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Ishihara M, Miwa H, Fujiwara H, Akahori Y, Kato T, Tanaka Y, Tawara I, Shiku H. αβ-T cell receptor transduction gives superior mitochondrial function to γδ-T cells with promising persistence. iScience 2023; 26:107802. [PMID: 37720098 PMCID: PMC10502403 DOI: 10.1016/j.isci.2023.107802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 07/25/2023] [Accepted: 08/29/2023] [Indexed: 09/19/2023] Open
Abstract
Adoptive cell therapy using allogeneic γδ-T cells is a promising option for off-the-shelf T cell products with a low risk of graft-versus-host disease (GVHD). Long-term persistence may boost the clinical development of γδ-T cell products. In this study, we found that genetically modified Vγ9+Vδ2+ T cells expressing a tumor antigen-specific αβ-TCR and CD8 coreceptor (GMC) showed target-specific killing and excellent persistence. To determine the mechanisms underlying these promising effects, we investigated metabolic characteristics. Cytokine secretion by γδ-TCR-stimulated nongene-modified γδ-T cells (NGMCs) and αβ-TCR-stimulated GMCs was equally suppressed by a glycolysis inhibitor, although the cytokine secretion of αβ-TCR-stimulated GMCs was more strongly inhibited by ATP synthase inhibitors than that of γδ-TCR-stimulated NGMCs. Metabolomic and transcriptomic analyses, flow cytometry analysis using mitochondria-labeling dyes and extracellular flux analysis consistently suggest that αβ-TCR-transduced γδ-T cells acquire superior mitochondrial function. In conclusion, αβ-TCR-transduced γδ-T cells acquire superior mitochondrial function with promising persistence.
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Affiliation(s)
- Mikiya Ishihara
- Department of Medical Oncology, Mie University Hospital, 2-174 Edobashi, Tsu, Mie 514-8507, Japan
| | - Hiroshi Miwa
- Department of Personalized Cancer Immunotherapy, Mie University Graduate School of Medicine, 1577 Kurimamachiya-cho, Tsu, Mie 514-8507, Japan
| | - Hiroshi Fujiwara
- Department of Personalized Cancer Immunotherapy, Mie University Graduate School of Medicine, 1577 Kurimamachiya-cho, Tsu, Mie 514-8507, Japan
| | - Yasushi Akahori
- Department of Personalized Cancer Immunotherapy, Mie University Graduate School of Medicine, 1577 Kurimamachiya-cho, Tsu, Mie 514-8507, Japan
| | - Takuma Kato
- Department of Cellular and Molecular Immunology, Mie University Graduate School of Medicine, Tsu, Mie 514-8507, Japan
| | - Yoshimasa Tanaka
- Center for Medical Innovation, Nagasaki University, 1-7-1 Sakamoto, Nagasaki 852-8588, Japan
| | - Isao Tawara
- Department of Hematology and Oncology, Mie University Graduate School of Medicine, 2-174 Edobashi, Tsu, Mie 514-8507, Japan
| | - Hiroshi Shiku
- Department of Personalized Cancer Immunotherapy, Mie University Graduate School of Medicine, 1577 Kurimamachiya-cho, Tsu, Mie 514-8507, Japan
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2
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Liang W, Yi R, Wang W, Shi Y, Zhang J, Xu X, Wang Q, Liu M, Wang F. Enhancing the Antitumor Immunity of T Cells by Engineering the Lipid-Regulatory Site of the TCR/CD3 Complex. Cancer Immunol Res 2023; 11:93-108. [PMID: 36265009 DOI: 10.1158/2326-6066.cir-21-1118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 07/24/2022] [Accepted: 10/13/2022] [Indexed: 01/05/2023]
Abstract
The engagement of the T-cell receptor (TCR) by a specific peptide-MHC ligand initiates transmembrane signaling to induce T-cell activation, a key step in most adaptive immune responses. Previous studies have indicated that TCR signaling is tightly regulated by cholesterol and its sulfate metabolite, cholesterol sulfate (CS), on the membrane. Here, we report a novel mechanism by which CS modulates TCR signaling through a conformational change of CD3 subunits. We found that the negatively charged CS interacted with the positively charged cytoplasmic domain of CD3ε (CD3εCD) to enhance its binding to the cell membrane and induce a stable secondary structure. This secondary structure suppressed the release of CD3εCD from the membrane in the presence of Ca2+, which in turn inhibited TCR phosphorylation and signaling. When a point mutation (I/A) was introduced to the intracellular immunoreceptor tyrosine-based activation motifs (YxxI-x6-8-YxxL) of CD3ε subunit, it reduced the stability of the secondary structure and regained sensitivity to Ca2+, which abolished CS-mediated inhibition and enhanced the signaling of the TCR complex. Notably, the I/A mutation could be applied to both murine and human TCR-T cell therapy to improve the antitumor efficacy. Our study reveals insights into the regulatory mechanism of TCR signaling and provides a strategy to functionally engineer the TCR/CD3 complex for T cell-based cancer immunotherapy.
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Affiliation(s)
- Wenhua Liang
- Center for Immune-Related Diseases at Shanghai Institute of Immunology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Department of Immunology and Microbiology, State Key Laboratory of Oncogenes and Related Genes, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Ruirong Yi
- Center for Immune-Related Diseases at Shanghai Institute of Immunology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Department of Immunology and Microbiology, State Key Laboratory of Oncogenes and Related Genes, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Weifang Wang
- Center for Immune-Related Diseases at Shanghai Institute of Immunology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Department of Immunology and Microbiology, State Key Laboratory of Oncogenes and Related Genes, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yiwei Shi
- Center for Immune-Related Diseases at Shanghai Institute of Immunology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Department of Immunology and Microbiology, State Key Laboratory of Oncogenes and Related Genes, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jiqin Zhang
- BRL Medicine, Inc., Shanghai, China.,Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, China
| | - Xiang Xu
- BRL Medicine, Inc., Shanghai, China
| | | | - Mingyao Liu
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, China
| | - Feng Wang
- Center for Immune-Related Diseases at Shanghai Institute of Immunology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Department of Immunology and Microbiology, State Key Laboratory of Oncogenes and Related Genes, Shanghai Jiao Tong University School of Medicine, Shanghai, China
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3
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Colbert JD, Cruz FM, Baer CE, Rock KL. Tetraspanin-5-mediated MHC class I clustering is required for optimal CD8 T cell activation. Proc Natl Acad Sci U S A 2022; 119:e2122188119. [PMID: 36215490 DOI: 10.1073/pnas.2122188119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
MHC molecules are not randomly distributed on the plasma membrane but instead are present in discrete nanoclusters. The mechanisms that control formation of MHC I nanoclusters and the importance of such structures are incompletely understood. Here, we report a molecular association between tetraspanin-5 (Tspan5) and MHC I molecules that started in the endoplasmic reticulum and was maintained on the plasma membrane. This association was observed both in mouse dendritic cells and in human cancer cell lines. Loss of Tspan5 reduced the size of MHC I clusters without affecting MHC I peptide loading, delivery of complexes to the plasma membrane, or overall surface MHC I levels. Functionally, CD8 T cell responses to antigen presented by Tspan5-deficient dendritic cells were impaired but were restored by antibody-induced reclustering of MHC I molecules. In contrast, Tspan5 did not associate with two other plasma membrane proteins, Flotillin1 and CD55, with or the endoplasmic reticulum proteins Tapasin and TAP. Thus, our findings identify a mechanism underlying the clustering of MHC I molecules that is important for optimal T cell responses.
