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Sumaria N, Martin S, Pennington DJ. Constrained TCRγδ-associated Syk activity engages PI3K to facilitate thymic development of IL-17A-secreting γδ T cells. Sci Signal 2021; 14:14/692/eabc5884. [PMID: 34285131 DOI: 10.1126/scisignal.abc5884] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Murine γδ17 cells, which are T cells that bear the γδ T cell receptor (TCRγδ) and secrete interleukin-17A (IL-17A), are generated in the thymus and are critical for various immune responses. Although strong TCRγδ signals are required for the development of interferon-γ (IFN-γ)-secreting γδ cells (γδIFN cells), the generation of γδ17 cells requires weaker TCRγδ signaling. Here, we demonstrated that constrained activation of the kinase Syk downstream of TCRγδ was required for the thymic development of γδ17 cells. Increasing or decreasing Syk activity by stimulating TCRγδ or inhibiting Syk, respectively, substantially reduced γδ17 cell numbers. This delimited Syk activity optimally engaged the phosphoinositide 3-kinase (PI3K)-Akt signaling pathway, which maintained the expression of master regulators of the IL-17 program, RORγt and c-Maf. Inhibition of PI3K not only abrogated γδ17 cell development but also augmented the development of a distinct, previously undescribed subset of γδ T cells. These CD8+Ly6a+ γδ T cells had a type-I IFN gene expression signature and expanded in response to stimulation with IFN-β. Collectively, these studies elucidate how weaker TCRγδ signaling engages distinct signaling pathways to specify the γδ17 cell fate and identifies a role for type-I IFNs in γδ T cell development.
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Affiliation(s)
- Nital Sumaria
- Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, 4 Newark Street, London E1 2AT, UK
| | - Stefania Martin
- Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, 4 Newark Street, London E1 2AT, UK
| | - Daniel J Pennington
- Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, 4 Newark Street, London E1 2AT, UK.
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Tanko RF, Soares AP, Masson L, Garrett NJ, Samsunder N, Abdool Karim Q, Abdool Karim SS, Riou C, Burgers WA. Residual T cell activation and skewed CD8+ T cell memory differentiation despite antiretroviral therapy-induced HIV suppression. Clin Immunol 2018; 195:127-138. [PMID: 29883708 DOI: 10.1016/j.clim.2018.06.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Revised: 05/29/2018] [Accepted: 06/04/2018] [Indexed: 11/29/2022]
Abstract
HIV infection results in excessive T cell activation and dysfunction which may persist even during effective antiretroviral therapy (ART). The dynamics of immune 'deactivation' and extent to which T cell memory subsets normalize after ART are unclear. We longitudinally assessed the influence of 1 year of ART on the phenotype of T cells in HIV-infected African women, relative to matched HIV-uninfected women, using activation (CD38, HLA-DR) and differentiation markers (CD27, CD45RO). ART induced a substantial reduction in T cell activation, but remained higher than HIV-uninfected controls. ART largely normalized the distribution of CD4+ T cell memory subsets, while the distribution of CD8+ T cell memory subsets remained significantly skewed compared to HIV-uninfected individuals. Thus, there was a considerable but only partial reversal of T cell defects upon ART. Understanding T cell impairment may provide important insights into mechanisms of HIV pathogenesis in the era of ART.
