for HIV-specific compared with CMV-specific cells from the same donor. Thus, HIV-specific CD8(+) T cells are impaired in cytolytic activity.

Cited:

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Scopus

John GC, Rousseau C, Dong T, Rowland-Jones S, Nduati R, Mbori-Ngacha D, Rostron T, Kreiss JK, Richardson BA, Overbaugh J. 2000. Maternal SDF1 3 ' A polymorphism is associated with increased perinatal human immunodeficiency virus type 1 transmission JOURNAL OF VIROLOGY, 74 (12), pp. 5736-5739. | Show Abstract | Read more

Genetic polymorphisms in chemokine and chemokine receptor genes influence susceptibility to human immunodeficiency virus type 1 (HIV-1) infection and disease progression, but little is known regarding the association between these allelic variations and the ability of the host to transmit virus. In this study, we show that the maternal heterozygous SDF1 genotype (SDF1 3'A/wt) is associated with perinatal transmission of HIV-1 (risk ratio [RR], 1.8; 95% confidence interval [CI] , 1.0 to 3.3) and particularly postnatal breastmilk transmission (RR, 3.1; 95% CI, 1.1 to 8.6). In contrast, the infant SDF1 genotype had no effect on mother-to-infant transmission. These data suggest that SDF1, which is a ligand for the T- tropic HIV-1 coreceptor CXCR4, may affect the ability of a mother to transmit the virus to her infant. This suggests that a genetic polymorphism in a gene encoding a chemokine receptor l igand may be associated with increased infectivity of the index case and highlights the importance of considering transmission as well as clinical outcome in designing chemokine-based therapies for HIV-1.

Kaul R, Plummer FA, Kimani J, Dong T, Kiama P, Rostron T, Njagi E, MacDonald KS, Bwayo JJ, McMichael AJ, Rowland-Jones SL. 2000. HIV-1-specific mucosal CD8+ lymphocyte responses in the cervix of HIV-1-resistant prostitutes in Nairobi. J Immunol, 164 (3), pp. 1602-1611. | Show Abstract

Understanding how individuals with a high degree of HIV exposure avoid persistent infection is paramount to HIV vaccine design. Evidence suggests that mucosal immunity, particularly virus-specific CTL, could be critically important in protection against sexually acquired HIV infection. Therefore, we have looked for the presence of HIV-specific CD8+ T cells in cervical mononuclear cells from a subgroup of highly HIV-exposed but persistently seronegative female sex workers in Nairobi. An enzyme-linked immunospot assay was used to measure IFN-gamma release in response to known class I HLA-restricted CTL epitope peptides using effector cells from the blood and cervix of HIV-1-resistant and -infected sex workers and from lower-risk uninfected controls. Eleven of 16 resistant sex workers had HIV-specific CD8+ T cells in the cervix, and a similar number had detectable responses in blood. Where both blood and cervical responses were detected in the same individual, the specificity of the responses was similar. Neither cervical nor blood responses were detected in lower-risk control donors. HIV-specific CD8+ T cell frequencies in the cervix of HIV-resistant sex workers were slightly higher than in blood, while in HIV-infected donor cervical response frequencies were markedly lower than blood, so that there was relative enrichment of cervical responses in HIV-resistant compared with HIV-infected donors. HIV-specific CD8+ T cell responses in the absence of detectable HIV infection in the genital mucosa of HIV-1-resistant sex workers may be playing an important part in protective immunity against heterosexual HIV-1 transmission.

Tan R, Xu X, Ogg GS, Hansasuta P, Dong T, Rostron T, Luzzi G, Conlon CP, Screaton GR, McMichael AJ, Rowland-Jones S. 1999. Rapid death of adoptively transferred T cells in acquired immunodeficiency syndrome. Blood, 93 (5), pp. 1506-1510. | Show Abstract