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4
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Zhao X, Wu LZ, Ng EKY, Leow KWS, Wei Q, Gascoigne NRJ, Brzostek J. Non-Stimulatory pMHC Enhance CD8 T Cell Effector Functions by Recruiting Coreceptor-Bound Lck. Front Immunol 2021; 12:721722. [PMID: 34707605 PMCID: PMC8542885 DOI: 10.3389/fimmu.2021.721722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Accepted: 09/20/2021] [Indexed: 11/17/2022] Open
Abstract
Under physiological conditions, CD8+ T cells need to recognize low numbers of antigenic pMHC class I complexes in the presence of a surplus of non-stimulatory, self pMHC class I on the surface of the APC. Non-stimulatory pMHC have been shown to enhance CD8+ T cell responses to low amounts of antigenic pMHC, in a phenomenon called co-agonism, but the physiological significance and molecular mechanism of this phenomenon are still poorly understood. Our data show that co-agonist pMHC class I complexes recruit CD8-bound Lck to the immune synapse to modulate CD8+ T cell signaling pathways, resulting in enhanced CD8+ T cell effector functions and proliferation, both in vitro and in vivo. Moreover, co-agonism can boost T cell proliferation through an extrinsic mechanism, with co-agonism primed CD8+ T cells enhancing Akt pathway activation and proliferation in neighboring CD8+ T cells primed with low amounts of antigen.
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Affiliation(s)
- Xiang Zhao
- Immunology Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Liang-Zhe Wu
- Immunology Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Esther K Y Ng
- Immunology Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Kerisa W S Leow
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Qianru Wei
- Immunology Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Nicholas R J Gascoigne
- Immunology Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Joanna Brzostek
- Immunology Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
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5
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Connolly A, Panes R, Tual M, Lafortune R, Bellemare-Pelletier A, Gagnon E. TMEM16F mediates bystander TCR-CD3 membrane dissociation at the immunological synapse and potentiates T cell activation. Sci Signal 2021; 14:eabb5146. [PMID: 33758060 DOI: 10.1126/scisignal.abb5146] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Electrostatic interactions regulate many aspects of T cell receptor (TCR) activity, including enabling the dynamic binding of the TCR-associated CD3ε and CD3ζ chains to anionic lipids in the plasma membrane to prevent spontaneous phosphorylation. Substantial changes in the electrostatic potential of the plasma membrane occur at the immunological synapse, the interface between a T cell and an antigen-presenting cell. Here, we investigated how the electrostatic interactions that promote dynamic membrane binding of the TCR-CD3 cytoplasmic domains are modulated during signaling and affect T cell activation. We found that Ca2+-dependent activation of the phosphatidylserine scramblase TMEM16F, which was previously implicated in T cell activation, reduced the electrostatic potential of the plasma membrane during immunological synapse formation by locally redistributing phosphatidylserine. This, in turn, increased the dissociation of bystander TCR-CD3 cytoplasmic domains from the plasma membrane and enhanced TCR-dependent signaling and consequently T cell activation. This study establishes the molecular basis for the role of TMEM16F in bystander TCR-induced signal amplification and identifies enhancement of TMEM16F function as a potential therapeutic strategy for promoting T cell activation.
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Affiliation(s)
- Audrey Connolly
- Institut de Recherche en Immunologie et Cancérologie, 2950 Chemin de la Polytechnique, Montréal, Québec H3T1J4, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Faculté de Médecine, Université de Montréal, 2900 Édouard-Montpetit, Montréal, Québec H3T1J4, Canada
| | - Rébecca Panes
- Institut de Recherche en Immunologie et Cancérologie, 2950 Chemin de la Polytechnique, Montréal, Québec H3T1J4, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Faculté de Médecine, Université de Montréal, 2900 Édouard-Montpetit, Montréal, Québec H3T1J4, Canada
| | - Margaux Tual
- Institut de Recherche en Immunologie et Cancérologie, 2950 Chemin de la Polytechnique, Montréal, Québec H3T1J4, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Faculté de Médecine, Université de Montréal, 2900 Édouard-Montpetit, Montréal, Québec H3T1J4, Canada
| | - Raphaël Lafortune
- Département de Microbiologie, Infectiologie et Immunologie, Faculté de Médecine, Université de Montréal, 2900 Édouard-Montpetit, Montréal, Québec H3T1J4, Canada
| | - Angélique Bellemare-Pelletier
- Institut de Recherche en Immunologie et Cancérologie, 2950 Chemin de la Polytechnique, Montréal, Québec H3T1J4, Canada
| | - Etienne Gagnon
- Institut de Recherche en Immunologie et Cancérologie, 2950 Chemin de la Polytechnique, Montréal, Québec H3T1J4, Canada.
- Département de Microbiologie, Infectiologie et Immunologie, Faculté de Médecine, Université de Montréal, 2900 Édouard-Montpetit, Montréal, Québec H3T1J4, Canada
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6
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Abstract
After selection in the thymus, the post-thymic T cell compartments comprise heterogenous subsets of naive and memory T cells that make continuous T cell receptor (TCR) contact with self-ligands bound to major histocompatibility complex (MHC) molecules. T cell recognition of self-MHC ligands elicits covert TCR signaling and is particularly important for controlling survival of naive T cells. Such tonic TCR signaling is tightly controlled and maintains the cells in a quiescent state to avoid autoimmunity. Here, we review how naive and memory T cells are differentially tuned and wired for TCR sensitivity to self and foreign ligands.