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Affiliation(s)
- Ramla F Tanko
- Institute of Infectious Disease and Molecular Medicine and Department of Pathology, Division of Medical Virology, Faculty of Health Sciences, University of Cape Town, South Africa
| | - Andreia P Soares
- Institute of Infectious Disease and Molecular Medicine and Department of Pathology, Division of Medical Virology, Faculty of Health Sciences, University of Cape Town, South Africa
| | - Lindi Masson
- Institute of Infectious Disease and Molecular Medicine and Department of Pathology, Division of Medical Virology, Faculty of Health Sciences, University of Cape Town, South Africa; Centre for the AIDS Program of Research in South Africa (CAPRISA), University of KwaZulu-Natal, Durban, South Africa
| | - Nigel J Garrett
- Centre for the AIDS Program of Research in South Africa (CAPRISA), University of KwaZulu-Natal, Durban, South Africa
| | - Natasha Samsunder
- Centre for the AIDS Program of Research in South Africa (CAPRISA), University of KwaZulu-Natal, Durban, South Africa
| | - Quarraisha Abdool Karim
- Centre for the AIDS Program of Research in South Africa (CAPRISA), University of KwaZulu-Natal, Durban, South Africa; Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, NY, United States
| | - Salim S Abdool Karim
- Centre for the AIDS Program of Research in South Africa (CAPRISA), University of KwaZulu-Natal, Durban, South Africa; Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, NY, United States
| | - Catherine Riou
- Institute of Infectious Disease and Molecular Medicine and Department of Pathology, Division of Medical Virology, Faculty of Health Sciences, University of Cape Town, South Africa
| | - Wendy A Burgers
- Institute of Infectious Disease and Molecular Medicine and Department of Pathology, Division of Medical Virology, Faculty of Health Sciences, University of Cape Town, South Africa.
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Murday AS, Chaudhry S, Pauza CD. Interleukin-18 activates Vγ9Vδ2 + T cells from HIV-positive individuals: recovering the response to phosphoantigen. Immunology 2017; 151:385-394. [PMID: 28342224 DOI: 10.1111/imm.12735] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Revised: 01/23/2017] [Accepted: 02/23/2017] [Indexed: 12/12/2022] Open
Abstract
The study aimed to identify an immunoregulatory factor that restores the phosphoantigen response of Vγ9Vδ2+ T cells from HIV-positive individuals on antiretroviral therapy. It was designed to characterize the effects of interleukin-18 (IL-18) on proliferation and effector function in Vγ9Vδ2 T cells from HIV-negative individuals and test whether exogenous IL-18 reconstitutes the Vγ9Vδ2 T-cell response to phosphoantigen from HIV-positive donors. Vγ9Vδ2 T cells from HIV-negative individuals responded strongly to phosphoantigen or aminobisphosphonate stimulation of peripheral blood mononuclear cells (PBMC), whereas cells with similar T-cell receptor profiles from HIV-positive individuals only responded to aminobisphosphonate. Interleukin-18 was higher after aminobisphosphonate stimulation due to activation of the inflammasome pathway. Both IL-18 and IL-18 receptor levels were measured and the activity of exogenous IL-18 on HIV-negative and HIV-positive PBMC was evaluated in terms of Vγ9Vδ2 T-cell proliferation, memory subsets, cytokine expression and CD107a expression. Interleukin-18 stimulation increased proliferation, enhanced the accumulation of effector memory cells, and increased expression of cytotoxic markers in HIV-negative controls. When Vγ9Vδ2 T cells from HIV-positive individuals were stimulated with isopentenyl pyrophosphate in the presence of IL-18, there was increased proliferation, accumulation of memory cells, and higher expression of CD56, NKG2D and CD107a (markers of cytotoxic effector phenotype). Interleukin-18 stimulation specifically expanded the Vγ9-JγP+ subset of Vγ9Vδ2 T cells, as was expected for normal responses to phosphoantigen. Interleukin-18 is a potent stimulator of Vγ9Vδ2 T-cell proliferation and effector function. Therapies directed at reconstituting Vγ9Vδ2 T-cell activity in HIV-positive individuals should include stimulators of IL-18 or direct cytokine supplementation.