Human immunodeficiency virus (HIV)-specific cytotoxic T lymphocytes (CTL) probably play the major role in controlling HIV replication. However, the value of adoptive transfer of HIV-specific CTL expanded in vitro to HIV+ patients has been limited: this contrasts with the success of CTL therapy in treating or preventing Epstein-Barr virus and cytomegalovirus disease after bone marrow transplantation (BMT). We investigated the fate of expanded HIV-specific CTL clones in vivo following adoptive transfer to a patient with acquired immunodeficiency syndrome (AIDS). Two autologous CTL clones specific for HIV Gag and Pol were expanded to large numbers (>10(9)) in vitro and infused into an HIV-infected patient whose viral load was rising despite antiretroviral therapy. The fate of one clone was monitored by staining peripheral blood mononuclear cells (PBMCs) with T-cell receptor-specific tetrameric major histocompatibility complex (MHC)-peptide complexes. Although the CTL transfer was well tolerated, there were no significant changes in CD4 and CD8 lymphocyte counts and virus load. By tracking an infused clone using soluble MHC-peptide complexes, we show that cells bearing the Gag-specific T-cell receptors were rapidly eliminated within hours of infusion through apoptosis. Thus, the failure of adoptively transferred HIV-specific CTL to reduce virus load in AIDS may be due to rapid apoptosis of the infused cells, triggered by a number of potential mechanisms. Further trials of adoptive transfer of CTL should take into account the susceptibility of infused cells to in vivo apoptosis.

Dorrell L, Dong T, Ogg GS, Lister S, McAdam S, Rostron T, Conlon C, McMichael AJ, Rowland-Jones SL. 1999. Distinct recognition of non-clade B human immunodeficiency virus type 1 epitopes by cytotoxic T lymphocytes generated from donors infected in Africa. J Virol, 73 (2), pp. 1708-1714. | Show Abstract

We present detailed studies of human immunodeficiency virus (HIV)-specific cytotoxic T-lymphocyte (CTL) responses to clade A or C HIV type 1 in three donors infected in East Africa. We define several novel non-clade B CTL epitopes, including some restricted by HLA alleles common in Africans. Although cross-clade CTL recognition of these epitopes does occur, recognition can also be highly clade specific.

Rowland-Jones SL, Dong T, Fowke KR, Kimani J, Krausa P, Newell H, Blanchard T, Ariyoshi K, Oyugi J, Ngugi E et al. 1998. Cytotoxic T cell responses to multiple conserved HIV epitopes in HIV-resistant prostitutes in Nairobi. J Clin Invest, 102 (9), pp. 1758-1765. | Show Abstract | Read more

Many people who remain persistently seronegative despite frequent HIV exposure have HIV-specific immune responses. The study of these may provide information about mechanisms of natural protective immunity to HIV-1. We describe the specificity of cytotoxic T lymphocyte responses to HIV in seronegative prostitutes in Nairobi who are apparently resistant to HIV infection. These women have had frequent exposure to a range of African HIV-1 variants, primarily clades A, C, and D, for up to 12 yr without becoming infected. Nearly half of them have CTL directed towards epitopes previously defined for B clade virus, which are largely conserved in the A and D clade sequences. Stronger responses are frequently elicited using the A or D clade version of an epitope to stimulate CTL, suggesting that they were originally primed by exposure to these virus strains. CTL responses have been defined to novel epitopes presented by HLA class I molecules associated with resistance to infection in the cohort, HLA-A*6802 and HLA-B18. Estimates using a modified interferon-gamma Elispot assay indicate a circulating frequency of CTL to individual epitopes of between 1:3,200 and 1:50,000. Thus, HIV-specific immune responses-particularly cross-clade CTL activity- may be responsible for protection against persistent HIV infection in these African women.

Ogg GS, Dong T, Hansasuta P, Dorrell L, Clarke J, Coker R, Luzzi G, Conlon C, McMichael AP, Rowland-Jones S. 1998. Four novel cytotoxic T-lymphocyte epitopes in the highly conserved major homology region of HIV-1 Gag, restricted through B*4402, B*1801, A*2601, B*70 (B*1509) AIDS, 12 (12), pp. 1561-1563. | Read more

Rowland-Jones S, Colbert RA, Dong T, McAdam S, Brown M, Ariyoshi K, Sabally A, Whittle H, McMichael A. 1998. Distinct recognition of closely-related HIV-1 and HIV-2 cytotoxic T-cell epitopes presented by HLA-B*2703 and B*2705 AIDS, 12 (11), pp. 1391-1393. | Read more

Price DA, Sewell AK, Dong T, Tan R, Goulder PJ, Rowland-Jones SL, Phillips RE. 1998. Antigen-specific release of beta-chemokines by anti-HIV-1 cytotoxic T lymphocytes. Curr Biol, 8 (6), pp. 355-358. | Show Abstract | Read more

