1
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Baldwin I, Robey EA. Adjusting to self in the thymus: CD4 versus CD8 lineage commitment and regulatory T cell development. J Exp Med 2024; 221:e20230896. [PMID: 38980291 PMCID: PMC11232887 DOI: 10.1084/jem.20230896] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2024] [Revised: 05/22/2024] [Accepted: 06/27/2024] [Indexed: 07/10/2024] Open
Abstract
During thymic development, thymocytes adjust their TCR response based on the strength of their reactivity to self-peptide MHC complexes. This tuning process allows thymocytes with a range of self-reactivities to survive positive selection and contribute to a diverse T cell pool. In this review, we will discuss recent advances in our understanding of how thymocytes tune their responsiveness during positive selection, and we present a "sequential selection" model to explain how MHC specificity influences lineage choice. We also discuss recent evidence for cell type diversity in the medulla and discuss how this heterogeneity may contribute to medullary niches for negative selection and regulatory T cell development.
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Affiliation(s)
- Isabel Baldwin
- Division of Immunology and Molecular Medicine, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Ellen A. Robey
- Division of Immunology and Molecular Medicine, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
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2
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Welsh RA, Song N, Park CS, Peske JD, Sadegh-Nasseri S. H2-O deficiency promotes regulatory T cell differentiation and CD4 T cell hyperactivity. Front Immunol 2024; 14:1304798. [PMID: 38250071 PMCID: PMC10796743 DOI: 10.3389/fimmu.2023.1304798] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Accepted: 12/11/2023] [Indexed: 01/23/2024] Open
Abstract
Regulatory T cells (Treg) are crucial immune modulators, yet the exact mechanism of thymic Treg development remains controversial. Here, we present the first direct evidence for H2-O, an MHC class II peptide editing molecular chaperon, on selection of thymic Tregs. We identified that lack of H2-O in the thymic medulla promotes thymic Treg development and leads to an increased peripheral Treg frequency. Single-cell RNA-sequencing (scRNA-seq) analysis of splenic CD4 T cells revealed not only an enrichment of effector-like Tregs, but also activated CD4 T cells in the absence of H2-O. Our data support two concepts; a) lack of H2-O expression in the thymic medulla creates an environment permissive to Treg development and, b) that loss of H2-O drives increased basal auto-stimulation of CD4 T cells. These findings can help in better understanding of predispositions to autoimmunity and design of therapeutics for treatment of autoimmune diseases.
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3
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Manoharan Valerio M, Arana K, Guan J, Chan SW, Yang X, Kurd N, Lee A, Shastri N, Coscoy L, Robey EA. The promiscuous development of an unconventional Qa1b-restricted T cell population. Front Immunol 2023; 14:1250316. [PMID: 38022509 PMCID: PMC10644506 DOI: 10.3389/fimmu.2023.1250316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Accepted: 10/06/2023] [Indexed: 12/01/2023] Open
Abstract
MHC-E restricted CD8 T cells show promise in vaccine settings, but their development and specificity remain poorly understood. Here we focus on a CD8 T cell population reactive to a self-peptide (FL9) bound to mouse MHC-E (Qa-1b) that is presented in response to loss of the MHC I processing enzyme ERAAP, termed QFL T cells. We find that mature QFL thymocytes are predominantly CD8αβ+CD4-, show signs of agonist selection, and give rise to both CD8αα and CD8αβ intraepithelial lymphocytes (IEL), as well as memory phenotype CD8αβ T cells. QFL T cells require the MHC I subunit β-2 microglobulin (β2m), but do not require Qa1b or classical MHC I for positive selection. However, QFL thymocytes do require Qa1b for agonist selection and full functionality. Our data highlight the relaxed requirements for positive selection of an MHC-E restricted T cell population and suggest a CD8αβ+CD4- pathway for development of CD8αα IELs.
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Affiliation(s)
- Michael Manoharan Valerio
- Division of Immunology and Molecular Medicine, Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA, United States
| | - Kathya Arana
- Division of Immunology and Molecular Medicine, Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA, United States
| | - Jian Guan
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Shiao Wei Chan
- Division of Immunology and Molecular Medicine, Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA, United States
| | - Xiaokun Yang
- Division of Immunology and Molecular Medicine, Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA, United States
| | - Nadia Kurd
- Division of Immunology and Molecular Medicine, Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA, United States
| | - Angus Lee
- Gene Targeting Facility Cancer Research Laboratory, University of California Berkeley, Berkeley, CA, United States
| | - Nilabh Shastri
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Laurent Coscoy
- Division of Immunology and Molecular Medicine, Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA, United States
| | - Ellen A. Robey
- Division of Immunology and Molecular Medicine, Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA, United States
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4
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Welsh RA, Song N, Park CS, Peske JD, Sadegh-Nasseri S. H2-O deficiency promotes regulatory T cell differentiation and CD4 T cell hyperactivity. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.14.553240. [PMID: 37645777 PMCID: PMC10462011 DOI: 10.1101/2023.08.14.553240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
Regulatory T cells (Treg) are crucial immune modulators, yet the exact mechanism of thymic Treg development remains controversial. Here, we present the first direct evidence for H2-O, an MHC class II peptide editing molecular chaperon, on selection of thymic Tregs. We provide evidence that lack of H2-O in the thymic medulla promotes thymic Treg development and leads to an increased peripheral Treg frequency. Single-cell RNA-sequencing (scRNA-seq) analysis of splenic CD4 T cells revealed not only of an enrichment of effector-like Tregs but also of activated CD4 T cells in the absence of H2-O. Our data support two concepts; a) lack of H2-O expression in the thymic medulla creates an environment permissive to Treg development and, b) that loss of H2-O drives increased basal auto-stimulation of CD4 T cells. These findings can help in better understanding of predispositions to autoimmunity and design of therapeutics for treatment of autoimmune diseases.
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5
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Funasaki S, Hatano A, Nakatsumi H, Koga D, Sugahara O, Yumimoto K, Baba M, Matsumoto M, Nakayama KI. A stepwise and digital pattern of RSK phosphorylation determines the outcome of thymic selection. iScience 2023; 26:107552. [PMID: 37646020 PMCID: PMC10460994 DOI: 10.1016/j.isci.2023.107552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 07/02/2023] [Accepted: 08/03/2023] [Indexed: 09/01/2023] Open
Abstract
Developing CD4+CD8+ double-positive (DP) thymocytes with randomly generated T cell receptors (TCRs) undergo positive (maturation) or negative (apoptosis) selection on the basis of the strength of TCR stimulation. Selection fate is determined by engagement of TCR ligands with a subtle difference in affinity, but the molecular details of TCR signaling leading to the different selection outcomes have remained unclear. We performed phosphoproteome analysis of DP thymocytes and found that p90 ribosomal protein kinase (RSK) phosphorylation at Thr562 was induced specifically by high-affinity peptide ligands. Such phosphorylation of RSK triggered its translocation to the nucleus, where it phosphorylated the nuclear receptor Nur77 and thereby promoted its mitochondrial translocation for apoptosis induction. Inhibition of RSK activity protected DP thymocytes from antigen-induced cell death. We propose that RSK phosphorylation constitutes a mechanism by which DP thymocytes generate a stepwise and binary signal in response to exposure to TCR ligands with a graded affinity.
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Affiliation(s)
- Shintaro Funasaki
- Department of Molecular and Cellular Biology, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Fukuoka 812-8582, Japan
- Laboratory of Cancer Metabolism, International Research Center for Medical Sciences (IRCMS), Kumamoto University, Kumamoto, Kumamoto 860-0811, Japan
| | - Atsushi Hatano
- Department of Omics and Systems Biology, Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Niigata 951-8510, Japan
| | - Hirokazu Nakatsumi
- Department of Molecular and Cellular Biology, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Fukuoka 812-8582, Japan
| | - Daisuke Koga
- Department of Molecular and Cellular Biology, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Fukuoka 812-8582, Japan
| | - Osamu Sugahara
- Department of Molecular and Cellular Biology, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Fukuoka 812-8582, Japan
| | - Kanae Yumimoto
- Department of Molecular and Cellular Biology, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Fukuoka 812-8582, Japan
| | - Masaya Baba
- Laboratory of Cancer Metabolism, International Research Center for Medical Sciences (IRCMS), Kumamoto University, Kumamoto, Kumamoto 860-0811, Japan
| | - Masaki Matsumoto
- Department of Molecular and Cellular Biology, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Fukuoka 812-8582, Japan
- Department of Omics and Systems Biology, Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Niigata 951-8510, Japan
| | - Keiichi I. Nakayama
- Department of Molecular and Cellular Biology, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Fukuoka 812-8582, Japan
- Anticancer Strategies Laboratory, TMDU Advanced Research Institute, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo 113-8510, Japan
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6
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Stadinski BD, Cleveland SB, Brehm MA, Greiner DL, Huseby PG, Huseby ES. I-A g7 β56/57 polymorphisms regulate non-cognate negative selection to CD4 + T cell orchestrators of type 1 diabetes. Nat Immunol 2023; 24:652-663. [PMID: 36807641 PMCID: PMC10623581 DOI: 10.1038/s41590-023-01441-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 01/20/2023] [Indexed: 02/22/2023]
Abstract
Genetic susceptibility to type 1 diabetes is associated with homozygous expression of major histocompatibility complex class II alleles that carry specific beta chain polymorphisms. Why heterozygous expression of these major histocompatibility complex class II alleles does not confer a similar predisposition is unresolved. Using a nonobese diabetic mouse model, here we show that heterozygous expression of the type 1 diabetes-protective allele I-Ag7 β56P/57D induces negative selection to the I-Ag7-restricted T cell repertoire, including beta-islet-specific CD4+ T cells. Surprisingly, negative selection occurs despite I-Ag7 β56P/57D having a reduced ability to present beta-islet antigens to CD4+ T cells. Peripheral manifestations of non-cognate negative selection include a near complete loss of beta-islet-specific CXCR6+ CD4+ T cells, an inability to cross-prime islet-specific glucose-6-phosphatase catalytic subunit-related protein and insulin-specific CD8+ T cells and disease arrest at the insulitis stage. These data reveal that negative selection on non-cognate self-antigens in the thymus can promote T cell tolerance and protection from autoimmunity.