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Affiliation(s)
- Alanna S Murday
- Institute of Human Virology and Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Suchita Chaudhry
- Institute of Human Virology and Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
| | - C David Pauza
- Institute of Human Virology and Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
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Heterogeneous yet stable Vδ2(+) T-cell profiles define distinct cytotoxic effector potentials in healthy human individuals. Proc Natl Acad Sci U S A 2016; 113:14378-14383. [PMID: 27911793 DOI: 10.1073/pnas.1611098113] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Human γδ T cells display potent responses to pathogens and malignancies. Of particular interest are those expressing a γδ T-cell receptor (TCR) incorporating TCRδ-chain variable-region-2 [Vδ2(+)], which are activated by pathogen-derived phosphoantigens (pAgs), or host-derived pAgs that accumulate in transformed cells or in cells exposed to aminobisphosphonates. Once activated, Vδ2(+) T cells exhibit multiple effector functions that have made them attractive candidates for immunotherapy. Despite this, clinical trials have reported mixed patient responses, highlighting a need for better understanding of Vδ2(+) T-cell biology. Here, we reveal previously unappreciated functional heterogeneity between the Vδ2(+) T-cell compartments of 63 healthy individuals. In this cohort, we identify distinct "Vδ2 profiles" that are stable over time; that do not correlate with age, gender, or history of phosphoantigen activation; and that develop after leaving the thymus. Multiple analyses suggest these Vδ2 profiles consist of variable proportions of two dominant but contrasting Vδ2(+) T-cell subsets that have divergent transcriptional programs and that display mechanistically distinct cytotoxic potentials. Importantly, an individual's Vδ2 profile predicts defined effector capacities, demonstrated by contrasting mechanisms and efficiencies of killing of a range of tumor cell lines. In short, these data support patient stratification to identify individuals with Vδ2 profiles that have effector mechanisms compatible with tumor killing and suggest that tailored Vδ2-profile-specific activation protocols may maximize the chances of future treatment success.
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Tuero I, Venzon D, Robert-Guroff M. Mucosal and Systemic γδ+ T Cells Associated with Control of Simian Immunodeficiency Virus Infection. THE JOURNAL OF IMMUNOLOGY 2016; 197:4686-4695. [PMID: 27815422 DOI: 10.4049/jimmunol.1600579] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Accepted: 10/11/2016] [Indexed: 12/20/2022]
Abstract
γδ T cells act as a first line of defense against invading pathogens. However, despite their abundance in mucosal tissue, little information is available about their functionality in this compartment in the context of HIV/SIV infection. In this study, we evaluated the frequency, phenotype, and functionality of Vδ1 and Vδ2 T cells from blood, rectum, and the female reproductive tract (FRT) of rhesus macaques to determine whether these cells contribute to control of SIV infection. No alteration in the peripheral Vδ1/Vδ2 ratio in SIV-infected macaques was observed. However, CD8+ and CD4+CD8+ Vδ1 T cells were expanded along with upregulation of NKG2D, CD107, and granzyme B, suggesting cytotoxic function. In contrast, Vδ2 T cells showed a reduced ability to produce the inflammatory cytokine IFN-γ. In the FRT of SIV+ macaques, Vδ1 and Vδ2 showed comparable levels across vaginal, ectocervical, and endocervical tissues; however, endocervical Vδ2 T cells showed higher inflammatory profiles than the two other regions. No sex difference was seen in the rectal Vδ1/Vδ2 ratio. Several peripheral Vδ1 and/or Vδ2 T cell subpopulations expressing IFN-γ and/or NKG2D were positively correlated with decreased plasma viremia. Notably, Vδ2 CD8+ T cells of the endocervix were negatively correlated with chronic viremia. Overall, our results suggest that a robust Vδ1 and Vδ2 T cell response in blood and the FRT of SIV-infected macaques contribute to control of viremia.