A major advance in understanding human immunodeficiency virus (HIV) biology was the discovery that the beta-chemokines MIP-1 alpha (macrophage inflammatory protein-1 alpha), MIP-1 beta (macrophage inflammatory protein-1 beta) and RANTES (regulated on activation, normal T-cell expressed and secreted) inhibit entry of HIV-1 into CD4+ cells by blocking the critical interaction between the CCR5 coreceptor and the V3 domain of the viral envelope glycoprotein gp120 [1,2]. CD8+ lymphocytes are a major source of beta-chemokines [3], but the stimulus for chemokine release has not been well defined. Here, we have shown that engagement of CD8+ cytotoxic T lymphocytes (CTLs) with HIV-1-encoded human leukocyte antigen (HLA) class I-restricted peptide antigens caused rapid and specific release of these beta-chemokines. This release paralleled cytolytic activity and could be attenuated by naturally occurring amino acid variation within the HLA class I-restricted peptide sequence. Epitope variants that bound to appropriate HLA class I molecules but failed to stimulate cytolytic activity in CTLs also failed to stimulate chemokine release. We conclude that signalling through the T-cell receptor (TCR) following binding of antigen results in beta-chemokine release from CTLs in addition to cytolytic activity, and that both responses can be abolished by epitope mutation. These results suggest that antigenic variation within HIV-1 might not only allow the host cell to escape lysis, but might also contribute to the propagation of infection by failing to activate beta-chemokine-mediated inhibition of HIV-1 entry.

Rowland-Jones S, Dong T, Krausa P, Sutton J, Newell H, Ariyoshi K, Gotch F, Sabally S, Corrah T, Kimani J et al. 1998. The role of cytotoxic T-cells in HIV infection. Dev Biol Stand, 92 pp. 209-214. | Show Abstract

HIV-specific cytotoxic T lymphocytes (CTL) are believed to play a major role in controlling virus levels through the asymptomatic period of HIV infection. For the rational design of an HIV vaccine, we need to know whether protective immunity can ever develop following HIV exposure in people who remain uninfected. We have detected HIV-specific CTL in 5/6 repeatedly exposed, persistently seronegative female sex-workers in The Gambia. Their CTL, repeatedly detected over two years, recognise epitopes presented by HLA-B35 which are cross-reactive between HIV-1 & HIV-2, suggesting they could have been primed first by HIV-2 exposure and subsequently boosted by exposure to HIV-1. Using previously identified clade B HIV-1 epitope peptides, we have now detected HIV-specific CTL in 6/15 highly exposed and apparently HIV-resistant Kenyan prostitutes, predominantly towards epitopes highly conserved between B and the Kenyan A & D clades of HIV-1. This CTL activity towards conserved virus epitopes may represent protective immunity to HIV generated in response to repeated exposure, and prophylactic HIV vaccines should aim to generate similar CTL responses.

Lalvani A, Dong T, Ogg G, Patham AA, Newell H, Hill AV, McMichael AJ, Rowland-Jones S. 1997. Optimization of a peptide-based protocol employing IL-7 for in vitro restimulation of human cytotoxic T lymphocyte precursors. J Immunol Methods, 210 (1), pp. 65-77. | Show Abstract | Read more

A variety of different methods for the in vitro restimulation of human cytotoxic T lymphocyte (CTL) precursors (CTLp) are in use. Our aim was to enhance the detection of circulating human CTLp in peripheral blood. We have developed a standardized and highly efficient method for restimulating CTLp. Synthetic peptides were used to restimulate cognate CTLp from peripheral blood mononuclear cells (PBMC), and effector CTL capable of lysing peptide-pulsed and virus infected targets were generated. The effects of several parameters on CTL specific for influenza A, EBV and HIV-1 were evaluated, and the optimum peptide concentration for CTL generation was established. Supplementation of initial cultures with IL-7 greatly enhanced peptide-specific lytic activity for all peptides tested and the dose-response relationship for IL-7 was delineated. A novel technique using peptide-MHC class I molecule tetramers to stain T cells bearing cognate T cell receptors permitted enumeration of antigen-specific CD8 + CTL during in vitro restimulation; IL-7 supplementation selectively expanded the population of peptide-specific CD8 + CTL. Importantly, this protocol, whilst enhancing the restimulation and lytic activity of secondary CTL, does not induce primary CTL in vitro. The improved efficiency with which CTL are generated in this system substantially enhances the sensitivity of CTL culture and the 51Cr release assay to detect low levels of CTL activity.

