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Guo L, Shen S, Rowley JW, Tolley ND, Jia W, Manne BK, McComas KN, Bolingbroke B, Kosaka Y, Krauel K, Denorme F, Jacob SP, Eustes AS, Campbell RA, Middleton EA, He X, Brown SM, Morrell CN, Weyrich AS, Rondina MT. Platelet MHC class I mediates CD8+ T-cell suppression during sepsis. Blood 2021; 138:401-416. [PMID: 33895821 PMCID: PMC8343546 DOI: 10.1182/blood.2020008958] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 01/13/2021] [Indexed: 02/06/2023] Open
Abstract
Circulating platelets interact with leukocytes to modulate host immune and thrombotic responses. In sepsis, platelet-leukocyte interactions are increased and have been associated with adverse clinical events, including increased platelet-T-cell interactions. Sepsis is associated with reduced CD8+ T-cell numbers and functional responses, but whether platelets regulate CD8+ T-cell responses during sepsis remains unknown. In our current study, we systemically evaluated platelet antigen internalization and presentation through major histocompatibility complex class I (MHC-I) and their effects on antigen-specific CD8+ T cells in sepsis in vivo and ex vivo. We discovered that both human and murine platelets internalize and proteolyze exogenous antigens, generating peptides that are loaded onto MHC-I. The expression of platelet MHC-I, but not platelet MHC-II, is significantly increased in human and murine platelets during sepsis and in human megakaryocytes stimulated with agonists generated systemically during sepsis (eg, interferon-γ and lipopolysaccharide). Upregulation of platelet MHC-I during sepsis increases antigen cross-presentation and interactions with CD8+ T cells in an antigen-specific manner. Using a platelet lineage-specific MHC-I-deficient mouse strain (B2Mf/f-Pf4Cre), we demonstrate that platelet MHC-I regulates antigen-specific CD8+ T-cell proliferation in vitro, as well as the number and functional responses of CD8+ T cells in vivo, during sepsis. Loss of platelet MHC-I reduces sepsis-associated mortality in mice in an antigen-specific setting. These data identify a new mechanism by which platelets, through MHC-I, process and cross-present antigens, engage antigen-specific CD8+ T cells, and regulate CD8+ T-cell numbers, functional responses, and outcomes during sepsis.
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Affiliation(s)
- Li Guo
- Molecular Medicine Program, University of Utah, Salt Lake City, UT
| | - Sikui Shen
- Molecular Medicine Program, University of Utah, Salt Lake City, UT
- West China Hospital, Sichuan University, Chengdu, China
| | - Jesse W Rowley
- Molecular Medicine Program, University of Utah, Salt Lake City, UT
- Pulmonary and Critical Care Division, Department of Medicine, School of Medicine, University of Utah, Salt Lake City, UT
| | - Neal D Tolley
- Molecular Medicine Program, University of Utah, Salt Lake City, UT
| | - Wenwen Jia
- Molecular Medicine Program, University of Utah, Salt Lake City, UT
- Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu, China
| | | | - Kyra N McComas
- Molecular Medicine Program, University of Utah, Salt Lake City, UT
| | - Ben Bolingbroke
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT
| | - Yasuhiro Kosaka
- Molecular Medicine Program, University of Utah, Salt Lake City, UT
| | - Krystin Krauel
- Molecular Medicine Program, University of Utah, Salt Lake City, UT
- Department of Cardiology and Angiology I, Heart Center, University of Freiburg, Freiburg, Germany
| | - Frederik Denorme
- Molecular Medicine Program, University of Utah, Salt Lake City, UT
| | - Shancy P Jacob
- Molecular Medicine Program, University of Utah, Salt Lake City, UT
| | - Alicia S Eustes
- Molecular Medicine Program, University of Utah, Salt Lake City, UT
- Internal Medicine, University of Iowa, Iowa City, IA
| | - Robert A Campbell
- Molecular Medicine Program, University of Utah, Salt Lake City, UT