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Affiliation(s)
- Jae-Ho Cho
- Academy of Immunology and Microbiology, Institute for Basic Science, Pohang, Korea.,Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, Pohang, Korea
| | - Jonathan Sprent
- Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, Pohang, Korea.,Immunology Research Program, Garvan Institute of Medical Research, Darlinghurst, NSW, Australia
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7
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Anikeeva N, Fischer NO, Blanchette CD, Sykulev Y. Extent of MHC Clustering Regulates Selectivity and Effectiveness of T Cell Responses. J Immunol 2018; 202:591-597. [PMID: 30541879 DOI: 10.4049/jimmunol.1801196] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Accepted: 11/09/2018] [Indexed: 11/19/2022]
Abstract
MHC proteins that present peptide ligands for recognition by TCR form nanoscale clusters on the cell membrane of APCs. How the extent of MHC clustering controls productive TCR engagement and TCR-mediated signaling has not been systematically studied. To evaluate the role of MHC clustering, we exploited nanoscale discoidal membrane mimetics (nanolipoprotein particles) to capture and present peptide-MHC (pMHC) ligands at various densities. We examined the binding of these model membrane clusters to the surface of live human CD8+ T cells and the subsequent triggering of intracellular signaling. The data demonstrate that the proximity of pMHC ligands, high association rate of CD8-MHC interactions, and relatively long lifetime of cognate TCR-pMHC complexes emerge as essential parameters, explaining the significance of MHC clustering. Rapid rebinding of CD8 to MHC suggests a dual role of CD8 in facilitating the T cells' hunt for a rare foreign pMHC ligand and the induction of rapid T cell response. Thus, our findings provide a new understanding of how MHC clustering influences multivalent interactions of pMHC ligands with CD8 and TCR on live T cells that regulate Ag recognition, kinetics of intracellular signaling, and the selectivity and efficiency of T cell responses.
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Affiliation(s)
- Nadia Anikeeva
- Department of Microbiology and Immunology and Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107; and
| | - Nicholas O Fischer
- Biosciences and Biotechnology Division, Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94551
| | - Craig D Blanchette
- Biosciences and Biotechnology Division, Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94551
| | - Yuri Sykulev
- Department of Microbiology and Immunology and Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107; and
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8
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Zhao X, Sankaran S, Yap J, Too CT, Ho ZZ, Dolton G, Legut M, Ren EC, Sewell AK, Bertoletti A, MacAry PA, Brzostek J, Gascoigne NRJ. Nonstimulatory peptide-MHC enhances human T-cell antigen-specific responses by amplifying proximal TCR signaling. Nat Commun 2018; 9:2716. [PMID: 30006605 PMCID: PMC6045629 DOI: 10.1038/s41467-018-05288-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Accepted: 05/12/2018] [Indexed: 01/02/2023] Open
Abstract
Foreign antigens are presented by antigen-presenting cells in the presence of abundant endogenous peptides that are nonstimulatory to the T cell. In mouse T cells, endogenous, nonstimulatory peptides have been shown to enhance responses to specific peptide antigens, a phenomenon termed coagonism. However, whether coagonism also occurs in human T cells is unclear, and the molecular mechanism of coagonism is still under debate since CD4 and CD8 coagonism requires different interactions. Here we show that the nonstimulatory, HIV-derived peptide GAG enhances a specific human cytotoxic T lymphocyte response to HBV-derived epitopes presented by HLA-A*02:01. Coagonism in human T cells requires the CD8 coreceptor, but not T-cell receptor (TCR) binding to the nonstimulatory peptide–MHC. Coagonists enhance the phosphorylation and recruitment of several molecules involved in the TCR-proximal signaling pathway, suggesting that coagonists promote T-cell responses to antigenic pMHC by amplifying TCR-proximal signaling. Coagonism, the ability of nonstimulatory antigens to promote T-cell activation, has been reported in mice. Here the authors show that coagonism also occurs in human CD8 T cells, in which a nonstimulatory HIV GAG peptide enhances a specific T-cell response to a hepatitis B virus epitope by amplifying T-cell receptor signals.
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Affiliation(s)
- Xiang Zhao
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore, 117545, Singapore
| | - Shvetha Sankaran
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore, 117545, Singapore.,Immunology Programme, Life Sciences Institute, National University of Singapore, 28 Medical Drive, Centre for Life Sciences, Level 3, Singapore, 117456, Singapore
| | - Jiawei Yap
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore, 117545, Singapore
| | - Chien Tei Too
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore, 117545, Singapore.,Immunology Programme, Life Sciences Institute, National University of Singapore, 28 Medical Drive, Centre for Life Sciences, Level 3, Singapore, 117456, Singapore
| | - Zi Zong Ho
- Emerging Infectious Diseases Program, Duke-NUS Graduate Medical School, 8 College Road, Singapore, 169857, Singapore
| | - Garry Dolton
- Division of Infection and Immunity, Cardiff University School of Medicine, Henry Wellcome Building, University Hospital Wales, Heath Park, Cardiff, CF14 4XN, United Kingdom
| | - Mateusz Legut
- Division of Infection and Immunity, Cardiff University School of Medicine, Henry Wellcome Building, University Hospital Wales, Heath Park, Cardiff, CF14 4XN, United Kingdom
| | - Ee Chee Ren
- Singapore Immunology Network, A*STAR, 8A Biomedical Grove, Immunos #03-06, Singapore, 138648, Singapore
| | - Andrew K Sewell
- Division of Infection and Immunity, Cardiff University School of Medicine, Henry Wellcome Building, University Hospital Wales, Heath Park, Cardiff, CF14 4XN, United Kingdom.,Systems Immunity Research Institute, Cardiff University, Tenovus Building, Cardiff, CF14 4XN, United Kingdom
| | - Antonio Bertoletti
- Emerging Infectious Diseases Program, Duke-NUS Graduate Medical School, 8 College Road, Singapore, 169857, Singapore
| | - Paul A MacAry
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore, 117545, Singapore.,Immunology Programme, Life Sciences Institute, National University of Singapore, 28 Medical Drive, Centre for Life Sciences, Level 3, Singapore, 117456, Singapore.,NUS Graduate School for Integrative Sciences and Engineering (NGS), National University of Singapore, Centre for Life Sciences (CeLS), #05-01, 28 Medical Drive, Singapore, 117456, Singapore
| | - Joanna Brzostek
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore, 117545, Singapore.
| | - Nicholas R J Gascoigne
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore, 117545, Singapore. .,Immunology Programme, Life Sciences Institute, National University of Singapore, 28 Medical Drive, Centre for Life Sciences, Level 3, Singapore, 117456, Singapore. .,NUS Graduate School for Integrative Sciences and Engineering (NGS), National University of Singapore, Centre for Life Sciences (CeLS), #05-01, 28 Medical Drive, Singapore, 117456, Singapore.
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9
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Abstract
Thymocyte selection involves the positive and negative selection of the repertoire of T cell receptors (TCRs) such that the organism does not suffer autoimmunity, yet has the benefit of the ability to recognize any invading pathogen. The signal transduced through the TCR is translated into a number of different signaling cascades that result in transcription factor activity in the nucleus and changes to the cytoskeleton and motility. Negative selection involves inducing apoptosis in thymocytes that express strongly self-reactive TCRs, whereas positive selection must induce survival and differentiation programs in cells that are more weakly self-reactive. The TCR recognition event is analog by nature, but the outcome of signaling is not. A large number of molecules regulate the strength of the TCR-derived signal at various points in the cascades. This review discusses the various factors that can regulate the strength of the TCR signal during thymocyte development.