Xu XN, Screaton GR, Gotch FM, Dong T, Tan R, Almond N, Walker B, Stebbings R, Kent K, Nagata S et al. 1997. Evasion of cytotoxic T lymphocyte (CTL) responses by nef-dependent induction of Fas ligand (CD95L) expression on simian immunodeficiency virus-infected cells. J Exp Med, 186 (1), pp. 7-16. | Show Abstract | Read more

Inoculation of macaques with live attenuated SIV strains has been shown to protect against subsequent challenge with wild-type SIV. The protective mechanism(s) remain obscure. To study the effect in more detail, we have investigated the role of virus-specific CTL responses in macaques infected with an attenuated SIV strain (pC8), which has a four-amino acid deletion in the nef gene, as compared with the wild-type SIVmac32H clone (pJ5). Cynomolgus macaques infected with pC8 were protected against subsequent challenge with pJ5 and did not develop any AIDS-like symptoms in the 12 months after infection. The pC8-induced protection was associated with high levels of virus-specific CTL responses to a variety of viral antigens. In contrast, pJ5-infected macaques had little, if any, detectable CTL response to the viral proteins after three months. The latter group of macaques also showed increased Fas expression and apoptotic cell death in both the CD4(+) and CD8(+) populations. In vitro, pJ5 but not pC8 leads to an increase in FasL expression on infected cells. Thus the expression of FasL may protect infected cells from CTL attack, killing viral-specific CTLs in the process, and providing a route for escaping the immune response, leading to the increased pathogenicity of pJ5. pC8, on the other hand does not induce FasL expression, allowing the development of a protective CTL response. Furthermore, interruption of the Fas-FasL interaction allows the regeneration of viral-specific CTL responses in pJ5-infected animals. This observation suggests an additional therapeutic approach to the treatment of AIDS.

Dong T, Boyd D, Rosenberg W, Alp N, Takiguchi M, McMichael A, Rowland-Jones S. 1996. An HLA-B35-restricted epitope modified at an anchor residue results in an antagonist peptide. Eur J Immunol, 26 (2), pp. 335-339. | Show Abstract | Read more

Peptides associated with HLA-B35 commonly have a proline or occasionally a serine residue in the P2 anchor position of the peptide, with a tyrosine at the C terminus. Based on this motif, we identified an octamer epitope from influenza A matrix protein which is presented by HLA-B35. The requirements for MHC binding and T cell receptor contact have been analyzed using analogs of this peptide with substitutions at positions 1, 2, 4, 7 and 8. The natural epitope contains a serine residue at P2 of the peptide. Substitution of this residue with proline (the favored amino acid in this position in B35-associated peptides) considerably enhances binding to HLA-B35 in the T2-B35 cell line, but the peptide is not recognized by the majority of CTL clones and can antagonize recognition of the index peptide. This suggests that a conservative substitution at the P2 anchor position results in a conformational change in the peptide-MHC surface exposed to the T cell receptor.

ROWLANDJONES S, SUTTON J, ARIYOSHI K, DONG T, GOTCH F, MACADAM S, SABALLY S, WHITBY D, GALLIMORE A, SCHULTZ T et al. 1995. HIV-SPECIFIC CYTOTOXIC T-CELLS IN HIGHLY EXPOSED BUT UNINFECTED GAMBIAN WOMEN JOURNAL OF CELLULAR BIOCHEMISTRY, pp. 154-154.

Rowland-Jones S, Sutton J, Ariyoshi K, Dong T, Gotch F, McAdam S, Whitby D, Sabally S, Gallimore A, Corrah T. 1995. HIV-specific cytotoxic T-cells in HIV-exposed but uninfected Gambian women. Nat Med, 1 (1), pp. 59-64. | Show Abstract | Read more

A crucial requirement in the rational design of a prophylactic vaccine against the human immunodeficiency virus (HIV) is to establish whether or not protective immunity can occur following natural infection. The immune response to HIV infection is characterized by very vigorous HIV-specific cytotoxic T-lymphocyte (CTL) activity. We have identified four HIV-1 and HIV-2 cross-reactive peptide epitopes, presented to CTL from HIV-infected Gambians by HLA-B35 (the most common Gambian class I HLA molecule). These peptides were used to elicit HIV-specific CTLs from three out of six repeatedly exposed but HIV-seronegative female prostitutes with HLA-B35. These women remain seronegative with no evidence of HIV infection by polymerase chain reaction or viral culture. Their CTL activity may represent protective immunity against HIV infection.