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Affiliation(s)
- Brian D Stadinski
- Department of Pathology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Sarah B Cleveland
- Department of Pathology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Michael A Brehm
- Department of Molecular Medicine, Diabetes Center of Excellence, University of Massachusetts Medical School, Worcester, MA, USA
| | - Dale L Greiner
- Department of Molecular Medicine, Diabetes Center of Excellence, University of Massachusetts Medical School, Worcester, MA, USA
| | - Priya G Huseby
- Department of Pathology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Eric S Huseby
- Department of Pathology, University of Massachusetts Medical School, Worcester, MA, USA.
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7
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Teixeiro E, Daniels MA. Fetal Thymic Organ Culture and Negative Selection. Methods Mol Biol 2023; 2580:293-302. [PMID: 36374465 DOI: 10.1007/978-1-0716-2740-2_18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Negative selection removes potentially harmful T cell precursors from the conventional T cell pool. This process can involve the induction of apoptosis, anergy, receptor editing, or deviation into a regulatory T cell lineage. As such, this process is essential for the health of an organism through its contribution to central and peripheral tolerance. While a great deal is known about the process, the precise mechanisms that regulate these various forms of negative selection are not clear. Numerous models exist with the potential to address these questions in vitro and in vivo. This chapter describes fetal thymic organ culture methods designed to analyze the signals that determine these unique cell fates.
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Affiliation(s)
- Emma Teixeiro
- Department of Molecular Microbiology and Immunology, NextGen Precision Health, University of Missouri, Columbia, MO, USA
| | - Mark A Daniels
- Department of Molecular Microbiology and Immunology, NextGen Precision Health, University of Missouri, Columbia, MO, USA.
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8
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Huseby ES, Teixeiro E. The perception and response of T cells to a changing environment are based on the law of initial value. Sci Signal 2022; 15:eabj9842. [PMID: 35639856 PMCID: PMC9290192 DOI: 10.1126/scisignal.abj9842] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
αβ T cells are critical components of the adaptive immune system and are capable of inducing sterilizing immunity after pathogen infection and eliminating transformed tumor cells. The development and function of T cells are controlled through the T cell antigen receptor, which recognizes peptides displayed on major histocompatibility complex (MHC) molecules. Here, we review how T cells generate the ability to recognize self-peptide-bound MHC molecules and use signals derived from these interactions to instruct cellular development, activation thresholds, and functional specialization in the steady state and during immune responses. We argue that the basic tenants of T cell development and function follow Weber-Fetcher's law of just noticeable differences and Wilder's law of initial value. Together, these laws argue that the ability of a system to respond and the quality of that response are scalable to the basal state of that system. Manifestation of these laws in T cells generates clone-specific activation thresholds that are based on perceivable differences between homeostasis and pathogen encounter (self versus nonself discrimination), as well as poised states for subsequent differentiation into specific effector cell lineages.
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Affiliation(s)
- Eric S. Huseby
- Department of Pathology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Emma Teixeiro
- Department of Molecular Microbiology and Immunology, School of Medicine, University of Missouri, Columbia, MO 65212, USA
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9
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Wong HS, Germain RN. Mesoscale T cell antigen discrimination emerges from intercellular feedback. Trends Immunol 2021; 42:865-875. [PMID: 34493455 DOI: 10.1016/j.it.2021.08.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 08/13/2021] [Accepted: 08/13/2021] [Indexed: 12/14/2022]
Abstract
Mature T cells must distinguish between foreign and self-antigens to promote host defense while limiting autoimmunity. How such discrimination occurs reproducibly has been explored extensively regarding mechanisms regulating initial T cell activation at short time and length scales. Here, we suggest that T cells encounter a higher-level discriminatory boundary post-activation, empowering or constraining their responses over greater spatiotemporal scales. This boundary emerges from coordinated communication among at least three cell types, forming a control system governed by intercellular circuits, including negative feedback from regulatory T cells (Tregs). We propose that the nonlinearities inherent to this system can amplify subtle baseline imbalances in a single cell type's functional state, altering the threshold for productive T cell responses and autoimmune disease risk.
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Affiliation(s)
- Harikesh S Wong
- Lymphocyte Biology Section, Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892-1892, USA.
| | - Ronald N Germain
- Lymphocyte Biology Section, Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892-1892, USA.
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10
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Zareie P, Szeto C, Farenc C, Gunasinghe SD, Kolawole EM, Nguyen A, Blyth C, Sng XYX, Li J, Jones CM, Fulcher AJ, Jacobs JR, Wei Q, Wojciech L, Petersen J, Gascoigne NRJ, Evavold BD, Gaus K, Gras S, Rossjohn J, La Gruta NL. Canonical T cell receptor docking on peptide-MHC is essential for T cell signaling. Science 2021; 372:372/6546/eabe9124. [PMID: 34083463 DOI: 10.1126/science.abe9124] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Accepted: 04/23/2021] [Indexed: 12/23/2022]
Abstract
T cell receptor (TCR) recognition of peptide-major histocompatibility complexes (pMHCs) is characterized by a highly conserved docking polarity. Whether this polarity is driven by recognition or signaling constraints remains unclear. Using "reversed-docking" TCRβ-variable (TRBV) 17+ TCRs from the naïve mouse CD8+ T cell repertoire that recognizes the H-2Db-NP366 epitope, we demonstrate that their inability to support T cell activation and in vivo recruitment is a direct consequence of reversed docking polarity and not TCR-pMHCI binding or clustering characteristics. Canonical TCR-pMHCI docking optimally localizes CD8/Lck to the CD3 complex, which is prevented by reversed TCR-pMHCI polarity. The requirement for canonical docking was circumvented by dissociating Lck from CD8. Thus, the consensus TCR-pMHC docking topology is mandated by T cell signaling constraints.
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Affiliation(s)
- Pirooz Zareie
- Infection and Immunity Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Christopher Szeto
- Infection and Immunity Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Carine Farenc
- Infection and Immunity Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Sachith D Gunasinghe
- European Molecular Biology Laboratory (EMBL) Australia Node in Single Molecule Science and the ARC Centre of Excellence in Advanced Molecular Imaging, School of Medical Sciences, University of New South Wales, New South Wales, Australia
| | - Elizabeth M Kolawole
- Department of Pathology, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Angela Nguyen
- Infection and Immunity Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Chantelle Blyth
- Infection and Immunity Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Xavier Y X Sng
- Infection and Immunity Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Jasmine Li
- Infection and Immunity Program and Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Claerwen M Jones
- Infection and Immunity Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Alex J Fulcher
- Monash Micro Imaging, Monash University, Clayton, Victoria, Australia
| | - Jesica R Jacobs
- Department of Pathology, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Qianru Wei
- Immunology Translational Research Programme and Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117545
| | - Lukasz Wojciech
- Immunology Translational Research Programme and Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117545
| | - Jan Petersen
- Infection and Immunity Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia.,Australian Research Council Centre of Excellence in Advanced Molecular Imaging, Monash University, Clayton, Victoria, Australia
| | - Nicholas R J Gascoigne
- Immunology Translational Research Programme and Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117545
| | - Brian D Evavold
- Department of Pathology, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Katharina Gaus
- European Molecular Biology Laboratory (EMBL) Australia Node in Single Molecule Science and the ARC Centre of Excellence in Advanced Molecular Imaging, School of Medical Sciences, University of New South Wales, New South Wales, Australia
| | - Stephanie Gras
- Infection and Immunity Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia. .,Australian Research Council Centre of Excellence in Advanced Molecular Imaging, Monash University, Clayton, Victoria, Australia
| | - Jamie Rossjohn
- Infection and Immunity Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia. .,Australian Research Council Centre of Excellence in Advanced Molecular Imaging, Monash University, Clayton, Victoria, Australia.,Institute of Infection and Immunity, Cardiff University School of Medicine, Heath Park, Cardiff, UK
| | - Nicole L La Gruta
- Infection and Immunity Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia.