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Affiliation(s)
- Nicholas R J Gascoigne
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, and Immunology Program, National University of Singapore, Singapore 11759;
| | - Vasily Rybakin
- Laboratory of Immunobiology, REGA Institute, Department of Microbiology and Immunology, KU Leuven, Leuven 3000, Belgium
| | - Oreste Acuto
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, United Kingdom
| | - Joanna Brzostek
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, and Immunology Program, National University of Singapore, Singapore 11759;
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10
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Kim HO, Cho JH. T Cell's Sense of Self: a Role of Self-Recognition in Shaping Functional Competence of Naïve T Cells. Immune Netw 2017; 17:201-213. [PMID: 28860950 PMCID: PMC5577298 DOI: 10.4110/in.2017.17.4.201] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Revised: 08/09/2017] [Accepted: 08/11/2017] [Indexed: 01/05/2023] Open
Abstract
Post-thymic naïve T cells constitute a key cellular arm of adaptive immunity, with a well-known characteristic of the specificity and robustness of responses to cognate foreign antigens which is presented as a form of antigen-derived peptides bound to major histocompatibility complex (MHC) molecules by antigen-presenting cells (APCs). In a steady state, however, these cells are resting, quiescent in their activity, but must keep full ranges of functional integrity to mount rapid and robust immunity to cope with various infectious pathogens at any time and space. Such unique property of resting naïve T cells is not acquired in a default manner but rather requires an active mechanism. Although our understanding of exactly how this process occurs and what factors are involved remains incomplete, a particular role of self-recognition by T cells has grown greatly in recent years. In this brief review, we discuss recent data on how the interaction of T cells with self-peptide MHC ligands regulates their functional responsiveness and propose that variable strength of self-reactivity imposes distinctly different levels of functional competence and heterogeneity.
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Affiliation(s)
- Hee-Ok Kim
- Academy of Immunology and Microbiology, Institute for Basic Science, Pohang 37673, Korea.,Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, Pohang 37673, Korea
| | - Jae-Ho Cho
- Academy of Immunology and Microbiology, Institute for Basic Science, Pohang 37673, Korea.,Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, Pohang 37673, Korea
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11
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Spencer CT, Bezbradica JS, Ramos MG, Arico CD, Conant SB, Gilchuk P, Gray JJ, Zheng M, Niu X, Hildebrand W, Link AJ, Joyce S. Viral infection causes a shift in the self peptide repertoire presented by human MHC class I molecules. Proteomics Clin Appl 2016; 9:1035-52. [PMID: 26768311 DOI: 10.1002/prca.201500106] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2015] [Revised: 10/26/2015] [Accepted: 10/29/2015] [Indexed: 12/22/2022]
Abstract
PURPOSE MHC class I presentation of peptides allows T cells to survey the cytoplasmic protein milieu of host cells. During infection, presentation of self peptides is, in part, replaced by presentation of microbial peptides. However, little is known about the self peptides presented during infection, despite the fact that microbial infections alter host cell gene expression patterns and protein metabolism. EXPERIMENTAL DESIGN The self peptide repertoire presented by HLA-A*01;01, HLA-A*02;01, HLA-B*07;02, HLA-B*35;01, and HLA-B*45;01 (where HLA is human leukocyte antigen) was determined by tandem MS before and after vaccinia virus infection. RESULTS We observed a profound alteration in the self peptide repertoire with hundreds of self peptides uniquely presented after infection for which we have coined the term "self peptidome shift." The fraction of novel self peptides presented following infection varied for different HLA class I molecules. A large part (approximately 40%) of the self peptidome shift arose from peptides derived from type I interferon-inducible genes, consistent with cellular responses to viral infection. Interestingly, approximately 12% of self peptides presented after infection showed allelic variation when searched against approximately 300 human genomes. CONCLUSION AND CLINICAL RELEVANCE Self peptidome shift in a clinical transplant setting could result in alloreactivity by presenting new self peptides in the context of infection-induced inflammation.
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Affiliation(s)
- Charles T Spencer
- Department of Biological Sciences, University of Texas at El Paso, El Paso, TX, USA
| | - Jelena S Bezbradica
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Australia
| | - Mireya G Ramos
- Department of Biological Sciences, University of Texas at El Paso, El Paso, TX, USA
| | - Chenoa D Arico
- Department of Biological Sciences, University of Texas at El Paso, El Paso, TX, USA
| | - Stephanie B Conant
- Department of Pathology, Microbiology and Immunology, Nashville, TN, USA
| | - Pavlo Gilchuk
- Department of Pathology, Microbiology and Immunology, Nashville, TN, USA.,Veterans Administration Tennessee Valley Healthcare System, Nashville, TN, USA
| | - Jennifer J Gray
- Department of Pathology, Microbiology and Immunology, Nashville, TN, USA
| | - Mu Zheng
- Department of Pathology, Microbiology and Immunology, Nashville, TN, USA.,Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Xinnan Niu
- Department of Pathology, Microbiology and Immunology, Nashville, TN, USA.,Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - William Hildebrand
- Department of Microbiology and Immunology, University of Oklahoma Health Science Centre, Oklahoma City, OK, USA
| | - Andrew J Link
- Department of Pathology, Microbiology and Immunology, Nashville, TN, USA.,Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Sebastian Joyce
- Department of Pathology, Microbiology and Immunology, Nashville, TN, USA.,Veterans Administration Tennessee Valley Healthcare System, Nashville, TN, USA
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12
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13
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Abstract
Molecular interactions at the interface between helper T cells and antigen-presenting B cells govern the ability to produce specific antibodies, which is a central event in protective immunity generated by natural infection or man-made vaccines. In order for a T cell to deliver effective help to a B cell and guide affinity maturation, it needs to provide feedback that is proportional to the amount of antigen the B cell collects with its surface antibody. This review focuses on mechanisms by which T and B cells manage to count the products of antigen capture and encourage B cells with the best receptors to dominate the response and make antibody-producing plasma cells. We discuss what is known about the proportionality of T cells responses to presented antigens and consider the mechanisms that B cells may use to keep count of positive feedback from T cells.
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Affiliation(s)
- Michael L Dustin
- Kennedy Institute of Rheumatology, Nuffield Department of Orthopedics, Rheumatology, and Musculoskeletal Sciences, The University of Oxford, Roosevelt Drive, Headington OX3 7FY, UK; Skirball Institute of Biomolecular Medicine, Department of Pathology, New York University School of Medicine, 540 First Avenue, New York, NY 10016, USA.