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Affiliation(s)
- Iskra Tuero
- Immune Biology of Retroviral Infection Section, Vaccine Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892; and
| | - David Venzon
- Biostatistics and Data Management Section, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892
| | - Marjorie Robert-Guroff
- Immune Biology of Retroviral Infection Section, Vaccine Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892; and
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Cairo C, Surendran N, Harris KM, Mazan-Mamczarz K, Sakoda Y, Diaz-Mendez F, Tamada K, Gartenhaus RB, Mann DL, Pauza CD. Vγ2Vδ2 T cell Costimulation Increases NK cell Killing of Monocyte-derived Dendritic Cells. Immunology 2014; 144:422-430. [PMID: 25227493 PMCID: PMC4557679 DOI: 10.1111/imm.12386] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Revised: 09/09/2014] [Accepted: 09/12/2014] [Indexed: 12/24/2022] Open
Abstract
Interactions between NK and dendritic cells (DC) affect maturation and function of both cell populations, including NK killing of DC (editing) that is important for controlling the quality of immune responses. We also know that antigen-stimulated Vγ2Vδ2 T cells costimulate NK cells via 4-1BB to enhance killing of tumor cell lines but we do not know what regulates 4-1BB expression or whether other NK effector functions including DC killing, might also be influenced by NK:γδ T cell cross talk. Here we show that antigen-stimulated γδ T cells costimulate NK through ICOS:ICOSL and this signal increases NK killing of autologous DC. Effects of NK:γδ T cell co-culture, which could be reproduced with soluble ICOS-Fc fusion protein, included increased CD69 and 4-1BB expression, IFN-γ, TNF-α, MIP-1β, I-309, RANTES and sFasL production, as well as elevated mRNA levels for costimulatory receptors OX40 (TNFRSF4) and GITR (TNFRSF18). Thus, ICOS/ICOSL costimulation of NK by Vγ2Vδ2 T cells had broad effects on NK phenotype and effector functions. The NK γδ T cell cross talk links innate and antigen-specific lymphocyte responses in the control of cytotoxic effector function and dendritic cell killing. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Cristiana Cairo
- Institute of Human Virology, University of Maryland School of MedicineBaltimore, MD, USA
| | - Naveen Surendran
- Institute of Human Virology, University of Maryland School of MedicineBaltimore, MD, USA
| | - Kristina M Harris
- Department of Pathology, University of Maryland School of MedicineBaltimore, MD, USA
| | - Krystyna Mazan-Mamczarz
- School of Medicine Oncology Program, University of Maryland Marlene and Stewart Greenebaum Cancer Center, University of Maryland School of MedicineBaltimore, MD, USA
| | - Yukimi Sakoda
- Department of Otorhinolaryngology- Head and Neck Surgery, University of Maryland School of MedicineBaltimore, MD, USA
| | - Felisa Diaz-Mendez
- Institute of Human Virology, University of Maryland School of MedicineBaltimore, MD, USA
| | - Koji Tamada
- Department of Otorhinolaryngology- Head and Neck Surgery, University of Maryland School of MedicineBaltimore, MD, USA
| | - Ronald B Gartenhaus
- School of Medicine Oncology Program, University of Maryland Marlene and Stewart Greenebaum Cancer Center, University of Maryland School of MedicineBaltimore, MD, USA
| | - Dean L Mann
- Department of Pathology, University of Maryland School of MedicineBaltimore, MD, USA
| | - C David Pauza
- Institute of Human Virology, University of Maryland School of MedicineBaltimore, MD, USA
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Wu YL, Ding YP, Tanaka Y, Shen LW, Wei CH, Minato N, Zhang W. γδ T cells and their potential for immunotherapy. Int J Biol Sci 2014; 10:119-35. [PMID: 24520210 PMCID: PMC3920167 DOI: 10.7150/ijbs.7823] [Citation(s) in RCA: 105] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Accepted: 12/17/2013] [Indexed: 12/19/2022] Open
Abstract
Vγ9Vδ2 (also termed Vγ2Vδ2) T cells, a major human peripheral blood γδ T cell subset, recognize microbial (E)-4-hydroxy-3-methylbut-2-enyl diphosphate and endogenous isopentenyl diphosphate in a TCR-dependent manner. The recognition does not require specific accessory cells, antigen uptake, antigen processing, or MHC class I, class II, or class Ib expression. This subset of T cells plays important roles in mediating innate immunity against a wide variety of infections and displays potent and broad cytotoxic activity against human tumor cells. Because γδT cells express both natural killer receptors such as NKG2D and γδ T cell receptors, they are considered to represent a link between innate and adaptive immunity. In addition, activated γδ T cells express a high level of antigen-presenting cell-related molecules and can present peptide antigens derived from destructed cells to αβ T cells. Utilizing these antimicrobial and anti-tumor properties of γδ T cells, preclinical and clinical trials have been conducted to develop novel immunotherapies for infections and malignancies. Here, we review the immunological properties of γδ T cells including the underlying recognition mechanism of nonpeptitde antigens and summarize the results of γδ T cell-based therapies so far performed. Based on the results of the reported trials, γδ T cells appear to be a promising tool for novel immunotherapies against certain types of diseases.