Cole SL, Dunning J, Kok WL, Benam KH, Benlahrech A, Repapi E, Martinez FO, Drumright L, Powell TJ, Bennett M et al. 2017. M1-like monocytes are a major immunological determinant of severity in previously healthy adults with life-threatening influenza. JCI Insight, 2 (7), pp. e91868. | Show Abstract | Read more

In each influenza season, a distinct group of young, otherwise healthy individuals with no risk factors succumbs to life-threatening infection. To better understand the cause for this, we analyzed a broad range of immune responses in blood from a unique cohort of patients, comprising previously healthy individuals hospitalized with and without respiratory failure during one influenza season, and infected with one specific influenza A strain. This analysis was compared with similarly hospitalized influenza patients with known risk factors (total of n = 60 patients recruited). We found a sustained increase in a specific subset of proinflammatory monocytes, with high TNF-α expression and an M1-like phenotype (independent of viral titers), in these previously healthy patients with severe disease. The relationship between M1-like monocytes and immunopathology was strengthened using murine models of influenza, in which severe infection generated using different models (including the high-pathogenicity H5N1 strain) was also accompanied by high levels of circulating M1-like monocytes. Additionally, a raised M1/M2 macrophage ratio in the lungs was observed. These studies identify a specific subtype of monocytes as a modifiable immunological determinant of disease severity in this subgroup of severely ill, previously healthy patients, offering potential novel therapeutic avenues.

Nakaya HI, Clutterbuck E, Kazmin D, Wang L, Cortese M, Bosinger SE, Patel NB, Zak DE, Aderem A, Dong T et al. 2016. Systems biology of immunity to MF59-adjuvanted versus nonadjuvanted trivalent seasonal influenza vaccines in early childhood. Proc Natl Acad Sci U S A, 113 (7), pp. 1853-1858. | Show Abstract | Read more

The dynamics and molecular mechanisms underlying vaccine immunity in early childhood remain poorly understood. Here we applied systems approaches to investigate the innate and adaptive responses to trivalent inactivated influenza vaccine (TIV) and MF59-adjuvanted TIV (ATIV) in 90 14- to 24-mo-old healthy children. MF59 enhanced the magnitude and kinetics of serum antibody titers following vaccination, and induced a greater frequency of vaccine specific, multicytokine-producing CD4(+) T cells. Compared with transcriptional responses to TIV vaccination previously reported in adults, responses to TIV in infants were markedly attenuated, limited to genes regulating antiviral and antigen presentation pathways, and observed only in a subset of vaccinees. In contrast, transcriptional responses to ATIV boost were more homogenous and robust. Interestingly, a day 1 gene signature characteristic of the innate response (antiviral IFN genes, dendritic cell, and monocyte responses) correlated with hemagglutination at day 28. These findings demonstrate that MF59 enhances the magnitude, kinetics, and consistency of the innate and adaptive response to vaccination with the seasonal influenza vaccine during early childhood, and identify potential molecular correlates of antibody responses.

Zhang Y-H, Zhao Y, Rajapaksa US, Lawrence TM, Peng Y-C, Liu J, Xu K, Hu K, Qin L, Liu N et al. 2016. A Comprehensive Analysis of the Impact of HIV on HCV Immune Responses and Its Association with Liver Disease Progression in a Unique Plasma Donor Cohort. PLoS One, 11 (7), pp. e0158037. | Show Abstract | Read more

OBJECTIVE: Human Immunodeficiency Virus (HIV) and Hepatitis C virus (HCV) co-infection is recognized as a major cause of morbidity and mortality among HIV-1 infected patients. Our understanding of the impact of HIV infection on HCV specific immune responses and liver disease outcome is limited by the heterogeneous study populations with genetically diverse infecting viruses, varying duration of infection and anti-viral treatment. METHODS: Viral-specific immune responses in a cohort of 151 HCV mono- and HIV co-infected former plasma donors infected with a narrow source of virus were studied. HCV and HIV specific T cell responses were correlated with clinical data. RESULTS: HIV-1 accelerated liver disease progression and decreased HCV specific T cell immunity. The magnitude of HCV specific T cell responses inversely correlated with lower HCV RNA load and reduced liver injury as assessed by non-invasive markers of liver fibrosis. HIV co-infection reduced the frequency of HCV specific CD4+ T cells with no detectable effect on CD8+ T cells or neutralizing antibody levels. CONCLUSION: Our study highlights the impact of HIV co-infection on HCV specific CD4+ T cell responses in a unique cohort of patients for both HCV and HIV and suggests a crucial role for these cells in controlling chronic HCV replication and liver disease progression.