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11
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Lutes LK, Steier Z, McIntyre LL, Pandey S, Kaminski J, Hoover AR, Ariotti S, Streets A, Yosef N, Robey EA. T cell self-reactivity during thymic development dictates the timing of positive selection. eLife 2021; 10:e65435. [PMID: 33884954 PMCID: PMC8116051 DOI: 10.7554/elife.65435] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Accepted: 04/21/2021] [Indexed: 12/14/2022] Open
Abstract
Functional tuning of T cells based on their degree of self-reactivity is established during positive selection in the thymus, although how positive selection differs for thymocytes with relatively low versus high self-reactivity is unclear. In addition, preselection thymocytes are highly sensitive to low-affinity ligands, but the mechanism underlying their enhanced T cell receptor (TCR) sensitivity is not fully understood. Here we show that murine thymocytes with low self-reactivity experience briefer TCR signals and complete positive selection more slowly than those with high self-reactivity. Additionally, we provide evidence that cells with low self-reactivity retain a preselection gene expression signature as they mature, including genes previously implicated in modulating TCR sensitivity and a novel group of ion channel genes. Our results imply that thymocytes with low self-reactivity downregulate TCR sensitivity more slowly during positive selection, and associate membrane ion channel expression with thymocyte self-reactivity and progress through positive selection.
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Affiliation(s)
- Lydia K Lutes
- Division of Immunology and Pathogenesis, Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
| | - Zoë Steier
- Department of Bioengineering, University of California, BerkeleyBerkeleyUnited States
| | - Laura L McIntyre
- Division of Immunology and Pathogenesis, Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
| | - Shraddha Pandey
- Division of Immunology and Pathogenesis, Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
| | - James Kaminski
- Center for Computational Biology, University of California, BerkeleyBerkeleyUnited States
| | - Ashley R Hoover
- Division of Immunology and Pathogenesis, Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
| | - Silvia Ariotti
- Division of Immunology and Pathogenesis, Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
| | - Aaron Streets
- Department of Bioengineering, University of California, BerkeleyBerkeleyUnited States
- Center for Computational Biology, University of California, BerkeleyBerkeleyUnited States
- Chan Zuckerberg BiohubSan FranciscoUnited States
| | - Nir Yosef
- Department of Bioengineering, University of California, BerkeleyBerkeleyUnited States
- Center for Computational Biology, University of California, BerkeleyBerkeleyUnited States
- Chan Zuckerberg BiohubSan FranciscoUnited States
- Department of Electrical Engineering and Computer Sciences, University of California, BerkeleyBerkeleyUnited States
- Ragon Institute of MGH, MIT and HarvardCambridgeUnited States
| | - Ellen A Robey
- Division of Immunology and Pathogenesis, Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
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12
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Li Y, Li K, Zhu L, Li B, Zong D, Cai P, Jiang C, Du P, Lin J, Qu K. Development of double-positive thymocytes at single-cell resolution. Genome Med 2021; 13:49. [PMID: 33771202 PMCID: PMC8004397 DOI: 10.1186/s13073-021-00861-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Accepted: 02/25/2021] [Indexed: 12/03/2022] Open
Abstract
BACKGROUND T cells generated from thymopoiesis are essential for the immune system, and recent single-cell studies have contributed to our understanding of the development of thymocytes at the genetic and epigenetic levels. However, the development of double-positive (DP) T cells, which comprise the majority of thymocytes, has not been well investigated. METHODS We applied single-cell sequencing to mouse thymocytes and analyzed the transcriptome data using Seurat. By applying unsupervised clustering, we defined thymocyte subtypes and validated DP cell subtypes by flow cytometry. We classified the cell cycle phases of each cell according to expression of cell cycle phase-specific genes. For immune synapse detection, we used immunofluorescent staining and ImageStream-based flow cytometry. We studied and integrated human thymocyte data to verify the conservation of our findings and also performed cross-species comparisons to examine species-specific gene regulation. RESULTS We classified blast, rearrangement, and selection subtypes of DP thymocytes and used the surface markers CD2 and Ly6d to identify these subtypes by flow cytometry. Based on this new classification, we found that the proliferation of blast DP cells is quite different from that of double-positive cells and other cell types, which tend to exit the cell cycle after a single round. At the DP cell selection stage, we observed that CD8-associated immune synapses formed between thymocytes, indicating that CD8sp selection occurred among thymocytes themselves. Moreover, cross-species comparison revealed species-specific transcription factors (TFs) that contribute to the transcriptional differences of thymocytes from humans and mice. CONCLUSIONS Our study classified DP thymocyte subtypes of different developmental stages and provided new insight into the development of DP thymocytes at single-cell resolution, furthering our knowledge of the fundamental immunological process of thymopoiesis.
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Affiliation(s)
- Young Li
- Department of oncology, The First Affiliated Hospital of USTC, Division of Molecular Medicine, Hefei National Laboratory for Physical Sciences at Microscale, School of Basic Medicine, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230021, Anhui, China
| | - Kun Li
- Department of oncology, The First Affiliated Hospital of USTC, Division of Molecular Medicine, Hefei National Laboratory for Physical Sciences at Microscale, School of Basic Medicine, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230021, Anhui, China
| | - Lianbang Zhu
- Department of oncology, The First Affiliated Hospital of USTC, Division of Molecular Medicine, Hefei National Laboratory for Physical Sciences at Microscale, School of Basic Medicine, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230021, Anhui, China
| | - Bin Li
- Department of oncology, The First Affiliated Hospital of USTC, Division of Molecular Medicine, Hefei National Laboratory for Physical Sciences at Microscale, School of Basic Medicine, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230021, Anhui, China
| | - Dandan Zong
- Department of oncology, The First Affiliated Hospital of USTC, Division of Molecular Medicine, Hefei National Laboratory for Physical Sciences at Microscale, School of Basic Medicine, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230021, Anhui, China
| | - Pengfei Cai
- Department of oncology, The First Affiliated Hospital of USTC, Division of Molecular Medicine, Hefei National Laboratory for Physical Sciences at Microscale, School of Basic Medicine, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230021, Anhui, China
| | - Chen Jiang
- Department of oncology, The First Affiliated Hospital of USTC, Division of Molecular Medicine, Hefei National Laboratory for Physical Sciences at Microscale, School of Basic Medicine, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230021, Anhui, China
| | - Pengcheng Du
- Department of oncology, The First Affiliated Hospital of USTC, Division of Molecular Medicine, Hefei National Laboratory for Physical Sciences at Microscale, School of Basic Medicine, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230021, Anhui, China
| | - Jun Lin
- Department of oncology, The First Affiliated Hospital of USTC, Division of Molecular Medicine, Hefei National Laboratory for Physical Sciences at Microscale, School of Basic Medicine, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230021, Anhui, China
| | - Kun Qu
- Department of oncology, The First Affiliated Hospital of USTC, Division of Molecular Medicine, Hefei National Laboratory for Physical Sciences at Microscale, School of Basic Medicine, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230021, Anhui, China.
- The CAS Key Laboratory of Innate Immunity and Chronic Disease, CAS Center for Excellence in Molecular Cell Sciences, University of Science and Technology of China, Hefei, 230021, Anhui, China.
- School of Data Science, University of Science and Technology of China, Hefei, 230027, Anhui, China.
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13
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Horkova V, Drobek A, Mueller D, Gubser C, Niederlova V, Wyss L, King CG, Zehn D, Stepanek O. Dynamics of the Coreceptor-LCK Interactions during T Cell Development Shape the Self-Reactivity of Peripheral CD4 and CD8 T Cells. Cell Rep 2021; 30:1504-1514.e7. [PMID: 32023465 PMCID: PMC7003063 DOI: 10.1016/j.celrep.2020.01.008] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Revised: 05/31/2019] [Accepted: 01/02/2020] [Indexed: 02/07/2023] Open
Abstract
Overtly self-reactive T cells are removed during thymic selection. However, it has been recently established that T cell self-reactivity promotes protective immune responses. Apparently, the level of self-reactivity of mature T cells must be tightly balanced. Our mathematical model and experimental data show that the dynamic regulation of CD4- and CD8-LCK coupling establish the self-reactivity of the peripheral T cell pool. The stoichiometry of the interaction between CD8 and LCK, but not between CD4 and LCK, substantially increases upon T cell maturation. As a result, peripheral CD8+ T cells are more self-reactive than CD4+ T cells. The different levels of self-reactivity of mature CD8+ and CD4+ T cells likely reflect the unique roles of these subsets in immunity. These results indicate that the evolutionary selection pressure tuned the CD4-LCK and CD8-LCK stoichiometries, as they represent the unique parts of the proximal T cell receptor (TCR) signaling pathway, which differ between CD4+ and CD8+ T cells. Coupling of CD8-LCK but not CD4-LCK increases upon T cell maturation Dynamics of coreceptor-LCK coupling stoichiometry establish T cell self-reactivity CD8+ T cells are more self-reactive than CD4+ T cells
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Affiliation(s)
- Veronika Horkova
- Laboratory of Adaptive Immunity, Institute of Molecular Genetics of the Czech Academy of Sciences, 14220 Prague, Czech Republic
| | - Ales Drobek
- Laboratory of Adaptive Immunity, Institute of Molecular Genetics of the Czech Academy of Sciences, 14220 Prague, Czech Republic
| | - Daniel Mueller
- Department of Biomedicine, University Hospital and University of Basel, 4031 Basel, Switzerland
| | - Celine Gubser
- Department of Biomedicine, University Hospital and University of Basel, 4031 Basel, Switzerland; Peter Doherty Institute, University of Melbourne, Melbourne, Australia
| | - Veronika Niederlova
- Laboratory of Adaptive Immunity, Institute of Molecular Genetics of the Czech Academy of Sciences, 14220 Prague, Czech Republic
| | - Lena Wyss
- Department of Biomedicine, University Hospital and University of Basel, 4031 Basel, Switzerland; Institute for Immunology, Biomedical Center (BMC) Munich, Ludwig-Maximilians-University, Munich, Germany
| | - Carolyn G King
- Department of Biomedicine, University Hospital and University of Basel, 4031 Basel, Switzerland
| | - Dietmar Zehn
- Division of Animal Physiology and Immunology, School of Life Sciences Weihenstephan, Technical University of Munich, Freising, Germany
| | - Ondrej Stepanek
- Laboratory of Adaptive Immunity, Institute of Molecular Genetics of the Czech Academy of Sciences, 14220 Prague, Czech Republic.