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Affiliation(s)
- Yan-Ling Wu
- 1. Lab of Molecular Immunology, Zhejiang Provincial Center for Disease Control and Prevention, 630 Xincheng Road, Hangzhou, 310051, China
| | - Yan-Ping Ding
- 1. Lab of Molecular Immunology, Zhejiang Provincial Center for Disease Control and Prevention, 630 Xincheng Road, Hangzhou, 310051, China
- 2. Lab of Chemical Biology and Molecular Drug Design, College of Pharmaceutical Science, Zhejiang University of Technology, 18 Chaowang Road, Hangzhou, 310014, China
| | - Yoshimasa Tanaka
- 3. Center for Innovation in Immunoregulative Technology and Therapeutics, Graduate School of Medicine, Kyoto University, Kyoto, 606-8501, Japan
| | - Li-Wen Shen
- 2. Lab of Chemical Biology and Molecular Drug Design, College of Pharmaceutical Science, Zhejiang University of Technology, 18 Chaowang Road, Hangzhou, 310014, China
| | - Chuan-He Wei
- 2. Lab of Chemical Biology and Molecular Drug Design, College of Pharmaceutical Science, Zhejiang University of Technology, 18 Chaowang Road, Hangzhou, 310014, China
| | - Nagahiro Minato
- 4. Department of Immunology and Cell Biology, Graduate School of Medicine, Kyoto University, Kyoto, 606-8501, Japan
| | - Wen Zhang
- 2. Lab of Chemical Biology and Molecular Drug Design, College of Pharmaceutical Science, Zhejiang University of Technology, 18 Chaowang Road, Hangzhou, 310014, China
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The γδ T-cell receptor repertoire is reconstituted in HIV patients after prolonged antiretroviral therapy. AIDS 2013; 27:1557-62. [PMID: 23525030 DOI: 10.1097/qad.0b013e3283611888] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE Determine whether reconstitution of Vγ2Vδ2 T cells in patients with HIV is due to new cell synthesis with recovery of the T-cell receptor repertoire or proliferative expansion of residual cells from the time of treatment initiation. DESIGN Perform a cross-sectional analysis of the T-cell receptor complexity of Vγ2 chain in patients treated for HIV, natural virus suppressors who control viremia to undetectable levels, patients with chronic low-level viremia in the absence of therapy, and uninfected controls. Apply quantitative methods for repertoire analysis to assess the degree of Vδ2 repertoire loss or reconstitution. METHODS T-cell receptor Vγ2 chain DNA clones (up to 300 per patient sample) were sequenced and aligned to enumerate the antigen-reactive subset with Vγ2-Jγ1.2 rearrangements. Predominant shared (public) sequences in each patient were compared to a reference library of public sequences from uninfected controls to assess the extent of similarity. Repertoire comparisons were quantified through bioinformatics testing. RESULTS Patients with prolonged virus suppression due to antiretroviral therapy reconstituted the Vγ2 T-cell repertoire to near-normal levels. Natural virus suppressors were similar to the treatment group. Severe defects in the Vγ2 T-cell receptor repertoire were observed in patients with chronic viremia despite the absence of overt disease. CONCLUSION Prolonged HIV suppression with antiretroviral therapy leads to reconstitution of the Vγ2Vδ2 T-cell subset deleted in HIV disease. Direct evidence for repair of the T-cell receptor repertoire supports a view that treatment-associated immune reconstitution is due to new cell synthesis and not to expansion of residual cell populations.
