1
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Eggert J, Zinzow-Kramer WM, Hu Y, Kolawole EM, Tsai YL, Weiss A, Evavold BD, Salaita K, Scharer CD, Au-Yeung BB. Cbl-b mitigates the responsiveness of naive CD8 + T cells that experience extensive tonic T cell receptor signaling. Sci Signal 2024; 17:eadh0439. [PMID: 38319998 PMCID: PMC10897907 DOI: 10.1126/scisignal.adh0439] [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: 02/07/2023] [Accepted: 01/18/2024] [Indexed: 02/08/2024]
Abstract
Naive T cells experience tonic T cell receptor (TCR) signaling in response to self-antigens presented by major histocompatibility complex (MHC) in secondary lymphoid organs. We investigated how relatively weak or strong tonic TCR signals influence naive CD8+ T cell responses to stimulation with foreign antigens. The heterogeneous expression of Nur77-GFP, a transgenic reporter of tonic TCR signaling, in naive CD8+ T cells suggests variable intensities or durations of tonic TCR signaling. Although the expression of genes associated with acutely stimulated T cells was increased in Nur77-GFPHI cells, these cells were hyporesponsive to agonist TCR stimulation compared with Nur77-GFPLO cells. This hyporesponsiveness manifested as diminished activation marker expression and decreased secretion of IFN-γ and IL-2. The protein abundance of the ubiquitin ligase Cbl-b, a negative regulator of TCR signaling, was greater in Nur77-GFPHI cells than in Nur77-GFPLO cells, and Cbl-b deficiency partially restored the responsiveness of Nur77-GFPHI cells. Our data suggest that the cumulative effects of previously experienced tonic TCR signaling recalibrate naive CD8+ T cell responsiveness. These changes include gene expression changes and negative regulation partially dependent on Cbl-b. This cell-intrinsic negative feedback loop may enable the immune system to restrain naive CD8+ T cells with higher self-reactivity.
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Affiliation(s)
- Joel Eggert
- Division of Immunology, Lowance Center for Human Immunology, Department of Medicine, Emory University; Atlanta, 30322, USA
| | - Wendy M. Zinzow-Kramer
- Division of Immunology, Lowance Center for Human Immunology, Department of Medicine, Emory University; Atlanta, 30322, USA
| | - Yuesong Hu
- Department of Chemistry, Emory University; Atlanta, 30322, USA
| | - Elizabeth M. Kolawole
- Department of Pathology, University of Utah School of Medicine, Salt Lake City, 84112, USA
| | - Yuan-Li Tsai
- Rosalind Russell and Ephraim P. Engleman Rheumatology Research Center, Departments of Medicine and of Microbiology and Immunology, University of California, San Francisco; San Francisco, 94143, USA
| | - Arthur Weiss
- Rosalind Russell and Ephraim P. Engleman Rheumatology Research Center, Departments of Medicine and of Microbiology and Immunology, University of California, San Francisco; San Francisco, 94143, USA
| | - Brian D. Evavold
- Department of Pathology, University of Utah School of Medicine, Salt Lake City, 84112, USA
| | - Khalid Salaita
- Department of Chemistry, Emory University; Atlanta, 30322, USA
| | | | - Byron B. Au-Yeung
- Division of Immunology, Lowance Center for Human Immunology, Department of Medicine, Emory University; Atlanta, 30322, USA
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2
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Chen Y, Wu X, Lai J, Yan B, Gong Q. Molecular mechanisms of physiological change under acute total dissolved gas supersaturation stress in yellow catfish (Pelteobagrus fulvidraco). ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:97911-97924. [PMID: 37603244 DOI: 10.1007/s11356-023-29157-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Accepted: 07/31/2023] [Indexed: 08/22/2023]
Abstract
During the dam discharging period, the strong aeration of high-speed water leads to the supersaturation of total dissolved gas (TDG) in the downstream water, which causes gas bubble disease (GBD) in fish and threatens their survival. TDG supersaturation has now become an ecological and environmental issue of global concern; however, the molecular mechanism underlying the physiological effect of TDG supersaturation on fish is poorly known. Here, we comprehensively investigated the effect of TDG supersaturation on Pelteobagrus fulvidraco at the histopathological, biochemical, transcriptomic, and metabolomic levels. After exposure to 116% TDG, P. fulvidraco exhibited classic GBD symptoms and pathological changes in gills. The level of superoxide dismutase was highly significantly decreased. Transcriptomic results revealed that heat shock proteins (HSPs) and a large number of genes involved in immunity were increased by TDG stress. A key environmental sensor PI3K/Akt/mTOR pathway was significantly stimulated for defence against stress. Integrated transcriptomic and metabolomic analyses revealed that key metabolites and genes were upregulated in the triacylglycerol synthesis pathway and that amino acid levels decreased, which might be associated with TDG supersaturation stress. The present study demonstrated that TDG supersaturation could cause severe physiological damage in fish. HSP genes, immune functions, and energy metabolic pathways were enhanced to counteract the adverse effects.
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Affiliation(s)
- Yeyu Chen
- The Fishery Institute of the Sichuan Academy of Agricultural Sciences, Chengdu, 611730, China
| | - Xiaoyun Wu
- The Fishery Institute of the Sichuan Academy of Agricultural Sciences, Chengdu, 611730, China
| | - Jiansheng Lai
- The Fishery Institute of the Sichuan Academy of Agricultural Sciences, Chengdu, 611730, China
| | - Boqin Yan
- The Fishery Institute of the Sichuan Academy of Agricultural Sciences, Chengdu, 611730, China
| | - Quan Gong
- The Fishery Institute of the Sichuan Academy of Agricultural Sciences, Chengdu, 611730, China.
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3
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Eggert J, Zinzow-Kramer WM, Hu Y, Tsai YL, Weiss A, Salaita K, Scharer CD, Au-Yeung BB. Accumulation of TCR signaling from self-antigens in naive CD8 T cells mitigates early responsiveness. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.27.525946. [PMID: 36747815 PMCID: PMC9900884 DOI: 10.1101/2023.01.27.525946] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The cumulative effects of T cell receptor (TCR) signal transduction over extended periods of time influences T cell biology, such as the positive selection of immature thymocytes or the proliferative responses of naive T cells. Naive T cells experience recurrent TCR signaling in response to self-antigens in the steady state. However, how these signals influence the responsiveness of naive CD8+ T cells to subsequent agonist TCR stimulation remains incompletely understood. We investigated how naive CD8+ T cells that experienced relatively low or high levels of TCR signaling in response to self-antigens respond to stimulation with foreign antigens. A transcriptional reporter of Nr4a1 (Nur77-GFP) revealed substantial heterogeneity of the amount of TCR signaling naive CD8+ T cells accumulate in the steady state. Nur77-GFPHI cells exhibited diminished T cell activation and secretion of IFNγ and IL-2 relative to Nur77-GFPLO cells in response to agonist TCR stimulation. Differential gene expression analyses revealed upregulation of genes associated with acutely stimulated T cells in Nur77-GFPHI cells but also increased expression of negative regulators such as the phosphatase Sts1. Responsiveness of Nur77-GFPHI cells to TCR stimulation was partially restored at the level of IFNγ secretion by deficiency of Sts1 or the ubiquitin ligase Cbl-b. Our data suggest that extensive accumulation of TCR signaling during steady state conditions induces a recalibration of the responsiveness of naive CD8+ T cells through gene expression changes and negative regulation, at least in part, dependent on Sts1 and Cbl-b. This cell-intrinsic negative feedback loop may allow the immune system to limit the autoreactive potential of highly self-reactive naive CD8+ T cells.