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14
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Hoerter JAH, Brzostek J, Artyomov MN, Abel SM, Casas J, Rybakin V, Ampudia J, Lotz C, Connolly JM, Chakraborty AK, Gould KG, Gascoigne NRJ. Coreceptor affinity for MHC defines peptide specificity requirements for TCR interaction with coagonist peptide-MHC. ACTA ACUST UNITED AC 2013; 210:1807-21. [PMID: 23940257 PMCID: PMC3754861 DOI: 10.1084/jem.20122528] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The requirement for the TCR to interact with coagonists, endogenous MHC–peptide complexes which do not themselves activate the T cell, decreases as the strength of the CD8–class I interaction increases. Recent work has demonstrated that nonstimulatory endogenous peptides can enhance T cell recognition of antigen, but MHCI- and MHCII-restricted systems have generated very different results. MHCII-restricted TCRs need to interact with the nonstimulatory peptide–MHC (pMHC), showing peptide specificity for activation enhancers or coagonists. In contrast, the MHCI-restricted cells studied to date show no such peptide specificity for coagonists, suggesting that CD8 binding to noncognate MHCI is more important. Here we show how this dichotomy can be resolved by varying CD8 and TCR binding to agonist and coagonists coupled with computer simulations, and we identify two distinct mechanisms by which CD8 influences the peptide specificity of coagonism. Mechanism 1 identifies the requirement of CD8 binding to noncognate ligand and suggests a direct relationship between the magnitude of coagonism and CD8 affinity for coagonist pMHCI. Mechanism 2 describes how the affinity of CD8 for agonist pMHCI changes the requirement for specific coagonist peptides. MHCs that bind CD8 strongly were tolerant of all or most peptides as coagonists, but weaker CD8-binding MHCs required stronger TCR binding to coagonist, limiting the potential coagonist peptides. These findings in MHCI systems also explain peptide-specific coagonism in MHCII-restricted cells, as CD4–MHCII interaction is generally weaker than CD8–MHCI.
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Affiliation(s)
- John A H Hoerter
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, CA 92037, USA
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15
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François P, Voisinne G, Siggia ED, Altan-Bonnet G, Vergassola M. Phenotypic model for early T-cell activation displaying sensitivity, specificity, and antagonism. Proc Natl Acad Sci U S A 2013; 110:E888-97. [PMID: 23431198 DOI: 10.1073/pnas.1300752110] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Early T-cell activation is selected by evolution to discriminate a few foreign peptides rapidly from a vast excess of self-peptides, and it is unclear in quantitative terms how this is possible. We show that a generic proofreading cascade supplemented by a single negative feedback mediated by the Src homology 2 domain phosphatase-1 (SHP-1) accounts quantitatively for early T-cell activation, including the effects of antagonists. Modulation of the negative feedback with SHP-1 concentration explains counterintuitive experimental observations, such as the nonmonotonic behavior of receptor activity on agonist concentration, the digital vs. continuous behavior on certain parameters, and the loss of response for high SHP-1 concentration. New experiments validate predictions on the nontrivial joint dependence on binding time and concentration for the relative effect of two antagonists: We explain why strong antagonists behave as partial agonists at low concentration and predict that the relative effect of antagonists can invert as their concentrations are varied. By focusing on the phenotype, our model quantitatively fits a body of experimental data with minimal variables and parameters.
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16
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Abstract
Naive T cells continuously migrate between the circulatory system and lymphoid organs, where they make dynamic contacts with rare dendritic cells (DCs) that strategically form an extensive dendrite network. In such a scenario, T cells spend most of their time quickly scanning the antigenic content of multiple DCs. These interactions provide the basis for efficient adaptive responses by increasing the probability of encounters between rare antigen-specific T cells and those DCs presenting the respective cognate antigens. In the absence of foreign antigen, however, T cells show different degrees of functional sensitivity toward TCR stimulation. Scanning of MHC/self-peptide complexes by naive T cells in the absence of infection is not without consequences but it increases their subsequent response toward antigenic challenge. This indicates that TCR sensitivity in naive T cells is tuned depending on the MHC/self-peptide signals they integrate from the environment even before T cells encounter cognate antigen. DCs have emerged as key components in providing MHC/self-peptide complexes and increasing the sensitivity of T cells toward subsequent TCR triggering. In the absence of cognate antigen, DCs maintain a tonic TCR signaling and license T cells for immune synapse (IS) maturation resulting in enhanced T cell responses toward a subsequent antigen stimulation. This review discusses recent findings on this subject and highlights the importance of the DC pool size for optimal T cell awareness to foreign antigen.
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Affiliation(s)
- Natalio Garbi
- Department of Molecular Immunology, Institutes of Molecular Medicine and Experimental Immunology, University of Bonn Bonn, Germany
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17
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Anikeeva N, Gakamsky D, Schøller J, Sykulev Y. Evidence that the density of self peptide-MHC ligands regulates T-cell receptor signaling. PLoS One 2012; 7:e41466. [PMID: 22870225 PMCID: PMC3411518 DOI: 10.1371/journal.pone.0041466] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2012] [Accepted: 06/21/2012] [Indexed: 11/24/2022] Open
Abstract
Noncognate or self peptide-MHC (pMHC) ligands productively interact with T-cell receptor (TCR) and are always in a large access over the cognate pMHC on the surface of antigen presenting cells. We assembled soluble cognate and noncognate pMHC class I (pMHC-I) ligands at designated ratios on various scaffolds into oligomers that mimic pMHC clustering and examined how multivalency and density of the pMHCs in model clusters influences the binding to live CD8 T cells and the kinetics of TCR signaling. Our data demonstrate that the density of self pMHC-I proteins promotes their interaction with CD8 co-receptor, which plays a critical role in recognition of a small number of cognate pMHC-I ligands. This suggests that MHC clustering on live target cells could be utilized as a sensitive mechanism to regulate T cell responsiveness.
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Affiliation(s)
- Nadia Anikeeva
- Department of Microbiology and Immunology and Kimmel Cancer Institute, Thomas Jefferson University, Philadelphia, Pennsylvania, United States of America
| | | | | | - Yuri Sykulev
- Department of Microbiology and Immunology and Kimmel Cancer Institute, Thomas Jefferson University, Philadelphia, Pennsylvania, United States of America
- * E-mail:
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18
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Abstract
Cytotoxic T lymphocytes (CTL) play a critical role in immunity against viruses and cancer. The antigen receptor or T-cell receptor (TCR) on CTL determines the specificity toward target cells. The CD8 co-receptor functions in concert with the TCR to enhance TCR-mediated signaling, accounting for the remarkable sensitivity and swift signaling kinetics of the CTL response. The latter ensures efficient delivery and release of lytic granules, resulting in sensitive and rapid destruction of target cells.
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Affiliation(s)
- Nadia Anikeeva
- Department of Microbiology and Immunology, Kimmel Cancer Center and Jefferson Vaccine Center, Thomas Jefferson University, Philadelphia, PA 19107, USA.