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Depletion and dysfunction of Vγ2Vδ2 T cells in HIV disease: mechanisms, impacts and therapeutic implications. Cell Mol Immunol 2012; 10:42-9. [PMID: 23241900 DOI: 10.1038/cmi.2012.50] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Infection with human immunodeficiency virus (HIV) disrupts the balance among γδ T cell subsets, with increasing Vδ1+ cells and substantial depletion of circulating Vδ2+ cells. Depletion is an indirect effect of HIV in CD4-negative Vδ2 cells, but is specific for phosphoantigen-responsive subpopulations identified by the Vγ2-Jγ1.2 (also called Vγ9-JγP) T cell receptor rearrangement. The extent of cell loss and recovery is related closely to clinical status, with highest levels of functional Vδ2 cells present in virus controllers (undetectable viremia in the absence of antiretroviral therapy). We review the mechanisms and clinical consequences for Vδ2 cell depletion in HIV disease. We address the question of whether HIV-mediated Vδ2 cell depletion, despite being an indirect effect of infection, is an important part of the immune evasion strategy for this virus. The important roles for Vδ2 cells, as effectors and immune regulators, identify key mechanisms affected by HIV and show the strong relationships between Vδ2 cell loss and immunodeficiency disease. This field is moving toward immune therapies based on targeting Vδ2 cells and we now have clear goals and expectations to guide interventional clinical trials.
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The α4β7 integrin binds HIV envelope but does not mediate bystander killing of γδ T cells. Blood 2012; 120:698-9. [PMID: 22822002 DOI: 10.1182/blood-2012-03-420117] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Boudová S, Li H, Sajadi MM, Redfield RR, Pauza CD. Impact of persistent HIV replication on CD4 negative Vγ2Vδ2 T cells. J Infect Dis 2012; 205:1448-55. [PMID: 22454465 DOI: 10.1093/infdis/jis217] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND CD4- Vγ2Vδ2 T cells are depleted during human immunodeficiency virus (HIV) infection but can recover to near normal levels in patients who spontaneously control viremia in the absence of therapy. By contrasting Vγ2Vδ2 T-cell numbers, phenotype, and T-cell receptor (TCR) repertoire, we investigate the dynamic tension between active immunity and progressive T-cell destruction during persistent viremia. METHODS Peripheral blood Vγ2Vδ2 T-cell levels and phenotypes were characterized by flow cytometry. Lymphoproliferation assays measured functional responses. Spectratyping characterized damage to the TCR repertoire. RESULTS Levels, responses to antigen and the proportion of T effector memory Vγ2Vδ2 T cells in patients with persistent viremia, were intermediate between patients with natural virus suppression (NVS) and patients receiving antiretroviral therapy. Damage to the TCR γ-2 chain repertoire and depletion of CD56+ Vγ2Vδ2 T cells were more pronounced in viremic patients, compared with antiretroviral therapy recipients and patients with natural virus suppression. CONCLUSIONS Characteristics of Vγ2Vδ2 T cells in viremic patients reflect both active responses (increasing cell numbers, better antigen responses, and higher proportion of effector memory cells) and ongoing damage (repertoire changes and loss of CD56+ cells). Unlike patients who control viremia to undetectable levels, Vγ2Vδ2 T cells are diminished during persistent viremia and may eventually be lost because of progressive destruction of the TCR repertoire.
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Affiliation(s)
- Sarah Boudová
- Institute of Human Virology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
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HIV envelope-mediated, CCR5/α4β7-dependent killing of CD4-negative γδ T cells which are lost during progression to AIDS. Blood 2011; 118:5824-31. [PMID: 21926353 DOI: 10.1182/blood-2011-05-356535] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
HIV infects and replicates in CD4+ T cells but effects on host immunity and disease also involve depletion, hyper-activation, and modification of CD4-negative cell populations. In particular, the depletion of CD4-negative γδ T cells is common to all HIV+ individuals. We found that soluble or cell-associated envelope glycoproteins from CCR5-tropic strains of HIV could bind, activates the p38-caspase pathway, and induce the death of γδ cells. Envelope binding requires integrin α4β7 and chemokine receptor CCR5 which are at high levels and form a complex on the γδ T cell membrane. This receptor complex facilitated V3 loop binding to CCR5 in the absence of CD4-induced conformational changes. Cell death was increased by antigen stimulation after exposure to envelope glycoprotein. Direct signaling by envelope glycoprotein killed CD4-negative γδ T cells and reproduced a defect observed in all patients with HIV disease.
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