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Affiliation(s)
- Joel Eggert
- Division of Immunology, Lowance Center for Human Immunology, Department of Medicine, Emory University
| | - Wendy M. Zinzow-Kramer
- Division of Immunology, Lowance Center for Human Immunology, Department of Medicine, Emory University
| | - Yuesong Hu
- Department of Chemistry, Emory University
| | - Yuan-Li Tsai
- Rosalind Russell and Ephraim P. Engleman Rheumatology Research Center, Departments of Medicine and of Microbiology and Immunology, University of California, San Francisco
| | - Arthur Weiss
- Rosalind Russell and Ephraim P. Engleman Rheumatology Research Center, Departments of Medicine and of Microbiology and Immunology, University of California, San Francisco
| | | | | | - Byron B. Au-Yeung
- Division of Immunology, Lowance Center for Human Immunology, Department of Medicine, Emory University
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4
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Samassa F, Mallone R. Self-antigens, benign autoimmunity and type 1 diabetes: a beta-cell and T-cell perspective. Curr Opin Endocrinol Diabetes Obes 2022; 29:370-378. [PMID: 35777965 DOI: 10.1097/med.0000000000000735] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
PURPOSE OF REVIEW Recent work using immunopeptidomics and deconvolution of the antigenic reactivity of islet-infiltrating CD8+ T cells has expanded our knowledge about the autoimmune target epitopes of type 1 diabetes. The stem-like properties of autoimmune CD8+ T cells have also been described. We here propose a possible link between these findings. RECENT FINDINGS Weak major histocompatibility complex (MHC)-binding epitopes list among the major targets of human islet-infiltrating CD8+ T cells, likely resulting in low peptide-MHC presentation that delivers weak T-cell receptor (TCR) signals, especially in the face of low-affinity autoimmune TCRs. These weak TCR signals may favor the maintenance of the partially differentiated stem-like phenotype recently described for islet-reactive CD8+ T cells in the blood and pancreatic lymph nodes. These weak TCR signals may also be physiological, reflecting the need for self-peptide-MHC contacts to maintain homeostatic T-cell survival and proliferation. These features may underlie the universal state of benign autoimmunity that we recently described, which is characterized by islet-reactive, naïve-like CD8+ T cells circulating in all individuals. SUMMARY These observations provide novel challenges and opportunities to develop circulating T-cell biomarkers for autoimmune staging. Therapeutic halting of islet autoimmunity may require targeting of stem-like T cells to blunt their self-regeneration.
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Affiliation(s)
| | - Roberto Mallone
- Institut Cochin, Université Paris Cité, CNRS, INSERM
- Assistance Publique Hôpitaux de Paris, Service de Diabétologie et Immunologie Clinique, Cochin Hospital, Paris, France
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5
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Mori M, Ruer-Laventie J, Duchemin W, Demougin P, Ndinyanka Fabrice T, Wymann MP, Pieters J. Suppression of caspase 8 activity by a coronin 1-PI3Kδ pathway promotes T cell survival independently of TCR and IL-7 signaling. Sci Signal 2021; 14:eabj0057. [PMID: 34932374 DOI: 10.1126/scisignal.abj0057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The control of T cell survival is crucial for defense against infectious pathogens or emerging cancers. Although the survival of peripheral naïve T cells has been proposed to be controlled by interleukin-7 (IL-7) signaling and T cell receptor (TCR) activation by peptide-loaded major histocompatibility complexes (pMHC), the essential roles for these pathways in thymic output and T cell proliferation have complicated the analysis of their contributions to T cell survival. Here, we showed that the WD repeat–containing protein coronin 1, which is dispensable for thymic selection and output, promoted naïve T cell survival in the periphery in a manner that was independent of TCR and IL-7 signaling. Coronin 1 was required for the maintenance of the basal activity of phosphoinositide 3-kinase δ (PI3Kδ), thereby suppressing caspase 8–mediated apoptosis. These results therefore reveal a coronin 1–dependent PI3Kδ pathway that is independent of pMHC:TCR and IL-7 signaling and essential for peripheral T cell survival.
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Affiliation(s)
- Mayumi Mori
- Biozentrum, University of Basel, Basel, Switzerland
| | | | - Wandrille Duchemin
- SIB Swiss Institute of Bioinformatics, Lausanne, Switzerland
- Center for Scientific Computing (sciCORE), University of Basel, Basel, Switzerland
| | - Philippe Demougin
- Biozentrum, Life Sciences Training Facility, University of Basel, Basel, Switzerland
| | | | | | - Jean Pieters
- Biozentrum, University of Basel, Basel, Switzerland
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6
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Shah K, Al-Haidari A, Sun J, Kazi JU. T cell receptor (TCR) signaling in health and disease. Signal Transduct Target Ther 2021; 6:412. [PMID: 34897277 PMCID: PMC8666445 DOI: 10.1038/s41392-021-00823-w] [Citation(s) in RCA: 133] [Impact Index Per Article: 44.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Revised: 11/02/2021] [Accepted: 11/02/2021] [Indexed: 12/18/2022] Open
Abstract
Interaction of the T cell receptor (TCR) with an MHC-antigenic peptide complex results in changes at the molecular and cellular levels in T cells. The outside environmental cues are translated into various signal transduction pathways within the cell, which mediate the activation of various genes with the help of specific transcription factors. These signaling networks propagate with the help of various effector enzymes, such as kinases, phosphatases, and phospholipases. Integration of these disparate signal transduction pathways is done with the help of adaptor proteins that are non-enzymatic in function and that serve as a scaffold for various protein-protein interactions. This process aids in connecting the proximal to distal signaling pathways, thereby contributing to the full activation of T cells. This review provides a comprehensive snapshot of the various molecules involved in regulating T cell receptor signaling, covering both enzymes and adaptors, and will discuss their role in human disease.
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Affiliation(s)
- Kinjal Shah
- Division of Translational Cancer Research, Department of Laboratory Medicine, Lund University, Lund, Sweden
- Lund Stem Cell Center, Department of Laboratory Medicine, Lund University, Lund, Sweden
| | - Amr Al-Haidari
- Clinical Genetics and Pathology, Skåne University Hospital, Region Skåne, Lund, Sweden
- Clinical Sciences Department, Surgery Research Unit, Lund University, Malmö, Sweden
| | - Jianmin Sun
- Division of Translational Cancer Research, Department of Laboratory Medicine, Lund University, Lund, Sweden
- Lund Stem Cell Center, Department of Laboratory Medicine, Lund University, Lund, Sweden
- NHC Key Laboratory of Metabolic Cardiovascular Diseases Research, Science and Technology center, School of Basic Medical Sciences, Ningxia Medical University, Yinchuan, China
| | - Julhash U Kazi
- Division of Translational Cancer Research, Department of Laboratory Medicine, Lund University, Lund, Sweden.
- Lund Stem Cell Center, Department of Laboratory Medicine, Lund University, Lund, Sweden.
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7
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Abstract
Conventional CD4+ and CD8+ T lymphocytes comprise a mixture of naive and memory cells. Generation and survival of these T-cell subsets is under strict homeostatic control and reflects contact with self-major histocompatibility complex (MHC) and certain cytokines. Naive T cells arise in the thymus via T-cell receptor (TCR)-dependent positive selection to self-peptide/MHC complexes and are then maintained in the periphery through self-MHC interaction plus stimulation via interleukin-7 (IL-7). By contrast, memory T cells are largely MHC-independent for their survival but depend strongly on stimulation via cytokines. Whereas typical memory T cells are generated in response to foreign antigens, some arise spontaneously through contact of naive precursors with self-MHC ligands; we refer to these cells as memory-phenotype (MP) T cells. In this review, we discuss the generation and homeostasis of naive T cells and these two types of memory T cells, focusing on their relative interaction with MHC ligands and cytokines.