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Rybakin V, Clamme JP, Ampudia J, Yachi PP, Gascoigne NR. CD8αα and -αβ isotypes are equally recruited to the immunological synapse through their ability to bind to MHC class I. EMBO Rep 2011; 12:1251-6. [PMID: 22081144 DOI: 10.1038/embor.2011.209] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2011] [Revised: 09/22/2011] [Accepted: 09/23/2011] [Indexed: 11/08/2022] Open
Abstract
Bimolecular fluorescence complementation was used to engineer CD8 molecules so that CD8αα and CD8αβ dimers can be independently visualized on the surface of a T cell during antigen recognition. Using this approach, we show that CD8αα is recruited to the immunological synapse almost as well as CD8αβ, but because the kinase Lck associates preferentially with CD8αβ in lipid rafts, CD8αα is the weaker co-receptor. During recognition of the strong CD8αα ligand H2-TL, CD8αα is preferentially recruited. Thus, recruitment of the two CD8 species correlates with their relative binding to the available ligands, rather than with the co-receptor functions of the CD8 species.
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20
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Stone JD, Aggen DH, Chervin AS, Narayanan S, Schmitt TM, Greenberg PD, Kranz DM. Opposite effects of endogenous peptide-MHC class I on T cell activity in the presence and absence of CD8. J Immunol 2011; 186:5193-200. [PMID: 21451107 DOI: 10.4049/jimmunol.1003755] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Nonstimulatory or endogenous peptide-MHC (pepMHC) presented on the surfaces of APCs, either alone or alongside agonist pepMHC, plays various roles in T cell selection and activation. To examine these properties in more detail, we explored several model systems of TCR and pepMHC ligands with sufficient affinity to be activated in the absence of CD8. The TCRs had a range of affinities for agonist and nonstimulatory ligands and were restricted by MHC class I alleles with different properties. We observed CD8-independent antagonism from TCR-pepMHC interactions with very low affinities (e.g., K(D) = 300 μM). In addition, endogenous peptide-L(d) complexes on APCs antagonized activation of coreceptor (CD8)-negative 2C T cells even by the strong agonist QL9-L(d). In contrast, TCRs m33 and 3D-PYY, restricted by K(b) and D(b), respectively, did not show signs of antagonism by endogenous pepMHC in the absence of CD8. This did not appear to be an inherent difference in the ability of the TCRs to be antagonized, as altered peptide ligands could antagonize each TCR. In the presence of CD8, endogenous pepMHC ligands acted in some cases as coagonists. These results show that endogenous pepMHC molecules exhibit complex behavior in T cells, leading to either reduced activity (e.g., in cases of low coreceptor levels) or enhanced activity (e.g., in presence of coreceptor). The behavior may be influenced by the ability of different TCRs to recognize endogenous pepMHC but also perhaps by the inherent properties of the presenting MHC allele.
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Affiliation(s)
- Jennifer D Stone
- Department of Biochemistry, University of Illinois Urbana-Champaign, Urbana, IL 61801, USA.
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21
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Sakamoto N, Rosenberg AS. Apolipoprotein B binding domains: evidence that they are cell-penetrating peptides that efficiently deliver antigenic peptide for cross-presentation of cytotoxic T cells. J Immunol 2011; 186:5004-11. [PMID: 21402897 DOI: 10.4049/jimmunol.1003557] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Low-density lipoproteins (LDLs) are a good source of cholesterol, which is important in cellular homeostasis and production of steroids. Apolipoprotein B-100 (ApoB-100), the sole protein component of LDL, is known to bind to cell surface LDL receptor (LDLR) or cell surface-bound proteoglycans and to be internalized into cells. We found that APCs, consisting of macrophages and dendritic cells, upregulate LDLR on culture in vitro without obvious stimulation. In contrast, T cell populations only upregulate LDLR on activation. Thus, we strategized that tagging immunogens to ApoB-100 might be a useful means to target Ag to APCs. We generated fusion proteins consisting of receptor binding sites in ApoB-100, coupled to OVA peptide (ApoB-OVA), as Ag delivery vehicles and demonstrated that this novel delivery method successfully cross-presented OVA peptides in eliciting CTL responses. Surprisingly, internalization of ApoB-OVA peptide occurred via cell surface proteoglycans rather than LDLRs, consistent with evidence that structural elements of ApoB-100 indicate it to have cell-penetrating peptide properties. Finally, we used this strategy to assess therapeutic vaccination in a tumor setting. OVA-expressing EL-4 tumors grew progressively in mice immunized with ApoB-100 alone but regressed in mice immunized with ApoB-OVA fusion protein, coinciding with development of OVA-specific CTLs. Thus, to our knowledge, this is the first article to describe the cell-penetrating properties of a conserved human origin cell penetrating peptide that may be harnessed as a novel vaccination strategy as well as a therapeutics delivery device.
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Affiliation(s)
- Norihisa Sakamoto
- Division of Therapeutic Proteins, Center for Drug Evaluation and Research, U.S. Food and Drug Administration, Bethesda, MD 20892, USA.
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22
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Abstract
T cell receptor signaling allows the developing thymocyte to undergo positive or negative selection, which is required for the formation of a useful mature T cell repertoire. Recent developments include the finding that much of the Lck kinase (required to initiate T cell signaling) is already in an active configuration before signaling. The analog strength of antigen binding to the T cell receptor binding may be translated into a digital signal by the amount of time the TCR is paired with a co-receptor carrying Lck. Downstream, the cellular localization of MAP kinase signaling is determined by the strength of the signal and in turn predicts positive or negative selection. A novel protein, Themis, is important in crossing the positive selection developmental checkpoint, but its mode of action is still uncertain. Commitment to the CD4 or CD8 lineage is influenced by the amount of ZAP-70 signaling and also by closely regulated responsiveness to intrathymic cytokines such as IL7.
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Affiliation(s)
- Nicholas R J Gascoigne
- Department of Immunology and Microbial Science, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.
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23
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Juang J, Ebert PJR, Feng D, Garcia KC, Krogsgaard M, Davis MM. Peptide-MHC heterodimers show that thymic positive selection requires a more restricted set of self-peptides than negative selection. ACTA ACUST UNITED AC 2010; 207:1223-34. [PMID: 20457759 PMCID: PMC2882826 DOI: 10.1084/jem.20092170] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
T cell selection and maturation in the thymus depends on the interactions between T cell receptors (TCRs) and different self-peptide-major histocompatibility complex (pMHC) molecules. We show that the affinity of the OT-I TCR for its endogenous positively selecting ligands, Catnb-H-2Kb and Cappa1-H-2Kb, is significantly lower than for previously reported positively selecting altered peptide ligands. To understand how these extremely weak endogenous ligands produce signals in maturing thymocytes, we generated soluble monomeric and dimeric peptide-H-2Kb ligands. Soluble monomeric ovalbumin (OVA)-Kb molecules elicited no detectable signaling in OT-I thymocytes, whereas heterodimers of OVA-Kb paired with positively selecting or nonselecting endogenous peptides, but not an engineered null peptide, induced deletion. In contrast, dimer-induced positive selection was much more sensitive to the identity of the partner peptide. Catnb-Kb-Catnb-Kb homodimers, but not heterodimers of Catnb-Kb paired with a nonselecting peptide-Kb, induced positive selection, even though both ligands bind the OT-I TCR with detectable affinity. Thus, both positive and negative selection can be driven by dimeric but not monomeric ligands. In addition, positive selection has much more stringent requirements for the partner self-pMHC.