- Division of General Internal Medicine, Department of Medicine, School of Medicine, and
| | - Elizabeth A Middleton
- Molecular Medicine Program, University of Utah, Salt Lake City, UT
- Pulmonary and Critical Care Division, Department of Medicine, School of Medicine, University of Utah, Salt Lake City, UT
| | - Xiao He
- Department of Pathology, University of Utah, Salt Lake City, UT
| | - Samuel M Brown
- Pulmonary and Critical Care Division, Department of Medicine, School of Medicine, University of Utah, Salt Lake City, UT
- Center for Humanizing Critical Care, Intermountain Healthcare, Murray, UT
- Pulmonary and Critical Care Division, Department of Medicine, Intermountain Medical Center, Murray, UT
| | - Craig N Morrell
- Aab Cardiovascular Research Institute, University of Rochester Medical Center, Rochester, NY; and
| | - Andrew S Weyrich
- Molecular Medicine Program, University of Utah, Salt Lake City, UT
- Pulmonary and Critical Care Division, Department of Medicine, School of Medicine, University of Utah, Salt Lake City, UT
| | - Matthew T Rondina
- Molecular Medicine Program, University of Utah, Salt Lake City, UT
- Division of General Internal Medicine, Department of Medicine, School of Medicine, and
- Department of Pathology, University of Utah, Salt Lake City, UT
- Department of Internal Medicine, George E. Wahlen VA Medical Center and Geriatric Research Education Clinical Center (GRECC), Salt Lake City, UT
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2
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Sonntag K, Hashimoto H, Eyrich M, Menzel M, Schubach M, Döcker D, Battke F, Courage C, Lambertz H, Handgretinger R, Biskup S, Schilbach K. Immune monitoring and TCR sequencing of CD4 T cells in a long term responsive patient with metastasized pancreatic ductal carcinoma treated with individualized, neoepitope-derived multipeptide vaccines: a case report. J Transl Med 2018; 16:23. [PMID: 29409514 PMCID: PMC5801813 DOI: 10.1186/s12967-018-1382-1] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Accepted: 01/10/2018] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Cancer vaccines can effectively establish clinically relevant tumor immunity. Novel sequencing approaches rapidly identify the mutational fingerprint of tumors, thus allowing to generate personalized tumor vaccines within a few weeks from diagnosis. Here, we report the case of a 62-year-old patient receiving a four-peptide-vaccine targeting the two sole mutations of his pancreatic tumor, identified via exome sequencing. METHODS Vaccination started during chemotherapy in second complete remission and continued monthly thereafter. We tracked IFN-γ+ T cell responses against vaccine peptides in peripheral blood after 12, 17 and 34 vaccinations by analyzing T-cell receptor (TCR) repertoire diversity and epitope-binding regions of peptide-reactive T-cell lines and clones. By restricting analysis to sorted IFN-γ-producing T cells we could assure epitope-specificity, functionality, and TH1 polarization. RESULTS A peptide-specific T-cell response against three of the four vaccine peptides could be detected sequentially. Molecular TCR analysis revealed a broad vaccine-reactive TCR repertoire with clones of discernible specificity. Four identical or convergent TCR sequences could be identified at more than one time-point, indicating timely persistence of vaccine-reactive T cells. One dominant TCR expressing a dual TCRVα chain could be found in three T-cell clones. The observed T-cell responses possibly contributed to clinical outcome: The patient is alive 6 years after initial diagnosis and in complete remission for 4 years now. CONCLUSIONS Therapeutic vaccination with a neoantigen-derived four-peptide vaccine resulted in a diverse and long-lasting immune response against these targets which was associated with prolonged clinical remission. These data warrant confirmation in a larger proof-of concept clinical trial.