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Affiliation(s)
- Takeshi Kawabe
- Department of Microbiology and Immunology, Tohoku University Graduate School of Medicine, Sendai, Miyagi 980-8575, Japan
| | - Jaeu Yi
- Division of Rheumatology, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri 63110, USA
| | - Jonathan Sprent
- Immunology Division, Garvan Institute of Medical Research, Darlinghurst, New South Wales 2010, Australia
- St. Vincent's Clinical School, University of New South Wales, Sydney, New South Wales 2010, Australia
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8
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Xia R, Yang M, Fu X, Du W, Gao X, Li G, Ranganathan S, Zhang X, Jiang J, Lu B. Differential Requirement of Beclin 1 for Regulating the Balance of Naïve and Activated CD4 + T Cells. Front Cell Dev Biol 2020; 8:834. [PMID: 32984329 PMCID: PMC7479058 DOI: 10.3389/fcell.2020.00834] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Accepted: 08/04/2020] [Indexed: 01/27/2023] Open
Abstract
Autophagy is highly regulated and plays a multitude of roles during T cell-mediated immune responses. It has been shown that autophagy deficiency in T cells results in a decrease in total T cells, including naïve T cells in young mice, but the mechanism is still not understood. Here, similar to what happened in young mice, we showed that T cell-specific deletion of Beclin 1/Atg6 (Becn1 −/−) resulted in decreases in the percentages of CD4+, CD8+, and regulatory T cells in adult mice. In addition, we found that the effector to naïve T cell ratio was increased in older mice. Also, as mice grew older, Becn1 −/− mice progressively lost weight and developed severe colitis. Analysis of inflamed tissues demonstrated increases in the portion and cytokine production of effector T cells. In contrast, the TCR-transgenic Becn1 −/− mice had similar numbers of naïve T cells compared to WT controls. Similar to bulk T cells, the TCR-transgenic Becn1 −/− T cells generated much lower numbers of effector T cells compared to WT controls after activation in vitro. These data suggest that autophagy is not required for maintaining the naïve T cell but required for the generation of effector T cells in vivo.
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Affiliation(s)
- Rui Xia
- Department of Immunology, Institute of Medical Biotechnology, Soochow University, Suzhou, China.,Department of Immunology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, United States.,Department of Oncology, The Second Affiliated Hospital of Soochow University, Soochow University, Suzhou, China
| | - Min Yang
- Department of Immunology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, United States.,Department of Oncology, The Third Affiliated Hospital of Soochow University, Changzhou, China
| | - Xiaorui Fu
- Department of Immunology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, United States.,Department of Oncology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Wenwen Du
- Department of Immunology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, United States
| | - Xin Gao
- Department of Immunology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, United States
| | - Gang Li
- Department of Immunology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, United States
| | | | - Xueguang Zhang
- Department of Oncology, The Second Affiliated Hospital of Soochow University, Soochow University, Suzhou, China
| | - Jingting Jiang
- Department of Oncology, The Third Affiliated Hospital of Soochow University, Changzhou, China
| | - Binfeng Lu
- Department of Immunology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, United States
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9
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Paprckova D, Stepanek O. Narcissistic T cells: reactivity to self makes a difference. FEBS J 2020; 288:1778-1788. [PMID: 32738029 DOI: 10.1111/febs.15498] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 06/22/2020] [Accepted: 07/25/2020] [Indexed: 12/15/2022]
Abstract
It has been appreciated for more than three decades that the interactions between the T-cell antigen receptor and self-antigens are the major determinants of the cell fates of developing thymocytes and the establishment of central tolerance. However, recent evidence shows that the level of self-reactivity substantially contributes to fate choices of positively selected mature T cells in homeostasis, as well as during immune responses. This implies that individual clones of peripheral T cells are predisposed to specific functional properties based on the self-reactivity of their antigen receptors. Overall, the relative difference in the self-reactivity among peripheral T cells is an important factor contributing to the diversity of T-cell responses to foreign antigens.
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Affiliation(s)
- Darina Paprckova
- Laboratory of Adaptive Immunity, Institute of Molecular Genetics, Czech Academy of Sciences, Prague, Czech Republic
| | - Ondrej Stepanek
- Laboratory of Adaptive Immunity, Institute of Molecular Genetics, Czech Academy of Sciences, Prague, Czech Republic
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10
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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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11
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Adaptation by naïve CD4 + T cells to self-antigen-dependent TCR signaling induces functional heterogeneity and tolerance. Proc Natl Acad Sci U S A 2019; 116:15160-15169. [PMID: 31285342 DOI: 10.1073/pnas.1904096116] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Naïve CD4+ T cells experience weak T cell receptor (TCR) signals induced by self-peptides presented by MHC II. To investigate how these "basal" TCR signals influence responses to agonist TCR ligand stimulation, we analyzed naïve CD4+ cells expressing varying amounts of CD5, Ly6C, and Nur77-GFP, markers that reflect the strength of basal TCR signaling. Phenotypic analyses indicate that the broadest range of basal TCR signal strength can be visualized by a combination of Nur77-GFP and Ly6C. A range of basal TCR signaling is detectable even in populations that express identical TCRs. Whereas moderate basal TCR signal strength correlates with higher IL-2 secretion at early time points following TCR stimulation, weak basal TCR signaling correlated with higher IL-2 secretion at later time points. We identify a population of Nur77-GFPHI Ly6C- cells that could not be reliably marked by either of CD5, Ly6C, or Nur77-GFP alone. These cells experience the strongest basal TCR signaling, consistently produce less IL-2, and express PD-1 and markers associated with anergy, such as Grail and Cbl-b. We propose that adaptation to the strength of basal TCR signaling drives the phenotypic and functional heterogeneity of naïve CD4+ cells.
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12
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Balyan R, Gund R, Chawla AS, Khare SP, Pradhan SJ, Rane S, Galande S, Durdik JM, George A, Bal V, Rath S. Correlation of cell-surface CD8 levels with function, phenotype and transcriptome of naive CD8 T cells. Immunology 2018; 156:384-401. [PMID: 30556901 DOI: 10.1111/imm.13036] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Revised: 11/20/2018] [Accepted: 11/21/2018] [Indexed: 11/27/2022] Open
Abstract
We have previously demonstrated co-receptor level-associated functional heterogeneity in apparently homogeneous naive peripheral CD4 T cells, dependent on MHC-mediated tonic signals. Maturation pathways can differ between naive CD4 and naive CD8 cells, so we tested whether the latter showed similar co-receptor level-associated functional heterogeneity. We report that, when either polyclonal and T-cell receptor (TCR)-transgenic monoclonal peripheral naive CD8 T cells from young mice were separated into CD8hi and CD8lo subsets, CD8lo cells responded poorly, but CD8hi and CD8lo subsets of CD8 single-positive (SP) thymocytes responded similarly. CD8lo naive CD8 T cells were smaller and showed lower levels of some cell-surface molecules, but higher levels of the negative regulator CD5. In addition to the expected peripheral decline in CD8 levels on transferred naive CD8 T cells in wild-type (WT) but not in MHC class I-deficient recipient mice, short-duration naive T-cell-dendritic cell (DC) co-cultures in vitro also caused co-receptor down-modulation in CD8 T cells but not in CD4 T cells. Constitutive pZAP70/pSyk and pERK levels ex vivo were lower in CD8lo naive CD8 T cells and dual-specific phosphatase inhibition partially rescued their hypo-responsiveness. Bulk mRNA sequencing showed major differences in the transcriptional landscapes of CD8hi and CD8lo naive CD8 T cells. CD8hi naive CD8 T cells showed enrichment of genes involved in positive regulation of cell cycle and survival. Our data show that naive CD8 T cells show major differences in their signaling, transcriptional and functional landscapes associated with subtly altered CD8 levels, consistent with the possibility of peripheral cellular aging.