Dong T. 2015. CD8+ cytotoxic T lymphocytes in human influenza virus infection. Natl Sci Rev, 2 (3), pp. 264-265. | Read more

Bridgeman A, Maelfait J, Davenne T, Partridge T, Peng Y, Mayer A, Dong T, Kaever V, Borrow P, Rehwinkel J. 2015. Viruses transfer the antiviral second messenger cGAMP between cells. Science, 349 (6253), pp. 1228-1232. | Show Abstract | Read more

Cyclic GMP-AMP synthase (cGAS) detects cytosolic DNA during virus infection and induces an antiviral state. cGAS signals by synthesis of a second messenger, cyclic GMP-AMP (cGAMP), which activates stimulator of interferon genes (STING). We show that cGAMP is incorporated into viral particles, including lentivirus and herpesvirus virions, when these are produced in cGAS-expressing cells. Virions transferred cGAMP to newly infected cells and triggered a STING-dependent antiviral program. These effects were independent of exosomes and viral nucleic acids. Our results reveal a way by which a signal for innate immunity is transferred between cells, potentially accelerating and broadening antiviral responses. Moreover, infection of dendritic cells with cGAMP-loaded lentiviruses enhanced their activation. Loading viral vectors with cGAMP therefore holds promise for vaccine development.

Zhang Y, Makvandi-Nejad S, Qin L, Zhao Y, Zhang T, Wang L, Repapi E, Taylor S, McMichael A, Li N et al. 2015. Interferon-induced transmembrane protein-3 rs12252-C is associated with rapid progression of acute HIV-1 infection in Chinese MSM cohort. AIDS, 29 (8), pp. 889-894. | Show Abstract | Read more

BACKGROUND: The interferon-inducible transmembrane protein-3 (IFITM3) is a protein that restricts multiple pathogenic viruses such as influenza virus. The single-nucleotide polymorphism rs12252-C, which is rare in Caucasian populations, but much more common in the Han Chinese population, has been found in much higher homozygous frequency in patients with severe acute influenza. Until now, there has been no study on the effect of this genetic variant on the clinical control of other viral infections. OBJECTIVES: To investigate the impact of IFITM3-rs12252 genotypes on primary HIV-1 infection progression in an acute HIV-1-infected cohort in Beijing (PRIMO), China. DESIGN AND METHODS: We identified IFITM3-rs12252 genotypes of 178 acute HIV-1-infected patients and 196 HIV-negative candidates from the PRIMO cohort. HIV-1 viral load and CD4(+) T-cell counts were monitored at multiple time points during the first year of infection, and the association between IFITM3-rs12252 genotype and disease progression was evaluated. RESULTS: The current study shows that the IFITM3-rs12252 genetic variant affects the progression of HIV-1 infection, but not the acquisition. A significantly higher frequency of the CC/CT genotypes was found in rapid progressors compared to nonprogressors. Patients with CC/CT genotypes showed an elevated peak viremia level and significantly lower CD4(+) T-cell count at multiple time points during the first year of primary infection, and a significantly higher risk of rapid decline of the CD4(+) T-cell count to below 350  cells/μl. CONCLUSION: A novel association between IFITM3 gene polymorphism and rapid disease progression is reported in an acute HIV-1-infected MSM cohort in China.

Peng Y, Wang B, Talaat K, Karron R, Powell TJ, Zeng H, Dong D, Luke CJ, McMichael A, Subbarao K, Dong T. 2015. Boosted Influenza-Specific T Cell Responses after H5N1 Pandemic Live Attenuated Influenza Virus Vaccination. Front Immunol, 6 (JUN), pp. 287. | Show Abstract | Read more