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Affiliation(s)
- Katja Sonntag
- Department of Pediatric Hematology and Oncology, University Children's Hospital Tübingen, Hoppe-Seyler Street 1, 72076, Tübingen, Germany
| | - Hisayoshi Hashimoto
- Department of Pediatric Hematology and Oncology, University Children's Hospital Tübingen, Hoppe-Seyler Street 1, 72076, Tübingen, Germany
| | - Matthias Eyrich
- Department of Pediatric Hematology, Oncology and Stem Cell Transplantation, University Medical Center Würzburg, Josef-Schneider Street 2, 97080, Würzburg, Germany
| | - Moritz Menzel
- Center for Genomics and Transcriptomics (CeGaT) GmbH and Practice for Human Genetics, Paul-Ehrlich-Straße 23, 72076, Tübingen, Germany
| | - Max Schubach
- Institute for Medical and Human Genetics, Charité - Universitätsmedizin Berlin, Augustenburger Platz 1, 13353, Berlin, Germany
| | - Dennis Döcker
- Center for Genomics and Transcriptomics (CeGaT) GmbH and Practice for Human Genetics, Paul-Ehrlich-Straße 23, 72076, Tübingen, Germany
| | - Florian Battke
- Center for Genomics and Transcriptomics (CeGaT) GmbH and Practice for Human Genetics, Paul-Ehrlich-Straße 23, 72076, Tübingen, Germany
| | - Carolina Courage
- Folkhälsan Institute of Genetics, Haartmaninkatu 8, 00014, Helsinki, Finland
| | - Helmut Lambertz
- Klinikum Garmisch-Partenkirchen GmbH, Zentrum für Innere Medizin, 82467, Garmisch-Partenkirchen, Germany
| | - Rupert Handgretinger
- Department of Pediatric Hematology and Oncology, University Children's Hospital Tübingen, Hoppe-Seyler Street 1, 72076, Tübingen, Germany
| | - Saskia Biskup
- Center for Genomics and Transcriptomics (CeGaT) GmbH and Practice for Human Genetics, Paul-Ehrlich-Straße 23, 72076, Tübingen, Germany
| | - Karin Schilbach
- Department of Pediatric Hematology and Oncology, University Children's Hospital Tübingen, Hoppe-Seyler Street 1, 72076, Tübingen, Germany. .,University Children's Hospital, University Medical Center Tübingen, Hoppe-Seyler-Street 1, 72076, Tübingen, Germany.
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3
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Eckle SBG, Rossjohn J, McCluskey J. Alloreactivity. Methods Mol Biol 2013; 1034:3-39. [PMID: 23775729 DOI: 10.1007/978-1-62703-493-7_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
Abstract
The alloimmune response between individuals genetically disparate for antigens encoded within the major histocompatibility complex (MHC) remains a substantial barrier to transplantation of solid organs, tissues, and hematopoietic stem cells. Alloreactivity has been an immunological paradox because of its apparent contradiction to the requirement of MHC restriction for the induction of normal T lymphocyte mediated immune responses. Through crystallographic analyses and experimental systems utilizing murine CD8(+) cytolytic T cell clones, major advances have been achieved in understanding the molecular and structural basis of T cell receptor recognition of MHC-peptide complexes and the basis of T cell mediated alloreactivity. These studies have further provided an explanation for the relatively high frequencies of alloreactive T cells compared to the frequencies of T cells for microbial derived antigens.
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Affiliation(s)
- Sidonia B G Eckle
- Department of Microbiology & Immunology, University of Melbourne, Parkville, VIC, Australia
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Abstract
This essay provides an analysis of the inadequacy of the current view of restrictive recognition of peptide by the T-cell antigen receptor. A competing model is developed, and the experimental evidence for the prevailing model is reinterpreted in the new framework. The goal is to contrast the two models with respect to their consistency, coverage of the data, explanatory power, and predictability.
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Affiliation(s)
- Melvin Cohn
- Conceptual Immunology Group, The Salk Institute For Biological Studies, La Jolla, CA 92037, USA.