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Affiliation(s)
- Renu Balyan
- National Institute of Immunology, New Delhi, India.,Yong Loo Lin School of Medicine, National University of Singapore, Singapore city, Singapore
| | - Rupali Gund
- National Institute of Immunology, New Delhi, India
| | | | - Satyajeet P Khare
- Indian Institute of Science Education and Research, Pune, India.,Symbiosis School of Biological Sciences, Pune, India
| | | | - Sanket Rane
- National Institute of Immunology, New Delhi, India
| | - Sanjeev Galande
- Indian Institute of Science Education and Research, Pune, India
| | | | - Anna George
- National Institute of Immunology, New Delhi, India
| | - Vineeta Bal
- National Institute of Immunology, New Delhi, India.,Indian Institute of Science Education and Research, Pune, India
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13
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Chouaki Benmansour N, Ruminski K, Sartre AM, Phelipot MC, Salles A, Bergot E, Wu A, Chicanne G, Fallet M, Brustlein S, Billaudeau C, Formisano A, Mailfert S, Payrastre B, Marguet D, Brasselet S, Hamon Y, He HT. Phosphoinositides regulate the TCR/CD3 complex membrane dynamics and activation. Sci Rep 2018; 8:4966. [PMID: 29563576 PMCID: PMC5862878 DOI: 10.1038/s41598-018-23109-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Accepted: 03/05/2018] [Indexed: 01/06/2023] Open
Abstract
Phosphoinositides (PIs) play important roles in numerous membrane-based cellular activities. However, their involvement in the mechanism of T cell receptor (TCR) signal transduction across the plasma membrane (PM) is poorly defined. Here, we investigate their role, and in particular that of phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] in TCR PM dynamics and activity in a mouse T-cell hybridoma upon ectopic expression of a PM-localized inositol polyphosphate-5-phosphatase (Inp54p). We observed that dephosphorylation of PI(4,5)P2 by the phosphatase increased the TCR/CD3 complex PM lateral mobility prior stimulation. The constitutive and antigen-elicited CD3 phosphorylation as well as the antigen-stimulated early signaling pathways were all found to be significantly augmented in cells expressing the phosphatase. Using state-of-the-art biophotonic approaches, we further showed that PI(4,5)P2 dephosphorylation strongly promoted the CD3ε cytoplasmic domain unbinding from the PM inner leaflet in living cells, thus resulting in an increased CD3 availability for interactions with Lck kinase. This could significantly account for the observed effects of PI(4,5)P2 dephosphorylation on the CD3 phosphorylation. Our data thus suggest that PIs play a key role in the regulation of the TCR/CD3 complex dynamics and activation at the PM.
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Affiliation(s)
| | - Kilian Ruminski
- Aix Marseille Univ, CNRS, INSERM, CIML, Centre d'Immunologie de Marseille-Luminy, Marseille, France
| | - Anne-Marie Sartre
- Aix Marseille Univ, CNRS, INSERM, CIML, Centre d'Immunologie de Marseille-Luminy, Marseille, France
| | - Marie-Claire Phelipot
- Aix Marseille Univ, CNRS, INSERM, CIML, Centre d'Immunologie de Marseille-Luminy, Marseille, France
| | - Audrey Salles
- Aix Marseille Univ, CNRS, INSERM, CIML, Centre d'Immunologie de Marseille-Luminy, Marseille, France.,UTechS Photonic BioImaging (Imagopole) Citech, Institut Pasteur, Paris, 75724, France
| | - Elise Bergot
- Aix Marseille Univ, CNRS, INSERM, CIML, Centre d'Immunologie de Marseille-Luminy, Marseille, France
| | - Ambroise Wu
- Aix Marseille Univ, CNRS, INSERM, CIML, Centre d'Immunologie de Marseille-Luminy, Marseille, France
| | - Gaëtan Chicanne
- Institut des Maladies Métaboliques et Cardiovasculaires, Inserm U1048, Université Toulouse 3, Toulouse, France
| | - Mathieu Fallet
- Aix Marseille Univ, CNRS, INSERM, CIML, Centre d'Immunologie de Marseille-Luminy, Marseille, France
| | - Sophie Brustlein
- Aix Marseille Univ, CNRS, INSERM, CIML, Centre d'Immunologie de Marseille-Luminy, Marseille, France
| | - Cyrille Billaudeau
- Aix Marseille Univ, CNRS, INSERM, CIML, Centre d'Immunologie de Marseille-Luminy, Marseille, France.,Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350, Jouy-en-Josas, France
| | - Anthony Formisano
- Aix Marseille Univ, CNRS, INSERM, CIML, Centre d'Immunologie de Marseille-Luminy, Marseille, France
| | - Sébastien Mailfert
- Aix Marseille Univ, CNRS, INSERM, CIML, Centre d'Immunologie de Marseille-Luminy, Marseille, France
| | - Bernard Payrastre
- Institut des Maladies Métaboliques et Cardiovasculaires, Inserm U1048, Université Toulouse 3, Toulouse, France.,Laboratoire d'Hématologie, Centre Hospitalier Universitaire de Toulouse, Toulouse, France
| | - Didier Marguet
- Aix Marseille Univ, CNRS, INSERM, CIML, Centre d'Immunologie de Marseille-Luminy, Marseille, France
| | - Sophie Brasselet
- Aix-Marseille Univ, CNRS, Centrale Marseille, Institut Fresnel, UMR 7249, 13397, Marseille, France
| | - Yannick Hamon
- Aix Marseille Univ, CNRS, INSERM, CIML, Centre d'Immunologie de Marseille-Luminy, Marseille, France.
| | - Hai-Tao He
- Aix Marseille Univ, CNRS, INSERM, CIML, Centre d'Immunologie de Marseille-Luminy, Marseille, France.
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14
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Min B. Spontaneous T Cell Proliferation: A Physiologic Process to Create and Maintain Homeostatic Balance and Diversity of the Immune System. Front Immunol 2018; 9:547. [PMID: 29616038 PMCID: PMC5868360 DOI: 10.3389/fimmu.2018.00547] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2018] [Accepted: 03/05/2018] [Indexed: 11/14/2022] Open
Abstract
Naive T lymphocytes undergo heterogeneous proliferative responses when introduced into lymphopenic hosts, referred to as “homeostatic proliferation” and “spontaneous proliferation.” Spontaneous proliferation is a unique process through which the immune system generates memory phenotype cells with increasing T cell receptors repertoire complexity. Here, the mechanisms that initiate and control spontaneous proliferation are discussed.
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Affiliation(s)
- Booki Min
- Department of Immunology, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, United States
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15
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Zheng L, Li J, Lenardo M. Restimulation-induced cell death: new medical and research perspectives. Immunol Rev 2018; 277:44-60. [PMID: 28462523 DOI: 10.1111/imr.12535] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
In the periphery, homeostasis of the immune system depends on the equilibrium of expanding and contracting T lymphocytes during immune response. An important mechanism of lymphocyte contraction is clonal depletion of activated T cells by cytokine withdrawal induced death (CWID) and TCR restimulation induced cell death (RICD). Deficiencies in signaling components for CWID and RICD leads to autoimmunune lymphoproliferative disorders in mouse and human. The most important feature of CWID and RICD is clonal specificity, which lends great appeal as a strategy for targeted tolerance induction and treatment of autoimmune diseases, allergic disorders, and graft rejection by depleting undesired disease-causing T cells while keeping the overall host immunity intact.