BACKGROUND: In a phase I clinical trial, a H5N1 pandemic live attenuated influenza virus (pLAIV) VN2004 vaccine bearing avian influenza H5N1 hemagglutinin (HA) and NA genes on the A/Ann Arbor cold-adapted vaccine backbone displayed very restricted replication. We evaluated T cell responses to H5N1 pLAIV vaccination and assessed pre-existing T cell responses to determine whether they were associated with restricted replication of the H5N1 pLAIV. METHOD: ELISPOT assays were performed using pools of overlapping peptides spanning the entire H5N1 proteome and the HA proteins of relevant seasonal H1N1 and H3N2 viruses. We tested stored peripheral blood mononuclear cells (PBMCs) from 21 study subjects who received two doses of the H5N1 pLAIV. The PBMCs were collected 1 day before and 7 days after the first and second pLAIV vaccine doses, respectively. RESULT: T cell responses to conserved internal proteins M and NP were significantly boosted by vaccination (p = 0.036). In addition, H5N1 pLAIV appeared to preferentially stimulate and boost pre-existing seasonal influenza virus HA-specific T cell responses that showed low cross-reactivity with the H5 HA. We confirmed this observation by T cell cloning and identified a novel HA-specific epitope. However, we did not find any evidence that pre-existing T cells prevented pLAIV replication and take. CONCLUSION: We found that cross-reactive T cell responses could be boosted by pLAIV regardless of the induction of antibody. The impact of the "original antigenic sin" phenomenon in a subset of volunteers, with preferential expansion of seasonal influenza-specific but not H5N1-specific T cell responses merits further investigation.

Zhang Y-H, Zhao Y, Li N, Peng Y-C, Giannoulatou E, Jin R-H, Yan H-P, Wu H, Liu J-H, Liu N et al. 2013. Interferon-induced transmembrane protein-3 genetic variant rs12252-C is associated with severe influenza in Chinese individuals. Nat Commun, 4 pp. 1418. | Show Abstract | Read more

The SNP rs12252-C allele alters the function of interferon-induced transmembrane protein-3 increasing the disease severity of influenza virus infection in Caucasians, but the allele is rare. However, rs12252-C is much more common in Han Chinese. Here we report that the CC genotype is found in 69% of Chinese patients with severe pandemic influenza A H1N1/09 virus infection compared with 25% in those with mild infection. Specifically, the CC genotype was estimated to confer a sixfold greater risk for severe infection than the CT and TT genotypes. More importantly, because the risk genotype occurs with such a high frequency, its effect translates to a large population-attributable risk of 54.3% for severe infection in the Chinese population studied compared with 5.4% in Northern Europeans. Interferon-induced transmembrane protein-3 genetic variants could, therefore, have a strong effect of the epidemiology of influenza in China and in people of Chinese descent.

Zhao Y, Zhang Y-H, Denney L, Young D, Powell TJ, Peng Y-C, Li N, Yan H-P, Wang D-Y, Shu Y-L et al. 2012. High levels of virus-specific CD4+ T cells predict severe pandemic influenza A virus infection. Am J Respir Crit Care Med, 186 (12), pp. 1292-1297. | Show Abstract | Read more

RATIONALE: T-cell responses have been implicated in control and exacerbation of lung injury during influenza A virus (IAV) infection. OBJECTIVES: To examine the breadth and magnitude of influenza-specific CD4(+) and CD8(+) T-cell responses during acute phase of infection. METHODS: Influenza-specific T-cell response to the entire pandemic H1N1/09 IAV proteome and T cell-related cytokine levels were measured in blood from previously healthy individuals with mild (n = 32) and severe (n = 16) IAV infection during the 2009 influenza pandemic. Virus-specific T-cell response in lung and blood was also performed in two acutely infected, severely ill patients using fluorescent-conjugated pdmH1N1/09 Matrix-MHC-I tetrameric complexes. MEASUREMENTS AND MAIN RESULTS: Strong and broad CD4(+) but not CD8(+) T-cell responses were observed in the blood, and were higher in those with severe disease. Antigen-specific CD8(+) T cells in the lungs were on average 45-fold higher compared with blood in severely ill patients. Paradoxically, in patients with severe disease, IL-17, IL-2, IL-4, and IFN-γ levels were significantly decreased. CONCLUSIONS: High levels of circulating virus-specific CD4(+) T cells to two viral internal proteins (nucleoprotein and matrix) in the first phase of infection are associated with subsequent development of severe IAV infection. This finding could be an early and specific marker for ensuing clinical deterioration. Contrasting levels of antigen-specific CD8(+) T cells in lungs and blood have implications on design and analysis of clinical trials for T-cell vaccines because measurements of T cells in the periphery may not reflect events in the lungs.