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14
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Abstract
The repertoire of αβ T cell antigen receptors (TCRs) on mature T cells is selected in the thymus where it is rendered both self-tolerant and restricted to the recognition of major histocompatibility complex molecules presenting peptide antigens (pMHC). It remains unclear whether germline TCR sequences exhibit an inherent bias to interact with pMHC prior to selection. Here, we isolated TCR libraries from unselected thymocytes and upon reexpression of these random TCR repertoires in recipient T cell hybridomas, interrogated their reactivities to antigen-presenting cell lines. While these random TCR combinations could potentially have reacted with any surface molecule on the cell lines, the hybridomas were stimulated most frequently by pMHC ligands. The nature and CDR3 loop composition of the TCRβ chain played a dominant role in determining pMHC-reactivity. Replacing the germline regions of mouse TCRβ chains with those of other jawed vertebrates preserved reactivity to mouse pMHC. Finally, introducing the CD4 coreceptor into the hybridomas increased the proportion of cells that could respond to pMHC ligands. Thus, αβ TCRs display an intrinsic and evolutionary conserved bias for pMHC molecules in the absence of any selective pressure, which is further strengthened in the presence of coreceptors.
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15
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Tischer DK, Weiner OD. Light-based tuning of ligand half-life supports kinetic proofreading model of T cell signaling. eLife 2019; 8:42498. [PMID: 30947808 PMCID: PMC6488292 DOI: 10.7554/elife.42498] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Accepted: 04/03/2019] [Indexed: 11/30/2022] Open
Abstract
T cells are thought to discriminate self from foreign peptides by converting small differences in ligand binding half-life into large changes in cell signaling. Such a kinetic proofreading model has been difficult to test directly, as existing methods of altering ligand binding half-life also change other potentially important biophysical parameters, most notably the mechanical stability of the receptor-ligand interaction. Here we develop an optogenetic approach to specifically tune the binding half-life of a chimeric antigen receptor without changing other binding parameters and provide direct evidence of kinetic proofreading in T cell signaling. This half-life discrimination is executed in the proximal signaling pathway, downstream of ZAP70 recruitment and upstream of diacylglycerol accumulation. Our methods represent a general tool for temporal and spatial control of T cell signaling and extend the reach of optogenetics to probe pathways where the individual molecular kinetics, rather than the ensemble average, gates downstream signaling.
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Affiliation(s)
- Doug K Tischer
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, United States.,Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, United States
| | - Orion David Weiner
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, United States
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16
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Yousefi OS, Günther M, Hörner M, Chalupsky J, Wess M, Brandl SM, Smith RW, Fleck C, Kunkel T, Zurbriggen MD, Höfer T, Weber W, Schamel WW. Optogenetic control shows that kinetic proofreading regulates the activity of the T cell receptor. eLife 2019; 8:42475. [PMID: 30947807 PMCID: PMC6488296 DOI: 10.7554/elife.42475] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Accepted: 03/05/2019] [Indexed: 12/18/2022] Open
Abstract
The immune system distinguishes between self and foreign antigens. The kinetic proofreading (KPR) model proposes that T cells discriminate self from foreign ligands by the different ligand binding half-lives to the T cell receptor (TCR). It is challenging to test KPR as the available experimental systems fall short of only altering the binding half-lives and keeping other parameters of the interaction unchanged. We engineered an optogenetic system using the plant photoreceptor phytochrome B (PhyB) as a ligand to selectively control the dynamics of ligand binding to the TCR by light. This opto-ligand-TCR system was combined with the unique property of PhyB to continuously cycle between the binding and non-binding states under red light, with the light intensity determining the cycling rate and thus the binding duration. Mathematical modeling of our experimental datasets showed that indeed the ligand-TCR interaction half-life is the decisive factor for activating downstream TCR signaling, substantiating KPR.
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Affiliation(s)
- O Sascha Yousefi
- Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany.,Faculty of Biology, University of Freiburg, Freiburg, Germany.,Spemann Graduate School of Biology and Medicine, University of Freiburg, Freiburg, Germany
| | - Matthias Günther
- Division of Theoretical Systems Biology, German Cancer Research Center, Heidelberg, Germany.,BioQuant Center, University of Heidelberg, Heidelberg, Germany
| | - Maximilian Hörner
- Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany.,Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Julia Chalupsky
- Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany.,Faculty of Biology, University of Freiburg, Freiburg, Germany.,Center for Chronic Immunodeficiency, Medical Center Freiburg and Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Maximilian Wess
- Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany.,Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Simon M Brandl
- Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany.,Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Robert W Smith
- Laboratory of Systems and Synthetic Biology, Wageningen University and Research, Wageningen, Netherlands
| | - Christian Fleck
- Laboratory of Systems and Synthetic Biology, Wageningen University and Research, Wageningen, Netherlands
| | - Tim Kunkel
- Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Matias D Zurbriggen
- Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany.,Faculty of Biology, University of Freiburg, Freiburg, Germany.,Institute of Synthetic Biology and Cluster of Excellence on Plant Sciences, University of Düsseldorf, Düsseldorf, Germany
| | - Thomas Höfer
- Division of Theoretical Systems Biology, German Cancer Research Center, Heidelberg, Germany.,BioQuant Center, University of Heidelberg, Heidelberg, Germany
| | - Wilfried Weber
- Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany.,Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Wolfgang Wa Schamel
- Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany.,Faculty of Biology, University of Freiburg, Freiburg, Germany.,Laboratory of Systems and Synthetic Biology, Wageningen University and Research, Wageningen, Netherlands
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17
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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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18
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Moro-García MA, Mayo JC, Sainz RM, Alonso-Arias R. Influence of Inflammation in the Process of T Lymphocyte Differentiation: Proliferative, Metabolic, and Oxidative Changes. Front Immunol 2018; 9:339. [PMID: 29545794 PMCID: PMC5839096 DOI: 10.3389/fimmu.2018.00339] [Citation(s) in RCA: 114] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Accepted: 02/06/2018] [Indexed: 01/02/2023] Open
Abstract
T lymphocytes, from their first encounter with their specific antigen as naïve cell until the last stages of their differentiation, in a replicative state of senescence, go through a series of phases. In several of these stages, T lymphocytes are subjected to exponential growth in successive encounters with the same antigen. This entire process occurs throughout the life of a human individual and, earlier, in patients with chronic infections/pathologies through inflammatory mediators, first acutely and later in a chronic form. This process plays a fundamental role in amplifying the activating signals on T lymphocytes and directing their clonal proliferation. The mechanisms that control cell growth are high levels of telomerase activity and maintenance of telomeric length that are far superior to other cell types, as well as metabolic adaptation and redox control. Large numbers of highly differentiated memory cells are accumulated in the immunological niches where they will contribute in a significant way to increase the levels of inflammatory mediators that will perpetuate the new state at the systemic level. These levels of inflammation greatly influence the process of T lymphocyte differentiation from naïve T lymphocyte, even before, until the arrival of exhaustion or cell death. The changes observed during lymphocyte differentiation are correlated with changes in cellular metabolism and these in turn are influenced by the inflammatory state of the environment where the cell is located. Reactive oxygen species (ROS) exert a dual action in the population of T lymphocytes. Exposure to high levels of ROS decreases the capacity of activation and T lymphocyte proliferation; however, intermediate levels of oxidation are necessary for the lymphocyte activation, differentiation, and effector functions. In conclusion, we can affirm that the inflammatory levels in the environment greatly influence the differentiation and activity of T lymphocyte populations. However, little is known about the mechanisms involved in these processes. The elucidation of these mechanisms would be of great help in the advance of improvements in pathologies with a large inflammatory base such as rheumatoid arthritis, intestinal inflammatory diseases, several infectious diseases and even, cancerous processes.
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Affiliation(s)
- Marco A Moro-García
- Department of Immunology, Hospital Universitario Central de Asturias (HUCA), Oviedo, Spain
| | - Juan C Mayo
- Department of Morphology and Cell Biology, Institute of Oncology of Asturias (IUOPA), University of Oviedo, Oviedo, Spain
| | - Rosa M Sainz
- Department of Morphology and Cell Biology, Institute of Oncology of Asturias (IUOPA), University of Oviedo, Oviedo, Spain
| | - Rebeca Alonso-Arias
- Department of Immunology, Hospital Universitario Central de Asturias (HUCA), Oviedo, Spain.,Facultad de Ciencias de la Salud, Universidad Autónoma de Chile, Talca, Chile
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19
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Choi S, Cornall R, Lesourne R, Love PE. THEMIS: Two Models, Different Thresholds. Trends Immunol 2017; 38:622-632. [PMID: 28697966 DOI: 10.1016/j.it.2017.06.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Revised: 06/13/2017] [Accepted: 06/14/2017] [Indexed: 11/17/2022]
Abstract
THEMIS, a recently identified T-lineage-restricted protein, is the founding member of a large metazoan protein family. Gene inactivation studies have revealed a critical requirement for THEMIS during thymocyte positive selection, implicating THEMIS in signaling downstream of the T cell antigen receptor (TCR), but the mechanistic underpinnings of THEMIS function have remained elusive. A previous model posited that THEMIS prevents thymocytes from inappropriately crossing the positive/negative selection threshold by dampening TCR signaling. However, new data suggest an alternative model where THEMIS enhances TCR signaling enabling thymocytes to reach the threshold for positive selection, avoiding death by neglect. We review the data supporting each model and conclude that the preponderance of evidence favors an enhancing function for THEMIS in TCR signaling.