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Affiliation(s)
- Jeremy Juang
- The Department of Microbiology and Immunology, Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
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24
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Abstract
The T cell receptor (TCR) is responsible for discriminating between self- and foreign-derived peptides, translating minute differences in amino-acid sequence into large differences in response. Because of the great variability in the TCR and its ligands, activation of T cells by foreign peptides is a quantitative process, dependent on a mix of upstream signals and downstream integration. Accordingly, quantitative data and computational models have shed light on many important aspects of this process: molecular noise in ligand recognition, spatial dynamics in T cell-APC (antigen presenting cell) interactions, graded versus all-or-none decision making by the TCR apparatus, mechanisms of peptide antagonism and synergism, and the tunability and robustness of activation thresholds. Though diverse in their formalism, these studies together paint a picture of how modeling has shaped and will continue to shape understanding of T cell immunobiology.
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Affiliation(s)
- Jesse Coward
- Programs in Computational Biology and Immunology, ImmunoDynamics Group, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA
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25
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Abstract
The co-receptors CD4 and CD8 are important in the activation of T cells primarily because of their ability to interact with the proteins of the MHC enhancing recognition of the MHC-peptide complex by the T cell receptor (TCR). An antigen-presenting cell presents a small number of antigenic peptides on its MHC molecules, in the presence of a much larger number of endogenous, mostly nonstimulatory, peptides. Recent work has demonstrated that these endogenous MHC-peptide complexes have an important role in modulating the sensitivity of the TCR. But the role of the endogenous nonstimulatory MHC-peptide complexes differs in MHC class I and class II-restricted T cells. This chapter discusses the data on the role of CD4 or CD8 co-receptors in T cell activation at the immunological synapse, and the role of non stimulatory MHC-peptide complexes in aiding antigen recognition.
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26
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Abstract
For over three decades now, the T cell receptor (TCR) for antigen has not ceased to challenge the imaginations of cellular and molecular immunologists alike. T cell antigen recognition transcends every aspect of adaptive immunity: it shapes the T cell repertoire in the thymus and directs T cell-mediated effector functions in the periphery, where it is also central to the induction of peripheral tolerance. Yet, despite its central position, there remain many questions unresolved: how can one TCR be specific for one particular peptide-major histocompatibility complex (pMHC) ligand while also binding other pMHC ligands with an immunologically relevant affinity? And how can a T cell's extreme specificity (alterations of single methyl groups in their ligand can abrogate a response) and sensitivity (single agonist ligands on a cell surface are sufficient to trigger a measurable response) emerge from TCR-ligand interactions that are so low in affinity? Solving these questions is intimately tied to a fundamental understanding of molecular recognition dynamics within the many different contexts of various T cell-antigen presenting cell (APC) contacts: from the thymic APCs that shape the TCR repertoire and guide functional differentiation of developing T cells to the peripheral APCs that support homeostasis and provoke antigen responses in naïve, effector, memory, and regulatory T cells. Here, we discuss our recent findings relating to T cell antigen recognition and how this leads to the thymic development of foreign-antigen-responsive alphabetaT cells.
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Affiliation(s)
- Peter J R Ebert
- The Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, USA
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27
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Perreault C. The Origin and Role of MHC Class I-Associated Self-Peptides. Progress in Molecular Biology and Translational Science 2010; 92:41-60. [DOI: 10.1016/s1877-1173(10)92003-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Abstract
The peripheral naive T cell pool is fairly stable in number, diversity and functional competence in the absence of vigorous immune responses. However, this apparent tranquility is not an intrinsic property of T cells but involves continuous tuning of the T cell pool composition by homeostatic signals. In the past decade, studies have revealed that naive T cells rely on combinatorial signals from self-peptide-MHC complexes and interleukin-7 for their physical and functional maintenance. Competition for these factors dictates T cell 'space'. In addition, recent studies show that these and other homeostatic factors are offered to T cells on stromal cell networks, which also serve to guide T cell trafficking in secondary lymphoid organs. Such findings suggest the importance of 'place' in the perception and integration of homeostatic cues for the maintenance and functional tuning of the naive T cell pool.
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29
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Ebert PJR, Jiang S, Xie J, Li QJ, Davis MM. An endogenous positively selecting peptide enhances mature T cell responses and becomes an autoantigen in the absence of microRNA miR-181a. Nat Immunol 2009; 10:1162-9. [PMID: 19801983 PMCID: PMC3762483 DOI: 10.1038/ni.1797] [Citation(s) in RCA: 209] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2009] [Accepted: 09/01/2009] [Indexed: 11/09/2022]
Abstract
Thymic positive selection is based on the interactions of T cell antigen receptors (TCRs) with self peptide-major histocompatibility complex (MHC) ligands, but the identity of selecting peptides for MHC class II-restricted TCRs and the functional consequences of this peptide specificity are not clear. Here we identify several endogenous self peptides that positively selected the MHC class II-restricted 5C.C7 TCR. The most potent of these also enhanced mature T cell activation, which supports the hypothesis that one function of positive selection is to produce T cells that can use particular self peptide-MHC complexes for activation and/or homeostasis. We also show that inhibiting the microRNA miR-181a resulted in maturation of T cells that overtly reacted toward these erstwhile positively selecting peptides. Therefore, miR-181a helps to guarantee the clonal deletion of particular moderate-affinity clones by modulating the TCR signaling threshold of thymocytes.
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Affiliation(s)
- Peter J R Ebert
- The Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, California, USA
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30
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Takada K, Jameson SC. Self-class I MHC molecules support survival of naive CD8 T cells, but depress their functional sensitivity through regulation of CD8 expression levels. ACTA ACUST UNITED AC 2009; 206:2253-69. [PMID: 19752186 PMCID: PMC2757867 DOI: 10.1084/jem.20082553] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Previous studies have suggested that naive CD8 T cells require self-peptide–major histocompatability complex (MHC) complexes for maintenance. However, interpretation of such studies is complicated because of the involvement of lymphopenic animals, as lymphopenia drastically alters naive T cell homeostasis and function. In this study, we explored naive CD8 T cell survival and function in nonlymphopenic conditions by using bone marrow chimeric donors and hosts in which class I MHC expression is absent or limited to radiosensitive versus radioresistant cells. We found that long-term survival of naive CD8 T cells (but not CD4 T cells) was impaired in the absence of class I MHC. However, distinct from this effect, class I MHC deprivation also enhanced naive CD8 T cell responsiveness to low-affinity (but not high-affinity) peptide–MHC ligands. We found that this improved sensitivity was a consequence of up-regulated CD8 levels, which was mediated through a transcriptional mechanism. Hence, our data suggest that, in a nonlymphopenic setting, self-class I MHC molecules support CD8 T cell survival, but that these interactions also attenuate naive T cell sensitivity by dynamic tuning of CD8 levels.