Rajapaksa US, Li D, Peng Y-C, McMichael AJ, Dong T, Xu X-N. 2012. HLA-B may be more protective against HIV-1 than HLA-A because it resists negative regulatory factor (Nef) mediated down-regulation. Proc Natl Acad Sci U S A, 109 (33), pp. 13353-13358. | Show Abstract | Read more

Human leukocyte antigen HLA-B alleles have better protective activity against HIV-1 than HLA-A alleles, possibly due to differences in HLA-restricted HIV-1-specific CD8+ cytotoxic T lymphocyte (CTL) function, but the mechanism is unknown. HIV-1 negative regulatory factor (Nef) mediates down-regulation of surface expression of class I HLA (HLA-I) and may therefore impair immune recognition by CTL. Because of sequence differences in the cytoplasmic domains, HLA-A and -B are down-regulated by Nef but HLA-C and -E are not affected. However, the latter are expressed at low levels and are not of major importance in the CTL responses to HIV-1. Here, we compared the role of the cytoplasmic domains of HLA-A and -B in Nef-mediated escape from CTL. We found HLA-B cytoplasmic domains were more resistant to Nef-mediated down-regulation than HLA-A cytoplasmic domains and demonstrated that these differences affect CTL recognition of virus-infected cells in vitro. We propose that the relative resistance to Nef-mediated down-regulation by the cytoplasmic domains of HLA-B compared with HLA-A contributes to the better control of HIV-1 infection associated with HLA-B-restricted CTLs.

Wilkinson TM, Li CKF, Chui CSC, Huang AKY, Perkins M, Liebner JC, Lambkin-Williams R, Gilbert A, Oxford J, Nicholas B et al. 2012. Preexisting influenza-specific CD4+ T cells correlate with disease protection against influenza challenge in humans. Nat Med, 18 (2), pp. 274-280. | Show Abstract | Read more

Protective immunity against influenza virus infection is mediated by neutralizing antibodies, but the precise role of T cells in human influenza immunity is uncertain. We conducted influenza infection studies in healthy volunteers with no detectable antibodies to the challenge viruses H3N2 or H1N1. We mapped T cell responses to influenza before and during infection. We found a large increase in influenza-specific T cell responses by day 7, when virus was completely cleared from nasal samples and serum antibodies were still undetectable. Preexisting CD4+, but not CD8+, T cells responding to influenza internal proteins were associated with lower virus shedding and less severe illness. These CD4+ cells also responded to pandemic H1N1 (A/CA/07/2009) peptides and showed evidence of cytotoxic activity. These cells are an important statistical correlate of homotypic and heterotypic response and may limit severity of influenza infection by new strains in the absence of specific antibody responses. Our results provide information that may aid the design of future vaccines against emerging influenza strains.

Ranasinghe SRF, Kramer HB, Wright C, Kessler BM, di Gleria K, Zhang Y, Gillespie GM, Blais M-E, Culshaw A, Pichulik T et al. 2011. The Antiviral Efficacy of HIV-Specific CD8(+) T-Cells to a Conserved Epitope Is Heavily Dependent on the Infecting HIV-1 Isolate PLOS PATHOGENS, 7 (5), | Show Abstract | Read more

A major challenge to developing a successful HIV vaccine is the vast diversity of viral sequences, yet it is generally assumed that an epitope conserved between different strains will be recognised by responding T-cells. We examined whether an invariant HLA-B8 restricted Nef 90-97 epitope FL8 shared between five high titre viruses and eight recombinant vaccinia viruses expressing Nef from different viral isolates (clades A-H) could activate antiviral activity in FL8-specific cytotoxic T-lymphocytes (CTL). Surprisingly, despite epitope conservation, we found that CTL antiviral efficacy is dependent on the infecting viral isolate. Only 23% of Nef proteins, expressed by HIV-1 isolates or as recombinant vaccinia-Nef, were optimally recognised by CTL. Recognition of the HIV-1 isolates by CTL was independent of clade-grouping but correlated with virus-specific polymorphisms in the epitope flanking region, which altered immunoproteasomal cleavage resulting in enhanced or impaired epitope generation. The finding that the majority of virus isolates failed to present this conserved epitope highlights the importance of viral variance in CTL epitope flanking regions on the efficiency of antigen processing, which has been considerably underestimated previously. This has important implications for future vaccine design strategies since efficient presentation of conserved viral epitopes is necessary to promote enhanced anti-viral immune responses. © 2011 Ranasinghe et al.

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