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Affiliation(s)
- Seeyoung Choi
- Section on Hematopoiesis and Lymphocyte Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Richard Cornall
- MRC Human Immunology Unit, Weatherall Institute for Molecular Medicine, Nuffield Department of Medicine, University of Oxford, Oxford OX3 9DS, UK
| | - Renaud Lesourne
- Centre de Physiopathologie de Toulouse Purpan, Toulouse, France; Institut National de la Santé et de la Recherche Médicale, U1043, Centre National de la Recherche Scientifique, U5282, and Université de Toulouse, Université Paul Sabatier, Toulouse F-31300, France
| | - Paul E Love
- Section on Hematopoiesis and Lymphocyte Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
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20
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Abstract
The ability of T cells to respond to a wide array of foreign antigens while avoiding reactivity to self is largely determined by cellular selection of developing T cells in the thymus. While a great deal is known about the cell types and molecules involved in T-cell selection in the thymus, our understanding of the spatial and temporal aspects of this process remain relatively poorly understood. Thymocytes are highly motile within the thymus and travel between specialized microenvironments at different phases of their development while interacting with distinct sets of self-peptides and peptide presenting cells. A knowledge of when, where, and how thymocytes encounter self-peptide MHC ligands at different stages of thymic development is key to understanding T-cell selection. In the past several years, our laboratory has investigated this topic using two-photon time-lapse microscopy to directly visualize thymocyte migration and signaling events, together with a living thymic slice preparation to provide a synchronized experimental model of T-cell selection in situ. Here, we discuss recent advances in our understanding of the temporal and spatial aspects of T-cell selection, highlighting our own work, and placing them in the context of work from other groups.
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Affiliation(s)
- Nadia Kurd
- Division of Immunology and Pathogenesis, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, 94720, USA
| | - Ellen A Robey
- Division of Immunology and Pathogenesis, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, 94720, USA
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21
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Singh NJ. Self-reactivity as the necessary cost of maintaining a diverse memory T-cell repertoire. Pathog Dis 2016; 74:ftw092. [PMID: 27620200 DOI: 10.1093/femspd/ftw092] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/04/2016] [Indexed: 12/30/2022] Open
Abstract
The adaptive immune system is expected to protect the host from infectious agents and malignancies, while avoiding robust activation against self-peptides. However, T cells are notoriously inept at protection whenever the pathogen or tumor is persistent in the body for longer periods of time. While this has been thought of as an adaptation to limit the immunopathology from continued effector T-cell responses, it is also likely an extension of the T cell's intrinsic mechanisms which evolved to tolerate self-peptides. Here we deliberate on how the need to tolerate self-peptides might stem from a paradoxical requirement-the utility of such molecules in maintaining a diverse repertoire of pathogen-specific memory T cells in the body. Understanding the mechanisms underlying this intriguing nexus, therefore, has the potential to reveal therapeutic strategies not only for improving immune responses to chronic infections and tumors but also the long-term efficacy of vaccines aimed at cellular immune responses.
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Affiliation(s)
- Nevil J Singh
- Department of Microbiology and Immunology, University of Maryland School of Medicine, 685 W Baltimore St, HSF1, Room 380, Baltimore, MD 21201, USA
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22
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Abstract
Potentially harmful T cell precursors are removed from the conventional T cell pool by negative selection. This process can involve the induction of apoptosis, anergy, receptor editing or deviation into a regulatory T cell lineage. As such this process is essential for the health of an organism through its contribution to central and peripheral tolerance. While a great deal is known about the process, the precise mechanisms that regulate negative selection are not clear. Furthermore, the signals that distinguish the different forms of negative selection are not fully understood. Numerous models exist with the potential to address these questions in vitro and in vivo. This chapter describes methods of fetal thymic organ culture designed to analyze the signals that determine these unique cell fates.
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23
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Schatzlmaier P, Supper V, Göschl L, Zwirzitz A, Eckerstorfer P, Ellmeier W, Huppa JB, Stockinger H. Rapid multiplex analysis of lipid raft components with single-cell resolution. Sci Signal 2015; 8:rs11. [PMID: 26396269 DOI: 10.1126/scisignal.aac5584] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Lipid rafts, a distinct class of highly dynamic cell membrane microdomains, are integral to cell homeostasis, differentiation, and signaling. However, their quantitative examination is challenging when working with rare cells, developmentally heterogeneous cell populations, or molecules that only associate weakly with lipid rafts. We present a fast biochemical method, which is based on lipid raft components associating with the nucleus upon partial lysis during centrifugation through nonionic detergent. Requiring little starting material or effort, our protocol enabled the multidimensional flow cytometric quantitation of raft-resident proteins with single-cell resolution, thereby assessing the membrane components from a few cells in complex cell populations, as well as their dynamics resulting from cell signaling, differentiation, or genetic mutation.
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Affiliation(s)
- Philipp Schatzlmaier
- Institute for Hygiene and Applied Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Lazarettgasse 19, A-1090 Vienna, Austria
| | - Verena Supper
- Institute for Hygiene and Applied Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Lazarettgasse 19, A-1090 Vienna, Austria
| | - Lisa Göschl
- Institute of Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Lazarettgasse 19, A-1090 Vienna, Austria. Division of Rheumatology, Department of Internal Medicine III, Medical University of Vienna, Währinger Gürtel 18-20, A-1090 Vienna, Austria
| | - Alexander Zwirzitz
- Institute for Hygiene and Applied Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Lazarettgasse 19, A-1090 Vienna, Austria
| | - Paul Eckerstorfer
- Institute for Hygiene and Applied Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Lazarettgasse 19, A-1090 Vienna, Austria
| | - Wilfried Ellmeier
- Institute of Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Lazarettgasse 19, A-1090 Vienna, Austria
| | - Johannes B Huppa
- Institute for Hygiene and Applied Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Lazarettgasse 19, A-1090 Vienna, Austria.
| | - Hannes Stockinger
- Institute for Hygiene and Applied Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Lazarettgasse 19, A-1090 Vienna, Austria.
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24
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Indoctrinating T cells to attack pathogens through homeschooling. Trends Immunol 2015; 36:337-43. [PMID: 25979654 DOI: 10.1016/j.it.2015.04.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Revised: 04/15/2015] [Accepted: 04/15/2015] [Indexed: 12/14/2022]
Abstract
Adaptive immunity is predicated on the ability of the T cell repertoire to have pre-existing specificity for the universe of potential pathogens. Recent findings suggest that T cell receptor (TCR)-self-major histocompatibility protein (pMHC) interactions limit autoimmune responses while enhancing T cell response to foreign antigens. We review these findings here, placing them in context of the current understanding of how TCR-self-pMHC interactions regulate T cell activation thresholds, and suggest that TCR-self-pMHC interactions increase the efficiency of the T cell repertoire by giving a competitive advantage to peptide cross-reactive T cells. We propose that self-reactivity and peptide cross-reactivity are controlled by particular CDR3 sequence motifs, which would allow thymic selection to contribute to solving the feat of broad pathogen specificity by exporting T cells that are pre-screened by positive and negative selection for the ability to be 'moderately' peptide cross-reactive.
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25
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Abstract
Dynamic tuning of cellular responsiveness as a result of repeated stimuli improves the ability of cells to distinguish physiologically meaningful signals from each other and from noise. In particular, lymphocyte activation thresholds are subject to tuning, which contributes to maintaining tolerance to self-antigens and persisting foreign antigens, averting autoimmunity and immune pathogenesis, but allowing responses to strong, structured perturbations that are typically associated with acute infection. Such tuning is also implicated in conferring flexibility to positive selection in the thymus, in controlling the magnitude of the immune response, and in generating memory cells. Additional functional properties are dynamically and differentially tuned in parallel via subthreshold contact interactions between developing or mature lymphocytes and self-antigen-presenting cells. These interactions facilitate and regulate lymphocyte viability, maintain their functional integrity, and influence their responses to foreign antigens and accessory signals, qualitatively and quantitatively. Bidirectional tuning of T cells and antigen-presenting cells leads to the definition of homeostatic set points, thus maximizing clonal diversity.
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Affiliation(s)
- Zvi Grossman
- Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892; ,
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26
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Blyuss KB, Nicholson LB. Understanding the roles of activation threshold and infections in the dynamics of autoimmune disease. J Theor Biol 2014; 375:13-20. [PMID: 25150457 DOI: 10.1016/j.jtbi.2014.08.019] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Revised: 06/30/2014] [Accepted: 08/11/2014] [Indexed: 12/21/2022]
Abstract
Onset and development of autoimmunity have been attributed to a number of factors, including genetic predisposition, age and different environmental factors. In this paper we discuss mathematical models of autoimmunity with an emphasis on two particular aspects of immune dynamics: breakdown of immune tolerance in response to an infection with a pathogen, and interactions between T cells with different activation thresholds. We illustrate how the explicit account of T cells with different activation thresholds provides a viable model of immune dynamics able to reproduce several types of immune behaviour, including normal clearance of infection, emergence of a chronic state, and development of a recurrent infection with autoimmunity. We discuss a number of open research problems that can be addressed within the same modelling framework.