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Affiliation(s)
- Lixin Zheng
- Laboratory of Immunology and Clinical Genomics Program, Molecular Development of the Immune System Section, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Jian Li
- Laboratory of Immunology and Clinical Genomics Program, Molecular Development of the Immune System Section, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA.,Institute of Immunology, Third Military Medical University, Chongqing, China
| | - Michael Lenardo
- Laboratory of Immunology and Clinical Genomics Program, Molecular Development of the Immune System Section, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
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16
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Guichard V, Bonilla N, Durand A, Audemard-Verger A, Guilbert T, Martin B, Lucas B, Auffray C. Calcium-mediated shaping of naive CD4 T-cell phenotype and function. eLife 2017; 6:27215. [PMID: 29239722 PMCID: PMC5747519 DOI: 10.7554/elife.27215] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 11/23/2017] [Indexed: 12/11/2022] Open
Abstract
Continuous contact with self-major histocompatibility complex ligands is essential for the survival of naive CD4 T cells. We have previously shown that the resulting tonic TCR signaling also influences their fate upon activation by increasing their ability to differentiate into induced/peripheral regulatory T cells. To decipher the molecular mechanisms governing this process, we here focus on the TCR signaling cascade and demonstrate that a rise in intracellular calcium levels is sufficient to modulate the phenotype of mouse naive CD4 T cells and to increase their sensitivity to regulatory T-cell polarization signals, both processes relying on calcineurin activation. Accordingly, in vivo calcineurin inhibition leads the most self-reactive naive CD4 T cells to adopt the phenotype of their less self-reactive cell-counterparts. Collectively, our findings demonstrate that calcium-mediated activation of the calcineurin pathway acts as a rheostat to shape both the phenotype and effector potential of naive CD4 T cells in the steady-state. To help protect the body from disease, small immune cells called T lymphocytes move rapidly, searching for signs of infection. These signs are antigens – processed pieces of proteins from invading microbes – that are displayed on the surface of so-called antigen-presenting cells.Before it encounters its specific antigen, a T cell is called naive. After encountering its antigen, the naive T cell activates and then develops into a variety of immune cells, each with a specific activity. These immune cells include so-called peripherally induced regulatory T cells (or “pTreg cells” for short), which, as the name suggests, help to regulate the immune response. In addition to foreign antigens from microbes, antigen-presenting cells display fragments of the body’s own proteins too. All naive T cells recognize some “Self-antigens”, but not as strongly as they recognize foreign antigens. As a naive T cell travels around the body, it repeatedly interacts with antigen-presenting cells that display Self-antigens, which triggers a low level of signaling in the T cell. While this background signaling was known to help the T cell survive, in 2013, researchers reported that: it also makes the T cell more responsive to foreign antigens; and it shapes how these cells will respond when activated. For example, the naive T cells that respond the most to Self-antigens were seen to be much more likely to become pTreg cells when activated than other T cells. Guichard et al. – who include several of the researchers involved in the 2013 work – set out to understand why the most Self-reactive T cells show this bias toward becoming pTreg cells. The experiments used a range of approaches with T cells both in the laboratory and in mice. By looking at which genes were active in the most Self-reactive T cells, Guichard et al. narrowed in on a signaling pathway that involves calcium ions and an enzyme called Calcineurin. Blocking this pathway caused the most Self-reactive T cells to lose their bias, and instead develop in the same way as the least Self-reactive T cells. Guichard et al. propose that the continuous interactions with Self-antigens trigger waves of calcium ions in a naive T cell that shapes its behavior and future development. In a related study, Dong, Othy et al. also conclude that contact with antigen-presenting cells causes calcium signals that shape how the T cells behave. In addition to providing more detail about the inner workings of immune cells, these findings may also have implications in a clinical setting. Calcineurin inhibitors are often used to suppress the immune system in transplant patients to prevent rejection of the transplanted organ. However, it has proved difficult to safely interrupt these therapies even after many years. These new findings may provide a possible explanation for this, by suggesting that the inhibitors may also interfere with the generation of pTreg cells. Without these cells’ regulatory influence, the immune system is unlikely to ever become tolerant of the transplant.
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Affiliation(s)
- Vincent Guichard
- Institut Cochin, Paris Descartes Université, CNRS UMR8104, INSERM U1016, Paris, France.,Paris Diderot Université, Paris, France
| | - Nelly Bonilla
- Institut Cochin, Paris Descartes Université, CNRS UMR8104, INSERM U1016, Paris, France
| | - Aurélie Durand
- Institut Cochin, Paris Descartes Université, CNRS UMR8104, INSERM U1016, Paris, France
| | | | - Thomas Guilbert
- Institut Cochin, Paris Descartes Université, CNRS UMR8104, INSERM U1016, Paris, France
| | - Bruno Martin
- Institut Cochin, Paris Descartes Université, CNRS UMR8104, INSERM U1016, Paris, France
| | - Bruno Lucas
- Institut Cochin, Paris Descartes Université, CNRS UMR8104, INSERM U1016, Paris, France
| | - Cédric Auffray
- Institut Cochin, Paris Descartes Université, CNRS UMR8104, INSERM U1016, Paris, France
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17
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Holt MP, Punkosdy GA, Glass DD, Shevach EM. TCR Signaling and CD28/CTLA-4 Signaling Cooperatively Modulate T Regulatory Cell Homeostasis. THE JOURNAL OF IMMUNOLOGY 2017; 198:1503-1511. [PMID: 28053234 DOI: 10.4049/jimmunol.1601670] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Accepted: 12/04/2016] [Indexed: 12/16/2022]
Abstract
Foxp3+ T regulatory cells (Tregs), conventional CD4+Foxp3- T cells, and CD8+ T cells represent heterogeneous populations composed of naive phenotype (NP, CD44low) and memory phenotype (MP, CD44high) subpopulations. NP and MP subsets differ in their activation state, contribution to immune function, and capacity to proliferate in vivo. To further understand the factors that contribute to the differential homeostasis of NP/MP subsets, we examined the differential effects of CD28 and CTLA-4 interaction with CD80/CD86, as well as MHC class II-TCR interaction within mouse Treg pools and CD4+ and CD8+ T cell pools. Blockade of CD80/CD86 with CTLA-4-Ig markedly reduced the cycling and absolute numbers of MP Tregs and MP CD4+ T cells, with minimal effect on the NP T cell subpopulations. Blockade of MHC class II-TCR interaction led to selective expansion of MP Tregs and MP CD4+ and CD8+ T cells that was reversed upon cotreatment with CTLA-4-Ig. Treatment with anti-CTLA-4 mAb altered MP Treg and MP CD4+ and CD8+ T cell homeostasis in a manner similar to that observed with anti-MHC class II. We postulate a complex pathway in which CD28 is the primary driver of Treg proliferation and CTLA-4 functions as the main brake but is likely dependent on TCR signals and CD80/CD86. These findings have important implications for the use of biologic agents targeting such pathways to modulate autoimmune and neoplastic disease.