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5
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Fortner KA, Lees RK, MacDonald HR, Budd RC. Fas (CD95/APO-1) limits the expansion of T lymphocytes in an environment of limited T-cell antigen receptor/MHC contacts. Int Immunol 2011; 23:75-88. [PMID: 21266499 DOI: 10.1093/intimm/dxq466] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Fas-deficient mice (Fas(lpr/lpr)) and humans have profoundly dysregulated T lymphocyte homeostasis, which manifests as an accumulation of CD4(+) and CD8(+) T cells as well as an unusual population of CD4(-)CD8(-)TCRαβ(+) T cells. To date, no unifying model has explained both the increased T-cell numbers and the origin of the CD4(-)CD8(-)TCRαβ(+) T cells. As Fas(lpr/lpr) mice raised in a germ-free environment still manifest lymphadenopathy, we considered that this process is primarily driven by recurrent low-avidity TCR signaling in response to self-peptide/MHC as occurs during homeostatic proliferation. In these studies, we developed two independent systems to decrease the number of self-peptide/MHC contacts. First, expression of MHC class I was reduced in OT-I TCR transgenic mice. Although OT-I Fas(lpr/lpr) mice did not develop lymphadenopathy characteristic of Fas(lpr/lpr) mice, in the absence of MHC class I, OT-I Fas(lpr/lpr) T cells accumulated as both CD8(+) and CD4(-)CD8(-) T cells. In the second system, re-expression of β(2)m limited to thymic cortical epithelial cells of Fas(lpr/lpr) β(2)m-deficient mice yielded a model in which polyclonal CD8(+) thymocytes entered a peripheral environment devoid of MHC class I. These mice accumulated significantly greater numbers of CD4(-)CD8(-)TCRαβ(+) T cells than conventional Fas(lpr/lpr) mice. Thus, Fas shapes the peripheral T-cell repertoire by regulating the survival of a subset of T cells proliferating in response to limited self-peptide/MHC contacts.
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Affiliation(s)
- Karen A Fortner
- Immunobiology Program, Department of Medicine, The University of Vermont College of Medicine, Burlington, VT 05405-0068, USA.
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6
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Chervin AS, Stone JD, Bowerman NA, Kranz DM. Cutting edge: inhibitory effects of CD4 and CD8 on T cell activation induced by high-affinity noncognate ligands. THE JOURNAL OF IMMUNOLOGY 2010; 183:7639-43. [PMID: 19923452 DOI: 10.4049/jimmunol.0901664] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
It has been proposed that MHC restriction during thymocyte selection is controlled by coreceptor (CD4 or CD8) sequestration of the signaling molecule Lck. We explored this model as a mechanism for preventing peripheral T cell activation due to non-MHC ligand cross-reactivities of TCRs. TCRs that have a range of affinities for a class I MHC ligand were transduced into a T cell hybridoma in the absence or presence of coreceptors. High and intermediate affinity TCRs (K(D) = 17 and 540 nM) did not require CD8 for T cell activity, but CD4 acted as a potent inhibitor of the intermediate affinity TCR. These and other findings support the view that even high-affinity TCR:ligand interactions can be influenced by coreceptor sequestration of Lck. Thus, CD4 and CD8 act as "coreceptor inhibitors" to maintain appropriate TCR-mediated MHC restriction in peripheral T cell activity.