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Affiliation(s)
- K B Blyuss
- Department of Mathematics, University of Sussex, Falmer, Brighton BN1 9QH, UK.
| | - L B Nicholson
- School of Cellular and Molecular Medicine & School of Clinical Sciences, University of Bristol, University Walk, Bristol BS8 1TD, UK.
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27
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Fu G, Rybakin V, Brzostek J, Paster W, Acuto O, Gascoigne NRJ. Fine-tuning T cell receptor signaling to control T cell development. Trends Immunol 2014; 35:311-8. [PMID: 24951034 PMCID: PMC4119814 DOI: 10.1016/j.it.2014.05.003] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Revised: 04/24/2014] [Accepted: 05/12/2014] [Indexed: 01/23/2023]
Abstract
T cell development from immature CD4(+)CD8(+) double-positive (DP) thymocytes to the mature CD4 or CD8 single-positive (SP) stage requires proper T cell receptor (TCR) signaling. The current working model of thymocyte development is that the strength of the TCR-mediated signal - from little-or-none, through intermediate, to strong - received by the immature cells determines whether they will undergo death by neglect, positive selection, or negative selection, respectively. In recent years, several developmentally regulated, stage-specifically expressed proteins and miRNAs have been found that act like fine-tuners for signal transduction and propagation downstream of the TCR. This allows them to govern thymocyte positive selection. Here, we summarize recent findings on these molecules and suggest new concepts of TCR positive-selection signaling.
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Affiliation(s)
- Guo Fu
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Vasily Rybakin
- Department of Microbiology, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore 117597
| | - Joanna Brzostek
- Department of Microbiology, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore 117597
| | - Wolfgang Paster
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Oreste Acuto
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Nicholas R J Gascoigne
- Department of Microbiology, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore 117597.
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Distinct phases in the positive selection of CD8+ T cells distinguished by intrathymic migration and T-cell receptor signaling patterns. Proc Natl Acad Sci U S A 2014; 111:E2550-8. [PMID: 24927565 DOI: 10.1073/pnas.1408482111] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Positive selection of CD8 T cells in the thymus is thought to be a multistep process lasting 3-4 d; however, the discrete steps involved are poorly understood. Here, we examine phenotypic changes, calcium signaling, and intrathymic migration in a synchronized cohort of MHC class I-specific thymocytes undergoing positive selection in situ. Transient elevations in intracellular calcium concentration ([Ca(2+)]i) and migratory pauses occurred throughout the first 24 h of positive selection, becoming progressively briefer and accompanied by a gradual shift in basal [Ca(2+)]i over time. Changes in chemokine-receptor expression and relocalization from the cortex to medulla occurred between 12 and 24 h after the initial encounter with positive-selecting ligands, a time frame at which the majority of thymocytes retain CD4 and CD8 expression and still require T-cell receptor (TCR) signaling to efficiently complete positive selection. Our results identify distinct phases in the positive selection of MHC class I-specific thymocytes that are distinguished by their TCR-signaling pattern and intrathymic location and provide a framework for understanding the multistep process of positive selection in the thymus.
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29
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Rojo JM, Ojeda G, Acosta YY, Montes-Casado M, Criado G, Portolés P. Characteristics of TCR/CD3 complex CD3{varepsilon} chains of regulatory CD4+ T (Treg) lymphocytes: role in Treg differentiation in vitro and impact on Treg in vivo. J Leukoc Biol 2013; 95:441-50. [PMID: 24212096 DOI: 10.1189/jlb.1112584] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Tregs are anergic CD4(+)CD25(+)Foxp3(+) T lymphocytes exerting active suppression to control immune and autoimmune responses. However, the factors in TCR recognition underlying Treg differentiation are unclear. Based on our previous data, we hypothesized that Treg TCR/CD3 antigen receptor complexes might differ from those of CD4(+)CD25(-) Tconv. Expression levels of TCR/CD3, CD3ε,ζ chains, or other molecules involved in antigen signaling and the characteristics of CD3ε chains were analyzed in thymus or spleen Treg cells from normal mice. Tregs had quantitative and qualitatively distinct TCR/CD3 complexes and CD3ε chains. They expressed significantly lower levels of the TCR/CD3 antigen receptor, CD3ε chains, TCR-ζ chain, or the CD4 coreceptor than Tconv. Levels of kinases, adaptor molecules involved in TCR signaling, and early downstream activation pathways were also lower in Tregs than in Tconv. Furthermore, TCR/CD3 complexes in Tregs were enriched in CD3ε chains conserving their N-terminal, negatively charged amino acid residues; this trait is linked to a higher activation threshold. Transfection of mutant CD3ε chains lacking these residues inhibited the differentiation of mature CD4(+)Foxp3(-) T lymphocytes into CD4(+)Foxp3(+) Tregs, and differences in CD3ε chain recognition by antibodies could be used to enrich for Tregs in vivo. Our results show quantitative and qualitative differences in the TCR/CD3 complex, supporting the hyporesponsive phenotype of Tregs concerning TCR/CD3 signals. These differences might reconcile avidity and flexible threshold models of Treg differentiation and be used to implement therapeutic approaches involving Treg manipulation.
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Affiliation(s)
- Jose M Rojo
- 2.Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu, 9, E-28040 Madrid, Spain.
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30
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Piragyte I, Jun CD. Actin engine in immunological synapse. Immune Netw 2012; 12:71-83. [PMID: 22916042 PMCID: PMC3422712 DOI: 10.4110/in.2012.12.3.71] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2012] [Revised: 05/11/2012] [Accepted: 05/19/2012] [Indexed: 01/09/2023] Open
Abstract
T cell activation and function require physical contact with antigen presenting cells at a specialized junctional structure known as the immunological synapse. Once formed, the immunological synapse leads to sustained T cell receptor-mediated signalling and stabilized adhesion. High resolution microscopy indeed had a great impact in understanding the function and dynamic structure of immunological synapse. Trends of recent research are now moving towards understanding the mechanical part of immune system, expanding our knowledge in mechanosensitivity, force generation, and biophysics of cell-cell interaction. Actin cytoskeleton plays inevitable role in adaptive immune system, allowing it to bear dynamic and precise characteristics at the same time. The regulation of mechanical engine seems very complicated and overlapping, but it enables cells to be very sensitive to external signals such as surface rigidity. In this review, we focus on actin regulators and how immune cells regulate dynamic actin rearrangement process to drive the formation of immunological synapse.
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Affiliation(s)
- Indre Piragyte
- Immune Synapse Research Center and Cell Dynamics Research Center, School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
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31
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Abstract
Understanding the thymic processes that support the generation of functionally competent and self-tolerant lymphocytes requires dissection of the T-cell receptor (TCR) response to ligands of different affinities. In spatially segregated regions of the thymus, with unique expression of proteases and cytokines, TCR affinity guides a number of cell fate decisions. Yet affinity alone does not explain the selection paradox. Increasing evidence suggests that the 'altered peptide' model of the 1980s together with the affinity model might best explain how the thymus supports conventional and regulatory T-cell development. Development of new tools to study the strength of TCR signals perceived by T cells, novel regulatory T-cell transgenic mice, and tetramer enrichment strategies have provided an insight into the nature of TCR signals perceived during thymocyte development. These topics are discussed and support for the prevailing hypotheses is presented.
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Affiliation(s)
- Amy E Moran
- Center for Immunology, University of Minnesota, Minneapolis, MN 55414, USA
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Subcellular distribution of Lck during CD4 T-cell maturation in the thymic medulla regulates the T-cell activation threshold. Proc Natl Acad Sci U S A 2012; 109:7415-20. [PMID: 22529380 DOI: 10.1073/pnas.1119272109] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Mature peripheral T cells respond to foreign but not to self-antigens. During development in the thymus, deletion of high-affinity self-reactive immature thymocytes contributes to tolerance of mature T cells. However, double-positive thymocytes are positively selected to survive if they respond to self-peptide-MHC complexes; thus, there must be mechanisms to prevent overt reactivity to those same complexes in the periphery. "Developmental tuning" is the active process through which T-cell receptor (TCR)-associated signaling pathways of single-positive (SP) thymocytes are attenuated to respond appropriately to self-peptide-MHC complexes in the periphery. We previously showed that MHC class II expression in the thymic medulla was necessary to tune CD4(+) SP (CD4 SP) thymocytes. CD4 SP thymocytes from mice lacking medullary MHC class II expression had inappropriately enhanced proximal TCR signaling to low-affinity self-ligands that was associated with altered cellular distribution of the tyrosine kinase Lck. Now, we report that activation of both tuned and untuned CD4 SP thymocytes is Lck-dependent. Untuned CD4 SP cells contain a pool of Lck with increased basal phosphorylation that is not associated with the CD4 coreceptor. Phosphorylation of this pool of Lck decreases with tuning. Immunogold transmission electron microscopy of membrane sheets permitted direct visualization of Lck. In the absence of tuning, a significant proportion of Lck and the TCR subunit CD3ζ are expressed on the same protein island; this close association of Lck and the TCR probably explains the enhanced activation of untuned CD4 SP cells. Thus, changes in membrane topography during thymic maturation determine the set point for TCR responsiveness.