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Affiliation(s)
- Michael P Holt
- Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892
| | - George A Punkosdy
- Emory Vaccine Center, Emory University School of Medicine, Atlanta, GA 30322; and.,Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, GA 30322
| | - Deborah D Glass
- Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Ethan M Shevach
- Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892;
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18
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Kamimura D, Arima Y, Tsuruoka M, Jiang JJ, Bando H, Meng J, Sabharwal L, Stofkova A, Nishikawa N, Higuchi K, Ogura H, Atsumi T, Murakami M. Strong TCR-mediated signals suppress integrated stress responses induced by KDELR1 deficiency in naive T cells. Int Immunol 2015; 28:117-26. [PMID: 26489882 DOI: 10.1093/intimm/dxv059] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Accepted: 10/09/2015] [Indexed: 12/17/2022] Open
Abstract
KDEL receptor 1 (KDELR1) regulates integrated stress responses (ISR) to promote naive T-cell survival in vivo. In a mouse line having nonfunctional KDELR1, T-Red (naive T-cell reduced) mice, polyclonal naive T cells show excessive ISR and eventually undergo apoptosis. However, breeding T-Red mice with TCR-transgenic mice bearing relatively high TCR affinity rescued the T-Red phenotype, implying a link between ISR-induced apoptosis and TCR-mediated signaling. Here, we showed that strong TCR stimulation reduces ISR in naive T cells. In mice lacking functional KDELR1, surviving naive T cells expressed significantly higher levels of CD5, a surrogate marker of TCR self-reactivity. In addition, higher TCR affinity/avidity was confirmed using a tetramer dissociation assay on the surviving naive T cells, suggesting that among the naive T-cell repertoire, those that receive relatively stronger TCR-mediated signals via self-antigens survive enhanced ISR. Consistent with this observation, weak TCR stimulation with altered peptide ligands decreased the survival and proliferation of naive T cells, whereas stimulation with ligands having higher affinity had no such effect. These results suggest a novel role of TCR-mediated signals in the attenuation of ISR in vivo.
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Affiliation(s)
- Daisuke Kamimura
- Division of Molecular Neuroimmunology, Institute for Genetic Medicine and Graduate School of Medicine, Hokkaido University, Kita-15, Nishi-7, Kita-Ku, Sapporo, Hokkaido 060-0815, Japan Laboratory of Developmental Immunology, Graduate School of Frontier Biosciences, Graduate School of Medicine and WPI Immunology Frontier Research Center, Osaka University, Suita, Osaka 565-0871, Japan
| | - Yasunobu Arima
- Division of Molecular Neuroimmunology, Institute for Genetic Medicine and Graduate School of Medicine, Hokkaido University, Kita-15, Nishi-7, Kita-Ku, Sapporo, Hokkaido 060-0815, Japan Laboratory of Developmental Immunology, Graduate School of Frontier Biosciences, Graduate School of Medicine and WPI Immunology Frontier Research Center, Osaka University, Suita, Osaka 565-0871, Japan
| | - Mineko Tsuruoka
- Laboratory of Developmental Immunology, Graduate School of Frontier Biosciences, Graduate School of Medicine and WPI Immunology Frontier Research Center, Osaka University, Suita, Osaka 565-0871, Japan
| | - Jing-Jing Jiang
- Division of Molecular Neuroimmunology, Institute for Genetic Medicine and Graduate School of Medicine, Hokkaido University, Kita-15, Nishi-7, Kita-Ku, Sapporo, Hokkaido 060-0815, Japan Laboratory of Developmental Immunology, Graduate School of Frontier Biosciences, Graduate School of Medicine and WPI Immunology Frontier Research Center, Osaka University, Suita, Osaka 565-0871, Japan
| | - Hidenori Bando
- Division of Molecular Neuroimmunology, Institute for Genetic Medicine and Graduate School of Medicine, Hokkaido University, Kita-15, Nishi-7, Kita-Ku, Sapporo, Hokkaido 060-0815, Japan Laboratory of Developmental Immunology, Graduate School of Frontier Biosciences, Graduate School of Medicine and WPI Immunology Frontier Research Center, Osaka University, Suita, Osaka 565-0871, Japan
| | - Jie Meng
- Division of Molecular Neuroimmunology, Institute for Genetic Medicine and Graduate School of Medicine, Hokkaido University, Kita-15, Nishi-7, Kita-Ku, Sapporo, Hokkaido 060-0815, Japan Laboratory of Developmental Immunology, Graduate School of Frontier Biosciences, Graduate School of Medicine and WPI Immunology Frontier Research Center, Osaka University, Suita, Osaka 565-0871, Japan
| | - Lavannya Sabharwal
- Division of Molecular Neuroimmunology, Institute for Genetic Medicine and Graduate School of Medicine, Hokkaido University, Kita-15, Nishi-7, Kita-Ku, Sapporo, Hokkaido 060-0815, Japan Laboratory of Developmental Immunology, Graduate School of Frontier Biosciences, Graduate School of Medicine and WPI Immunology Frontier Research Center, Osaka University, Suita, Osaka 565-0871, Japan
| | - Andrea Stofkova
- Division of Molecular Neuroimmunology, Institute for Genetic Medicine and Graduate School of Medicine, Hokkaido University, Kita-15, Nishi-7, Kita-Ku, Sapporo, Hokkaido 060-0815, Japan
| | - Naoki Nishikawa
- Division of Molecular Neuroimmunology, Institute for Genetic Medicine and Graduate School of Medicine, Hokkaido University, Kita-15, Nishi-7, Kita-Ku, Sapporo, Hokkaido 060-0815, Japan
| | - Kotaro Higuchi
- Division of Molecular Neuroimmunology, Institute for Genetic Medicine and Graduate School of Medicine, Hokkaido University, Kita-15, Nishi-7, Kita-Ku, Sapporo, Hokkaido 060-0815, Japan
| | - Hideki Ogura
- Division of Molecular Neuroimmunology, Institute for Genetic Medicine and Graduate School of Medicine, Hokkaido University, Kita-15, Nishi-7, Kita-Ku, Sapporo, Hokkaido 060-0815, Japan Laboratory of Developmental Immunology, Graduate School of Frontier Biosciences, Graduate School of Medicine and WPI Immunology Frontier Research Center, Osaka University, Suita, Osaka 565-0871, Japan
| | - Toru Atsumi
- Division of Molecular Neuroimmunology, Institute for Genetic Medicine and Graduate School of Medicine, Hokkaido University, Kita-15, Nishi-7, Kita-Ku, Sapporo, Hokkaido 060-0815, Japan Laboratory of Developmental Immunology, Graduate School of Frontier Biosciences, Graduate School of Medicine and WPI Immunology Frontier Research Center, Osaka University, Suita, Osaka 565-0871, Japan
| | - Masaaki Murakami
- Division of Molecular Neuroimmunology, Institute for Genetic Medicine and Graduate School of Medicine, Hokkaido University, Kita-15, Nishi-7, Kita-Ku, Sapporo, Hokkaido 060-0815, Japan Laboratory of Developmental Immunology, Graduate School of Frontier Biosciences, Graduate School of Medicine and WPI Immunology Frontier Research Center, Osaka University, Suita, Osaka 565-0871, Japan
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19
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Brazin KN, Mallis RJ, Das DK, Feng Y, Hwang W, Wang JH, Wagner G, Lang MJ, Reinherz EL. Structural Features of the αβTCR Mechanotransduction Apparatus That Promote pMHC Discrimination. Front Immunol 2015; 6:441. [PMID: 26388869 PMCID: PMC4558533 DOI: 10.3389/fimmu.2015.00441] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Accepted: 08/14/2015] [Indexed: 12/20/2022] Open
Abstract
The αβTCR was recently revealed to function as a mechanoreceptor. That is, it leverages mechanical energy generated during immune surveillance and at the immunological synapse to drive biochemical signaling following ligation by a specific foreign peptide-MHC complex (pMHC). Here, we review the structural features that optimize this transmembrane (TM) receptor for mechanotransduction. Specialized adaptations include (1) the CβFG loop region positioned between Vβ and Cβ domains that allosterically gates both dynamic T cell receptor (TCR)-pMHC bond formation and lifetime; (2) the rigid super β-sheet amalgams of heterodimeric CD3εγ and CD3εδ ectodomain components of the αβTCR complex; (3) the αβTCR subunit connecting peptides linking the extracellular and TM segments, particularly the oxidized CxxC motif in each CD3 heterodimeric subunit that facilitates force transfer through the TM segments and surrounding lipid, impacting cytoplasmic tail conformation; and (4) quaternary changes in the αβTCR complex that accompany pMHC ligation under load. How bioforces foster specific αβTCR-based pMHC discrimination and why dynamic bond formation is a primary basis for kinetic proofreading are discussed. We suggest that the details of the molecular rearrangements of individual αβTCR subunit components can be analyzed utilizing a combination of structural biology, single-molecule FRET, optical tweezers, and nanobiology, guided by insightful atomistic molecular dynamic studies. Finally, we review very recent data showing that the pre-TCR complex employs a similar mechanobiology to that of the αβTCR to interact with self-pMHC ligands, impacting early thymic repertoire selection prior to the CD4(+)CD8(+) double positive thymocyte stage of development.