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Affiliation(s)
- Adam S Chervin
- Department of Biochemistry, University of Illinois, Urbana, IL 61801, USA
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7
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Amedei A, Niccolai E, Della Bella C, Cianchi F, Trallori G, Benagiano M, Bencini L, Bernini M, Farsi M, Moretti R, Del Prete G, D'Elios MM. Characterization of tumor antigen peptide-specific T cells isolated from the neoplastic tissue of patients with gastric adenocarcinoma. Cancer Immunol Immunother 2009; 58:1819-30. [PMID: 19319530 PMCID: PMC11030125 DOI: 10.1007/s00262-009-0693-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2008] [Accepted: 03/04/2009] [Indexed: 12/17/2022]
Abstract
Gastric cancer is a significant cause of morbidity and mortality worldwide. Surgical resection remains the primary curative treatment for gastric adenocarcinoma, but the poor (15-35%) survival rate at 5 years has prompted many studies for new therapeutic strategies, such as specific immunotherapy. The aim of this study was to analyze the functional properties of the T cell response to different antigen peptides related to gastric cancer in patients with gastric adenocarcinoma. To this purpose, we have cloned and characterized tumor-infiltrating T cells (TILs) isolated from the neoplastic gastric tissue samples. A T cell response specific to different peptides of gastric cancer antigens tested was documented in 17 out of 20 patients, selected for their HLA-A02 and/or -A24 alleles. Most of the cancer peptide-specific TILs expressed a Th1/Tc1 profile and cytotoxic activity against target cells. The effector functions of cancer peptide-specific T cells obtained from the peripheral blood of the same patients were also studied. The majority of peripheral blood peptide-specific T cells also expressed the Th1/Tc1 functional profile. In conclusion, in most of the patients with gastric adenocarcinoma, a specific type-1 T cell response to gastric cancer antigens was detectable and would have the potential of hamper tumor cell growth. However, in order to get tumor cell killing in vivo, the activity and the number of cancer peptide-specific Th1/Tc1 cells probably need to be enhanced by vaccination with the appropriate cancer antigenic peptides or by injection of the autologus tumor peptide-specific T cells expanded in vitro.
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Affiliation(s)
- Amedeo Amedei
- Department of Internal Medicine, University of Florence, Viale Morgagni 85, 50134 Florence, Italy.
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8
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Bosco N, Kirberg J, Ceredig R, Agenès F. Peripheral T cells in the thymus: have they just lost their way or do they do something? Immunol Cell Biol 2009; 87:50-7. [DOI: 10.1038/icb.2008.83] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Nabil Bosco
- Developmental and Molecular Immunology Laboratory, Department of Biomedicine, University of Basel Basel Switzerland
| | - Jörg Kirberg
- Department of Biochemistry, University of Lausanne Epalinges Switzerland
| | - Rod Ceredig
- Developmental and Molecular Immunology Laboratory, Department of Biomedicine, University of Basel Basel Switzerland
| | - Fabien Agenès
- INSERM U743, Département de microbiologie et immunologie de l'Université de Montréal, CR‐CHUM Montréal Quebec Canada
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9
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Komaniwa S, Hayashi H, Kawamoto H, Sato SB, Ikawa T, Katsura Y, Udaka K. Lipid-mediated presentation of MHC class II molecules guides thymocytes to the CD4 lineage. Eur J Immunol 2008; 39:96-112. [DOI: 10.1002/eji.200838796] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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10
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Huseby ES, Kappler JW, Marrack P. Thymic selection stifles TCR reactivity with the main chain structure of MHC and forces interactions with the peptide side chains. Mol Immunol 2008; 45:599-606. [PMID: 17920446 DOI: 10.1016/j.molimm.2006.03.025] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2006] [Accepted: 03/17/2006] [Indexed: 10/22/2022]
Affiliation(s)
- Eric S Huseby
- Howard Hughes Medical Institute and Integrated Department of Immunology, National Jewish Medical and Research Center, Denver, Colorado 80206, United States.