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Abstract
A fundamental property of the immune system is its ability to mediate self-defense with a minimal amount of collateral damage to the host. The system uses several different mechanisms to achieve this goal, which is collectively referred to as the "process of immunological tolerance." This article provides an introductory historical overview to these various mechanisms, which are discussed in greater detail throughout this collection, and then briefly describes what happens when this process fails, a state referred to as "autoimmunity."
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Affiliation(s)
- Ronald H Schwartz
- Laboratory of Cellular and Molecular Immunology, NIAID, National Institutes of Health, Bethesda, Maryland 20892-0420, USA.
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34
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Stritesky GL, Jameson SC, Hogquist KA. Selection of self-reactive T cells in the thymus. Annu Rev Immunol 2011; 30:95-114. [PMID: 22149933 DOI: 10.1146/annurev-immunol-020711-075035] [Citation(s) in RCA: 237] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
On the whole, the healthy adaptive immune system is responsive to foreign antigens and tolerant to self. However, many individual lymphocytes have, and even require, substantial self-reactivity for their particular functions in immunity. In this review, we discuss several populations of lymphocytes that are thought to experience agonist stimulation through the T cell receptor during selection: nTreg cells, iNKT cells, nIELs, and nTh17s. We discuss the nature of this self-reactivity, how it compares with conventional T cells, and why it is important for overall immune health. We also outline molecular pathways unique to each lineage and consider possible commonalities to their development and survival.
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Affiliation(s)
- Gretta L Stritesky
- Center for Immunology and Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, Minnesota 55455, USA
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35
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Lykken EA, Li QJ. microRNAs at the regulatory frontier: an investigation into how microRNAs impact the development and effector functions of CD4 T cells. Immunol Res 2011; 49:87-96. [PMID: 21191665 DOI: 10.1007/s12026-010-8196-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
CD4 T cells are an integral part of adaptive immunity. microRNAs have been identified as fundamental regulators of post-transcriptional programs and to play roles in T lymphocytes' development, differentiation, and effector functions. To better understand the role of miRNAs in T cells and to identify potential therapeutic tools and targets, we have undertaken studies of miRNAs that modulate or are modulated by T-cell receptor signaling. We identified miR-181a as a key regulator of TCR signaling strength, and hence T-cell development, and the miR-17-92 cluster as an important player in CD4 T cells' response against antigens. These discoveries, coupled with work by other researchers, reveal the power and importance of miRNA-mediated regulation in T-cell responses and offer new insights into the burgeoning field of immunoregulation.
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Affiliation(s)
- Erik Allen Lykken
- Department of Immunology, Duke University Medical Center, Durham, NC 27710, USA
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36
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Moran AE, Holzapfel KL, Xing Y, Cunningham NR, Maltzman JS, Punt J, Hogquist KA. T cell receptor signal strength in Treg and iNKT cell development demonstrated by a novel fluorescent reporter mouse. ACTA ACUST UNITED AC 2011; 208:1279-89. [PMID: 21606508 PMCID: PMC3173240 DOI: 10.1084/jem.20110308] [Citation(s) in RCA: 771] [Impact Index Per Article: 59.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The ability of antigen receptors to engage self-ligands with varying affinity is crucial for lymphocyte development. To further explore this concept, we generated transgenic mice expressing GFP from the immediate early gene Nr4a1 (Nur77) locus. GFP was up-regulated in lymphocytes by antigen receptor stimulation but not by inflammatory stimuli. In T cells, GFP was induced during positive selection, required major histocompatibility complex for maintenance, and directly correlated with the strength of T cell receptor (TCR) stimulus. Thus, our results define a novel tool for studying antigen receptor activation in vivo. Using this model, we show that regulatory T cells (T(reg) cells) and invariant NKT cells (iNKT cells) perceived stronger TCR signals than conventional T cells during development. However, although T(reg) cells continued to perceive strong TCR signals in the periphery, iNKT cells did not. Finally, we show that T(reg) cell progenitors compete for recognition of rare stimulatory TCR self-ligands.
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Affiliation(s)
- Amy E Moran
- Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, MN 55414, USA
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37
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Computational analysis of T cell receptor signaling and ligand discrimination--past, present, and future. FEBS Lett 2010; 584:4814-22. [PMID: 20965176 DOI: 10.1016/j.febslet.2010.10.027] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2010] [Revised: 10/12/2010] [Accepted: 10/13/2010] [Indexed: 11/23/2022]
Abstract
Signaling through the T cell receptor for antigen (TCR) has been studied for years by conventional biochemical means. More recently, attempts have been made to develop computational models of signaling through this receptor, with a specific focus on understanding how this recognition system discriminates between closely related (self and non-self) ligands. Here we discuss recent advances centered on the role of feedback regulation, especially the key finding that a combination of digital and analog control circuits is fundamental to the discrimination properties of the TCR. We end by pointing to future, more biologically accurate models that incorporate spatial aspects of molecular organization in antigen-engaged T lymphocytes with this underlying biochemistry.
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38
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39
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Abstract
The development of T cells in the thymus involves several differentiation and proliferation events, during which hematopoietic precursors give rise to T cells ready to respond to antigen stimulation and undergo effector differentiation. This review addresses signaling and transcriptional checkpoints that control the intrathymic journey of T cell precursors. We focus on the divergence of alphabeta and gammadelta lineage cells and the elaboration of the alphabeta T cell repertoire, with special emphasis on the emergence of transcriptional programs that direct lineage decisions.
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MESH Headings
- Animals
- Cell Differentiation/genetics
- Cell Differentiation/immunology
- Cell Lineage
- Gene Expression Regulation/immunology
- Humans
- Receptors, Antigen, T-Cell, alpha-beta/genetics
- Receptors, Antigen, T-Cell, alpha-beta/immunology
- Receptors, Antigen, T-Cell, gamma-delta/genetics
- Receptors, Antigen, T-Cell, gamma-delta/immunology
- Signal Transduction/genetics
- Signal Transduction/immunology
- T-Lymphocytes/cytology
- T-Lymphocytes/immunology
- Thymus Gland/cytology
- Thymus Gland/immunology
- Transcription, Genetic/genetics
- Transcription, Genetic/immunology
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Affiliation(s)
- Andrea C Carpenter
- Laboratory of Immune Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
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40
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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] [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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41
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Coward J, Germain RN, Altan-Bonnet G. Perspectives for computer modeling in the study of T cell activation. Cold Spring Harb Perspect Biol 2010; 2:a005538. [PMID: 20516137 DOI: 10.1101/cshperspect.a005538] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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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42
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Jonsson AH, Yang L, Kim S, Taffner SM, Yokoyama WM. Effects of MHC class I alleles on licensing of Ly49A+ NK cells. THE JOURNAL OF IMMUNOLOGY 2010; 184:3424-32. [PMID: 20194719 DOI: 10.4049/jimmunol.0904057] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
NK cells are innate immune lymphocytes that can react to cells lacking self-MHC class I. However, NK cells that cannot engage self-MHC through an inhibitory receptor are resistant to stimulation through their activation receptors. To become licensed (i.e., functionally competent to be triggered through its activation receptors), an NK cell must engage host MHC class I via a MHC class I-specific inhibitory receptor, such as a member of the murine Ly49 family. To explore potential determinants of NK cell licensing on a single Ly49 receptor, we have investigated the relative licensing impacts of the b, d, k, q, r, and s H2 haplotypes on Ly49A(+) NK cells. The results indicate that licensing is essentially analog but is saturated by moderate-binding MHC class I ligands. Interestingly, licensing exhibited a strong inverse correlation with a measure of cis engagement of Ly49A. Finally, licensing of Ly49A(+) NK cells was found to be less sensitive to MHC class I engagement than Ly49A-mediated effector inhibition, suggesting that licensing establishes a margin of safety against NK cell autoreactivity.
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Affiliation(s)
- A Helena Jonsson
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
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43
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Crites TJ, Varma R. On the issue of peptide recognition in T cell development. SELF/NONSELF 2010; 1:55-61. [PMID: 21559177 PMCID: PMC3091603 DOI: 10.4161/self.1.1.10962] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2009] [Revised: 12/16/2009] [Accepted: 12/17/2009] [Indexed: 11/19/2022]
Abstract
CD4-CD8 double positive (DP) thymocytes undergo a differentiation process in the thymus where they are selected based on their ability to recognize peptide antigens presented on self major histocompatibility complex (MHC) molecules. The first stage of this process is positive selection, a quality-control mechanism which ensures that the T cell receptors (TCR) presented on developing thymocytes can transmit signals via peptides presented on either MHC class I (MHC1) or MHC class II (MHC2) molecules. Work over the past decade has revealed that the peptides that drive positive selection of both CD4 and CD8 lineage cells deliver only weak TCR signals. In line with these observations, specialized protein degradation machineries have been discovered in the thymic cortex that presumably generate specialized low-affinity peptide repertoires for presentation on MHC1 and MHC2 molecules. TCR signals transduced through these weak-affinity ligands in the early stages of positive selection alter the kinetics of expression of CD4 and CD8 molecules and play a crucial role in commitment of thymocytes to either the CD4 or CD8 lineages. In this work, we review the experiments that explore the peptide repertoires that are presented to developing thymocytes during positive selection, the observed signaling patterns that lead to CD4 versus CD8 lineage commitment, and speculate about how specialized organization of the signaling machinery in DP thymocytes may allow for efficient transduction of weak signals during the course of positive selection.