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Affiliation(s)
- Kristine N. Brazin
- Laboratory of Immunobiology, Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
- Department of Medicine, Harvard Medical School, Boston, MA, USA
| | - Robert J. Mallis
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
| | - Dibyendu Kumar Das
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN, USA
| | - Yinnian Feng
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN, USA
| | - Wonmuk Hwang
- Department of Biomedical Engineering, Texas A&M University, College Station, TX, USA
- Department of Materials Science and Engineering, Texas A&M University, College Station, TX, USA
- School of Computational Sciences, Korea Institute for Advanced Study, Seoul, South Korea
| | - Jia-huai Wang
- Laboratory of Immunobiology, Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
- Department of Medicine, Harvard Medical School, Boston, MA, USA
- Department of Pediatrics, Harvard Medical School, Boston, MA, USA
| | - Gerhard Wagner
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
| | - Matthew J. Lang
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN, USA
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, USA
| | - Ellis L. Reinherz
- Laboratory of Immunobiology, Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
- Department of Medicine, Harvard Medical School, Boston, MA, USA
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20
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Wu W, Yan C, Shi X, Li L, Liu W, Xu C. Lipid in T-cell receptor transmembrane signaling. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2015; 118:130-8. [DOI: 10.1016/j.pbiomolbio.2015.04.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2015] [Revised: 04/20/2015] [Accepted: 04/22/2015] [Indexed: 12/18/2022]
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21
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Muro R, Nitta T, Okada T, Ideta H, Tsubata T, Suzuki H. The Ras GTPase-activating protein Rasal3 supports survival of naive T cells. PLoS One 2015; 10:e0119898. [PMID: 25793935 PMCID: PMC4368693 DOI: 10.1371/journal.pone.0119898] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Accepted: 01/16/2015] [Indexed: 11/19/2022] Open
Abstract
The Ras-mitogen-activated protein kinase (MAPK) pathway is crucial for T cell receptor (TCR) signaling in the development and function of T cells. The significance of various modulators of the Ras-MAPK pathway in T cells, however, remains to be fully understood. Ras-activating protein-like 3 (Rasal3) is an uncharacterized member of the SynGAP family that contains a conserved Ras GTPase-activating protein (GAP) domain, and is predominantly expressed in the T cell lineage. In the current study, we investigated the function and physiological roles of Rasal3. Our results showed that Rasal3 possesses RasGAP activity, but not Rap1GAP activity, and represses TCR-stimulated ERK phosphorylation in a T cell line. In systemic Rasal3-deficient mice, T cell development in the thymus including positive selection, negative selection, and β-selection was unaffected. However, the number of naive, but not effector memory CD4 and CD8 T cell in the periphery was significantly reduced in Rasal3-deficient mice, and associated with a marked increase in apoptosis of these cells. Indeed, survival of Rasal3 deficient naive CD4 T cells in vivo by adoptive transfer was significantly impaired, whereas IL-7-dependent survival of naive CD4 T cells in vitro was unaltered. Collectively, Rasal3 is required for in vivo survival of peripheral naive T cells, contributing to the maintenance of optimal T cell numbers.
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Affiliation(s)
- Ryunosuke Muro
- Department of Immunology and Pathology, Research Institute, National Center for Global Health and Medicine, Ichikawa-shi, Chiba, Japan
- Department of Immunology, Medical Research Institute, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan
| | - Takeshi Nitta
- Department of Immunology and Pathology, Research Institute, National Center for Global Health and Medicine, Ichikawa-shi, Chiba, Japan
| | - Toshiyuki Okada
- Department of Immunology and Pathology, Research Institute, National Center for Global Health and Medicine, Ichikawa-shi, Chiba, Japan
| | - Hitoshi Ideta
- Department of Immunology and Pathology, Research Institute, National Center for Global Health and Medicine, Ichikawa-shi, Chiba, Japan
| | - Takeshi Tsubata
- Department of Immunology, Medical Research Institute, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan
| | - Harumi Suzuki
- Department of Immunology and Pathology, Research Institute, National Center for Global Health and Medicine, Ichikawa-shi, Chiba, Japan
- * E-mail:
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22
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Rodriguez SN, Jiang M, Bujo H, Allen PM. Self-pMHCII complexes are variably expressed in the thymus and periphery independent of mRNA expression but dependent on the activation state of the APCs. Mol Immunol 2015; 63:428-36. [PMID: 25451972 PMCID: PMC4254551 DOI: 10.1016/j.molimm.2014.09.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Revised: 09/24/2014] [Accepted: 09/25/2014] [Indexed: 11/23/2022]
Abstract
Self-peptide MHCII ligands are critical for selection of CD4+ T cells in the thymus, and maintenance in the periphery. To date, no investigation as to the exact thymic and peripheral expression of a naturally occurring positive selecting self-peptide MHCII (self-pMHCII) complex has taken place. We have generated a sensitive T cell hybridoma to functionally detect the endogenous presentation of a confirmed positive selecting self-pMHCII complex for a CD4+ transgenic T cell. Using this tool to survey and quantify the expression selecting of self-pMHCII, we have shown unequivocal proof that a known CD4+ selecting ligand can be presented on both positive and negative selecting thymic APCs. We also show that peripheral presentation of this same selecting ligand is affected by the activation state of the APCs. Furthermore, discrepancies between the gene expression and self-pMHCII complex presentation of this bona fide selecting ligand suggest that functional detection self-ligand complexes will be required to establish a complete view of the naturally presented endogenous self-pMHC landscape.
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Affiliation(s)
- Stephanie N Rodriguez
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, United States
| | - Meizi Jiang
- Department of Clinical-Laboratory and Experimental-Research Medicine, Toho University, Sakura Medical Center, Sakura, Japan
| | - Hideaki Bujo
- Department of Clinical-Laboratory and Experimental-Research Medicine, Toho University, Sakura Medical Center, Sakura, Japan
| | - Paul M Allen
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, United States.
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23
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Insights into the initiation of TCR signaling. Nat Immunol 2014; 15:798-807. [PMID: 25137454 DOI: 10.1038/ni.2940] [Citation(s) in RCA: 257] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2014] [Accepted: 06/10/2014] [Indexed: 12/13/2022]
Abstract
The initiation of T cell antigen receptor signaling is a key step that can result in T cell activation and the orchestration of an adaptive immune response. Early events in T cell receptor signaling can distinguish between agonist and endogenous ligands with exquisite selectivity, and show extraordinary sensitivity to minute numbers of agonists in a sea of endogenous ligands. We review our current knowledge of models and crucial molecules that aim to provide a mechanistic explanation for these observations. Building on current understanding and a discussion of unresolved issues, we propose a molecular model for initiation of T cell receptor signaling that may serve as a useful guide for future studies.