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11
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Colf LA, Bankovich AJ, Hanick NA, Bowerman NA, Jones LL, Kranz DM, Garcia KC. How a single T cell receptor recognizes both self and foreign MHC. Cell 2007; 129:135-46. [PMID: 17418792 DOI: 10.1016/j.cell.2007.01.048] [Citation(s) in RCA: 194] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2006] [Revised: 01/01/2007] [Accepted: 01/19/2007] [Indexed: 11/27/2022]
Abstract
alphabeta T cell receptors (TCRs) can crossreact with both self- and foreign- major histocompatibility complex (MHC) proteins in an enigmatic phenomenon termed alloreactivity. Here we present the 2.35 A structure of the 2C TCR complexed with its foreign ligand H-2L(d)-QL9. Surprisingly, we find that this TCR utilizes a different strategy to engage the foreign pMHC in comparison to the manner in which it recognizes a self ligand H-2K(b)-dEV8. 2C engages both shared and polymorphic residues on L(d) and K(b), as well as the unrelated QL9 and dEV8 peptide antigens, in unique pair-wise contacts, resulting in greater structural complementarity with the L(d)-QL9 complex. In the structure of an engineered, high-affinity 2C TCR variant bound to H-2L(d)-QL9, the "wild-type" TCR-MHC binding orientation persists despite modified TCR-CDR3alpha interactions with peptide. Thus, a single TCR recognizes two globally similar, but distinct ligands by divergent mechanisms, indicating that receptor-ligand crossreactivity can occur in the absence of molecular mimicry.
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MESH Headings
- Amino Acid Sequence
- Autoantigens/chemistry
- Autoantigens/immunology
- Autoantigens/metabolism
- Complementarity Determining Regions/metabolism
- Crystallography, X-Ray
- H-2 Antigens/chemistry
- H-2 Antigens/immunology
- H-2 Antigens/metabolism
- Histocompatibility Antigen H-2D
- Isoantigens/chemistry
- Isoantigens/immunology
- Isoantigens/metabolism
- Ketoglutarate Dehydrogenase Complex/chemistry
- Ketoglutarate Dehydrogenase Complex/immunology
- Ligands
- Models, Molecular
- Molecular Sequence Data
- Peptides/chemistry
- Peptides/immunology
- Peptides/metabolism
- Protein Binding
- Receptors, Antigen, T-Cell, alpha-beta/chemistry
- Receptors, Antigen, T-Cell, alpha-beta/immunology
- Receptors, Antigen, T-Cell, alpha-beta/metabolism
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Affiliation(s)
- Leremy A Colf
- Howard Hughes Medical Institute, Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA
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12
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Leng Q, Ge Q, Nguyen T, Eisen HN, Chen J. Stage-dependent reactivity of thymocytes to self-peptide--MHC complexes. Proc Natl Acad Sci U S A 2007; 104:5038-43. [PMID: 17360333 PMCID: PMC1829260 DOI: 10.1073/pnas.0700674104] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In mice that express a transgene for the 2C T cell antigen-receptor (TCR) and lack a recombinase-activating gene (2C(+)RAG(-/-) mice) most of the peripheral T cells are CD8(+), a few are CD4(+), and a significant fraction are CD4(-)CD8(-) [double negative (DN)]. The DN 2C cells, like DN T cells that are abundant in various other alphabeta TCR-transgenic mice, appear to be derived directly from DN thymocytes that prematurely express the TCR transgene. The DN 2C cells are virtually absent in mice deficient in major histocompatibility complex class II (MHC-II) but more abundant in mice deficient in MHC-I, suggesting that the DN 2C thymocytes are positively selected by self-peptide-MHC-II (pMHC-II) complexes and negatively selected by self-pMHC-I complexes. The pMHC-I complexes, however, positively select CD8(+) 2C T cells in the same mice. The different effects of thymic pMHC-I on DN and CD8(+) thymocytes are consistent with the finding that DN 2C thymocytes are more sensitive than more mature CD4(+)CD8(+) [double positive (DP)] thymocytes to a weak pMHC-I agonist for the 2C TCR. Together with previous evidence that DP thymocytes respond more sensitively than T cells in the periphery to weak pMHC agonists, the findings suggest progressive decreases in responsiveness to self-pMHC-I complexes as thymocytes develop from DN to DP thymocytes and then to mature naïve T cells in the periphery.
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Affiliation(s)
- Qibin Leng
- Center for Cancer Research and Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Qing Ge
- Center for Cancer Research and Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Tam Nguyen
- Center for Cancer Research and Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139
| | | | - Jianzhu Chen
- *To whom correspondence may be addressed. E-mail: or
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