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Affiliation(s)
- Travis J Crites
- Laboratory of Cellular and Molecular Immunology; National Institute of Allergy and Infectious Diseases; National Institutes of Health; Bethesda, MD USA
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44
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Naive T cell homeostasis: from awareness of space to a sense of place. Nat Rev Immunol 2009; 9:823-32. [PMID: 19935802 DOI: 10.1038/nri2657] [Citation(s) in RCA: 284] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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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45
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Stephen TL, Tikhonova A, Riberdy JM, Laufer TM. The activation threshold of CD4+ T cells is defined by TCR/peptide-MHC class II interactions in the thymic medulla. THE JOURNAL OF IMMUNOLOGY 2009; 183:5554-62. [PMID: 19843939 DOI: 10.4049/jimmunol.0901104] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Immature thymocytes that are positively selected based upon their response to self-peptide-MHC complexes develop into mature T cells that are not overtly reactive to those same complexes. Developmental tuning is the active process through which TCR-associated signaling pathways of single-positive thymocytes are attenuated to respond appropriately to the peptide-MHC molecules that will be encountered in the periphery. In this study, we explore the mechanisms that regulate the tuning of CD4(+) single-positive T cells to MHC class II encountered in the thymic medulla. Experiments with murine BM chimeras demonstrate that tuning can be mediated by MHC class II expressed by either thymic medullary epithelial cells or thymic dendritic cells. Tuning does not require the engagement of CD4 by MHC class II on stromal cells. Rather, it is mediated by interactions between MHC class II and the TCR. To understand the molecular changes that distinguish immature hyperactive T cells from tuned mature CD4(+) T cells, we compared their responses to TCR stimulation. The altered response of mature CD4 single-positive thymocytes is characterized by the inhibition of ERK activation by low-affinity self-ligands and increased expression of the inhibitory tyrosine phosphatase SHP-1. Thus, persistent TCR engagement by peptide-MHC class II on thymic medullary stroma inhibits reactivity to self-Ags and prevents autoreactivity in the mature repertoire.
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Affiliation(s)
- Tom Li Stephen
- Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
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46
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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 PMCID: PMC2757056 DOI: 10.1038/ni.1766] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [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 had high expression in thymocytes between the pre-T cell antigen receptor (pre-TCR) and positive-selection checkpoints and low expression in mature T cells. Themis-deficient thymocytes showed defective positive selection, which resulted in fewer mature thymocytes. Negative selection was also impaired in Themis-deficient mice. A greater percentage of Themis-deficient T cells had CD4(+)CD25(+)Foxp3(+) regulatory and CD62L(lo)CD44(hi) memory phenotypes than did wild-type T cells. In support of the idea that Themis is involved in TCR signaling, this protein was phosphorylated quickly after TCR stimulation and was needed for optimal TCR-driven calcium mobilization and activation of the kinase Erk.
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Affiliation(s)
- Guo Fu
- Department of Immunology and Microbial Science, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Sébastien Vallée
- Department of Immunology and Microbial Science, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Vasily Rybakin
- Department of Immunology and Microbial Science, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Marielena V. McGuire
- Department of Immunology and Microbial Science, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Jeanette Ampudia
- Department of Immunology and Microbial Science, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Claudia Brockmeyer
- T cell Signalling Laboratory, Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Mogjiborahman Salek
- T cell Signalling Laboratory, Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Paul R. Fallen
- Department of Immunology and Microbial Science, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - John A.H. Hoerter
- Department of Immunology and Microbial Science, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Anil Munshi
- Department of Immunology and Microbial Science, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Yina H. Huang
- Department of Immunology and Microbial Science, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Jianfang Hu
- Department of Immunology and Microbial Science, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Howard S. Fox
- Department of Molecular and Integrative Neurosciences, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Karsten Sauer
- Department of Immunology and Microbial Science, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Oreste Acuto
- T cell Signalling Laboratory, Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - 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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N-terminal negatively charged residues in CD3varepsilon chains as a phylogenetically conserved trait potentially yielding isoforms with different isoelectric points: analysis of human CD3varepsilon chains. Immunol Lett 2009; 126:8-15. [PMID: 19616027 DOI: 10.1016/j.imlet.2009.07.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2009] [Revised: 06/23/2009] [Accepted: 07/09/2009] [Indexed: 11/21/2022]
Abstract
CD3varepsilon chains are essential to the structure, expression and signaling of T cell receptors. Here, we extend to human CD3varepsilon our previous data in mouse CD3varepsilon showing that, in T cells, proteolytic processing of the acidic N-terminal sequence of CD3varepsilon chains generate distinct polypeptide species that can be identified by two-dimension (IEF-SDS PAGE) electrophoresis and immunoblot. This was shown first by showing the processing of a fusion protein of GFP and the extracellular domain of mouse CD3varepsilon (mCD3GFP) expressed in Jurkat cells. Secondly, pI heterogeneity was also found in human CD3varepsilon chains immunoprecipitated from the surface of Jurkat cells or PHA blasts of human blood T lymphocytes. Comparison of CD3varepsilon chains from 27 different species shows that their N-terminal sequences share a strong acidic nature, despite the large differences in terms of length and composition, even among closely related species. Our results suggest that generation of CD3varepsilon chain isoforms with different N-terminal sequence and pI is a general phenomenon. Thus, as previously observed in the mouse, the relative abundance of CD3varepsilon chain species might regulate TCR/CD3 structure and function, including the strength of the interactions between CD3 dimers and the TCR clonotypic receptors, as well as TCR/CD3 activation thresholds. Interestingly, CD3varepsilon chains from 7 out of 27 species studied have putative N-glycosylation (NxS or NxT) motifs in their Ig extracellular domain. Their location, plus the conservation of residues involved in domain organization, the interactions with other CD3 chains, or the TCR, and signal triggering add new data useful to establish a permissive topology for the interaction between CD3 dimers and the TCR chains.
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KSR1 modulates the sensitivity of mitogen-activated protein kinase pathway activation in T cells without altering fundamental system outputs. Mol Cell Biol 2009; 29:2082-91. [PMID: 19188442 DOI: 10.1128/mcb.01634-08] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Mitogen-activated protein kinase (MAPK) cascades are evolutionarily conserved signaling pathways that regulate cell fate decisions. They generate a wide range of signal outputs, including graded and digital responses. In T cells, MAPK activation is digital in response to T-cell-receptor stimulation; however, whether other receptors on T cells that lead to MAPK activation are graded or digital is unknown. Here we evaluate MAPK activation in T cells at the single-cell level. We show that T cells responded digitally to stimulation with superantigen-loaded antigen-presenting cells, whereas they responded in a graded manner to the chemokine SDF-1, demonstrating that the system output of the MAPK module is highly plastic and determined by components upstream of the MAPK module. These findings also confirm that different MAPK system outputs are used by T cells to control discrete biological functions. Scaffold proteins are essential for proper MAPK signaling and function as they physically assemble multiple components and regulators of MAPK cascades. We found that the scaffold protein KSR1 regulated the threshold required for MAPK activation in T cells without affecting the nature of the response. We conclude that KSR1 plays a central role in determining the sensitivity of T-cell responses and is thus well positioned as a key control point.
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Maric M, Barjaktarevic I, Bogunovic B, Stojakovic M, Maric C, Vukmanovic S. Cutting Edge: Developmental Up-Regulation of IFN-γ-Inducible Lysosomal Thiol Reductase Expression Leads to Reduced T Cell Sensitivity and Less Severe Autoimmunity. THE JOURNAL OF IMMUNOLOGY 2009; 182:746-50. [DOI: 10.4049/jimmunol.182.2.746] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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Coronin-1A links cytoskeleton dynamics to TCR alpha beta-induced cell signaling. PLoS One 2008; 3:e3467. [PMID: 18941544 PMCID: PMC2568942 DOI: 10.1371/journal.pone.0003467] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2008] [Accepted: 09/20/2008] [Indexed: 11/19/2022] Open
Abstract
Actin polymerization plays a critical role in activated T lymphocytes both in regulating T cell receptor (TCR)-induced immunological synapse (IS) formation and signaling. Using gene targeting, we demonstrate that the hematopoietic specific, actin- and Arp2/3 complex-binding protein coronin-1A contributes to both processes. Coronin-1A-deficient mice specifically showed alterations in terminal development and the survival of αβT cells, together with defects in cell activation and cytokine production following TCR triggering. The mutant T cells further displayed excessive accumulation yet reduced dynamics of F-actin and the WASP-Arp2/3 machinery at the IS, correlating with extended cell-cell contact. Cell signaling was also affected with the basal activation of the stress kinases sAPK/JNK1/2; and deficits in TCR-induced Ca2+ influx and phosphorylation and degradation of the inhibitor of NF-κB (IκB). Coronin-1A therefore links cytoskeleton plasticity with the functioning of discrete TCR signaling components. This function may be required to adjust TCR responses to selecting ligands accounting in part for the homeostasis defect that impacts αβT cells in coronin-1A deficient mice, with the exclusion of other lympho/hematopoietic lineages.
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