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Affiliation(s)
- Kensuke Takada
- Center for Immunology, Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, MN 55455, USA
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31
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Fu G, Vallée S, Rybakin V, McGuire MV, Ampudia J, Brockmeyer C, Salek M, Fallen PR, Hoerter JA, Munshi A, Huang YH, Hu J, Fox HS, Sauer K, Acuto O, Gascoigne NR. Themis controls thymocyte selection through regulation of T cell antigen receptor-mediated signaling. Nat Immunol 2009; 10:848-56. [PMID: 19597499 DOI: 10.1038/ni.1766] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2009] [Accepted: 06/08/2009] [Indexed: 11/17/2022]
Abstract
Themis (Thymocyte expressed molecule involved in selection), a member of a family of proteins with unknown functions, is highly conserved among vertebrates. Here we found that Themis is expressed in high amounts in thymocytes between the pre-T cell receptor (TCR) and positive selection checkpoints, and in low amounts in mature T cells. Themis-deficient thymocytes exhibit defective positive selection, which results in reduced numbers of mature thymocytes. Negative selection is also impaired in Themis-deficient mice. A higher percentage of Themis-deficient T cells exhibit CD4+CD25+Foxp3+ regulatory and CD62LloCD44hi memory phenotypes than in wild-type mice. Supporting a role for Themis in TCR signaling, this protein is phosphorylated quickly after TCR stimulation, and is needed for optimal TCR-driven Ca2+ mobilization and Erk activation.
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32
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Abstract
Recently implemented fluorescence imaging techniques, such as total internal reflection fluorescence microscopy and two-photon laser scanning microscopy, have made possible multiscale analysis of the immune response from single molecules in an interface to cells moving in lymphoid tissues and tumors. In this review, we consider components of T cell sensitivity: the immunological synapse, the coordination of migration, and antigen recognition in vivo. Potency, dose, and detection threshold for peptide-MHC determine T cell sensitivity. The immunological synapse incorporates T cell receptor microclusters that initiate and sustain signaling, and it also determines the positional stability of the T cells through symmetry and symmetry breaking. In vivo decisions by T cells on stopping or migration are based on antigen stop signals and environmental go signals that can sometimes prevent arrest of T cells altogether, and thus can change the outcome of antigen encounters.
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Affiliation(s)
- Michael L Dustin
- Department of Pathology, Program of Molecular Pathogenesis, Skirball Institute of BioMolecular Medicine, NYU School of Medicine, 540 First Avenue, New York, NY 10016, USA
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33
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Gascoigne NRJ, Ampudia J, Clamme JP, Fu G, Lotz C, Mallaun M, Niederberger N, Palmer E, Rybakin V, Yachi PP, Zal T. Visualizing intermolecular interactions in T cells. Curr Top Microbiol Immunol 2009; 334:31-46. [PMID: 19521680 PMCID: PMC3079427 DOI: 10.1007/978-3-540-93864-4_2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The use of appropriate fluorescent proteins has allowed the use of FRET microscopy for investigation of intermolecular interactions in living cells. This method has the advantage of both being dynamic and of working at the subcellular level, so that the time and place where proteins interact can be visualized. We have used FRET microscopy to analyze the interactions between the T cell antigen receptor and the coreceptors CD4 and CD8. This chapter reviews data on how these coreceptors are recruited to the immunological synapse, and how they interact when the T cell is stimulated by different ligands.
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Affiliation(s)
- Nicholas R J Gascoigne
- Department of Immunology and Microbial Science, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.
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34
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Mareeva T, Martinez-Hackert E, Sykulev Y. How a T cell receptor-like antibody recognizes major histocompatibility complex-bound peptide. J Biol Chem 2008; 283:29053-9. [PMID: 18703505 PMCID: PMC2570882 DOI: 10.1074/jbc.m804996200] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2008] [Revised: 07/30/2008] [Indexed: 11/06/2022] Open
Abstract
We determined the crystal structures of the T cell receptor (TCR)-like antibody 25-D1.16 Fab fragment bound to a complex of SIINFEKL peptide from ovalbumin and the H-2K(b) molecule. Remarkably, this antibody directly "reads" the structure of the major histocompatibility complex (MHC)-bound peptide, employing the canonical diagonal binding mode utilized by most TCRs. This is in marked contrast with another TCR-like antibody, Hyb3, bound to melanoma peptide MAGE-A1 in association with HLA-A1 MHC class I. Hyb3 assumes a non-canonical orientation over its cognate peptide-MHC and appears to recognize a conformational epitope in which the MHC contribution is dominant. We conclude that TCR-like antibodies can recognize MHC-bound peptide via two different mechanisms: one is similar to that exploited by the preponderance of TCRs and the other requires a non-canonical antibody orientation over the peptide-MHC complex.
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Affiliation(s)
- Tatiana Mareeva
- Department of Microbiology and Immunology and the Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA
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Segura JM, Guillaume P, Mark S, Dojcinovic D, Johannsen A, Bosshard G, Angelov G, Legler DF, Vogel H, Luescher IF. Increased mobility of major histocompatibility complex I-peptide complexes decreases the sensitivity of antigen recognition. J Biol Chem 2008; 283:24254-63. [PMID: 18579518 DOI: 10.1074/jbc.m803549200] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
CD8(+) cytotoxic T lymphocytes (CTL) can recognize and kill target cells expressing only a few cognate major histocompatibility complex (MHC) I-peptide complexes. This high sensitivity requires efficient scanning of a vast number of highly diverse MHC I-peptide complexes by the T cell receptor in the contact site of transient conjugates formed mainly by nonspecific interactions of ICAM-1 and LFA-1. Tracking of single H-2K(d) molecules loaded with fluorescent peptides on target cells and nascent conjugates with CTL showed dynamic transitions between states of free diffusion and immobility. The immobilizations were explained by association of MHC I-peptide complexes with ICAM-1 and strongly increased their local concentration in cell adhesion sites and hence their scanning by T cell receptor. In nascent immunological synapses cognate complexes became immobile, whereas noncognate ones diffused out again. Interfering with this mobility modulation-based concentration and sorting of MHC I-peptide complexes strongly impaired the sensitivity of antigen recognition by CTL, demonstrating that it constitutes a new basic aspect of antigen presentation by MHC I molecules.
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Affiliation(s)
- Jean-Manuel Segura
- Ludwig Institute for Cancer Research, Lausanne Branch, University of Lausanne, CH-1066 Epalinges, Switzerland
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