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24
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Fulton RB, Hamilton SE, Xing Y, Best JA, Goldrath AW, Hogquist KA, Jameson SC. The TCR's sensitivity to self peptide-MHC dictates the ability of naive CD8(+) T cells to respond to foreign antigens. Nat Immunol 2014; 16:107-17. [PMID: 25419629 PMCID: PMC4270846 DOI: 10.1038/ni.3043] [Citation(s) in RCA: 148] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Accepted: 10/27/2014] [Indexed: 12/13/2022]
Abstract
The strength of self-peptide–major histocompatibility complex (MHC)
recognition dictates naïve CD8+ T cell homeostasis, but its
effect on foreign antigen reactivity is controversial. As CD5 expression correlates with
self-recognition, we studied CD5lo and CD5hi naïve
CD8+ T cells. Gene expression characteristics suggested
CD5hi cells were better poised for reactivity and differentiation compared to
the CD5lo population, and we found that the CD5hi pool exhibited
more efficient clonal recruitment and expansion, as well as enhanced reactivity to
inflammatory cues, during recognition of foreign antigen. Yet foreign peptide–MHC
recognition was similar for both subsets. Thus, CD8+ T cells with
higher self-reactivity dominate the immune response against foreign antigens, with
implications for T cell repertoire diversity and autoimmunity.
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Affiliation(s)
- Ross B Fulton
- Department of Laboratory Medicine and Pathology, Center for Immunology, University of Minnesota Medical School, Minneapolis, Minnesota, USA
| | - Sara E Hamilton
- Department of Laboratory Medicine and Pathology, Center for Immunology, University of Minnesota Medical School, Minneapolis, Minnesota, USA
| | - Yan Xing
- Department of Laboratory Medicine and Pathology, Center for Immunology, University of Minnesota Medical School, Minneapolis, Minnesota, USA
| | - J Adam Best
- Division of Biological Sciences, University of California San Diego, La Jolla, California, USA
| | - Ananda W Goldrath
- Division of Biological Sciences, University of California San Diego, La Jolla, California, USA
| | - Kristin A Hogquist
- Department of Laboratory Medicine and Pathology, Center for Immunology, University of Minnesota Medical School, Minneapolis, Minnesota, USA
| | - Stephen C Jameson
- Department of Laboratory Medicine and Pathology, Center for Immunology, University of Minnesota Medical School, Minneapolis, Minnesota, USA
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25
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Delpoux A, Yakonowsky P, Durand A, Charvet C, Valente M, Pommier A, Bonilla N, Martin B, Auffray C, Lucas B. TCR signaling events are required for maintaining CD4 regulatory T cell numbers and suppressive capacities in the periphery. THE JOURNAL OF IMMUNOLOGY 2014; 193:5914-23. [PMID: 25381435 DOI: 10.4049/jimmunol.1400477] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
CD4 regulatory T cells (Tregs) can be subdivided into two subsets according to Ly-6C expression in the periphery. Phenotypic analysis, imaging, and adoptive-transfer experiments of peripheral Ly-6C(-) and Ly-6C(+) Tregs reveal that the nonexpression of Ly-6C by ∼70% of peripheral Tregs depends on TCR signaling events. Interestingly, Ly-6C(-) Tregs express higher surface amounts of key immunosuppressive molecules than do Ly-6C(+) Tregs and produce constitutively anti-inflammatory cytokines. In line with their phenotype, Ly-6C(+) Tregs exhibit poor suppressive capacities in vitro and in vivo. Finally, although Ly-6C(-) Tregs maintain their numbers with age, Ly-6C(+) Tregs gradually disappear. Altogether, our data strongly suggest that both the survival and suppressive functions of peripheral CD4 Tregs rely on their ability to receive strong TCR signals.
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Affiliation(s)
- Arnaud Delpoux
- Institut Cochin, Centre National de la Recherche Scientifique UMR8104, INSERM U1016, Université Paris Descartes, 75014 Paris, France
| | - Philippe Yakonowsky
- Institut Cochin, Centre National de la Recherche Scientifique UMR8104, INSERM U1016, Université Paris Descartes, 75014 Paris, France
| | - Aurélie Durand
- Institut Cochin, Centre National de la Recherche Scientifique UMR8104, INSERM U1016, Université Paris Descartes, 75014 Paris, France
| | - Céline Charvet
- Institut Cochin, Centre National de la Recherche Scientifique UMR8104, INSERM U1016, Université Paris Descartes, 75014 Paris, France
| | - Michael Valente
- Institut Cochin, Centre National de la Recherche Scientifique UMR8104, INSERM U1016, Université Paris Descartes, 75014 Paris, France
| | - Arnaud Pommier
- Institut Cochin, Centre National de la Recherche Scientifique UMR8104, INSERM U1016, Université Paris Descartes, 75014 Paris, France
| | - Nelly Bonilla
- Institut Cochin, Centre National de la Recherche Scientifique UMR8104, INSERM U1016, Université Paris Descartes, 75014 Paris, France
| | - Bruno Martin
- Institut Cochin, Centre National de la Recherche Scientifique UMR8104, INSERM U1016, Université Paris Descartes, 75014 Paris, France
| | - Cédric Auffray
- Institut Cochin, Centre National de la Recherche Scientifique UMR8104, INSERM U1016, Université Paris Descartes, 75014 Paris, France
| | - Bruno Lucas
- Institut Cochin, Centre National de la Recherche Scientifique UMR8104, INSERM U1016, Université Paris Descartes, 75014 Paris, France
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26
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Hogquist KA, Jameson SC. The self-obsession of T cells: how TCR signaling thresholds affect fate 'decisions' and effector function. Nat Immunol 2014; 15:815-23. [PMID: 25137456 PMCID: PMC4348363 DOI: 10.1038/ni.2938] [Citation(s) in RCA: 196] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2014] [Accepted: 06/02/2014] [Indexed: 12/11/2022]
Abstract
Self-reactivity was once seen as a potential characteristic of T cells that was eliminated by clonal selection to protect the host from autoimmune pathology. It is now understood that the T cell repertoire is in fact broadly self-reactive, even self-centered. The strength with which a T cell reacts to self ligands and the environmental context in which this reaction occurs influence almost every aspect of T cell biology, from development to differentiation to effector function. Here we highlight recent advances and discoveries that relate to T cell self-reactivity, with a particular emphasis on T cell antigen receptor (TCR) signaling thresholds.
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Affiliation(s)
- Kristin A Hogquist
- Center for Immunology and Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, Minnesota, USA
| | - Stephen C Jameson
- Center for Immunology and Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, Minnesota, USA
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27
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Opata MM, Stephens R. Early Decision: Effector and Effector Memory T Cell Differentiation in Chronic Infection. ACTA ACUST UNITED AC 2014; 9:190-206. [PMID: 24790593 PMCID: PMC4000274 DOI: 10.2174/1573395509666131126231209] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Revised: 11/08/2013] [Accepted: 11/19/2013] [Indexed: 11/22/2022]
Abstract
As effector memory T cells (Tem) are the predominant population elicited by chronic parasitic infections,
increasing our knowledge of their function, survival and derivation, as phenotypically and functionally distinct from
central memory and effector T cells will be critical to vaccine development for these diseases. In some infections, memory
T cells maintain increased effector functions, however; this may require the presence of continued antigen, which can also
lead to T cell exhaustion. Alternatively, in the absence of antigen, only the increase in the number of memory cells
remains, without enhanced functionality as central memory. In order to understand the requirement for antigen and the
potential for longevity or protection, the derivation of each type of memory must be understood. A thorough review of the
data establishes the existence of both memory (Tmem) precursors and effector T cells (Teff) from the first hours of an
immune response. This suggests a new paradigm of Tmem differentiation distinct from the proposition that Tmem only
appear after the contraction of Teff. Several signals have been shown to be important in the generation of memory T cells,
such as the integrated strength of “signals 1-3” of antigen presentation (antigen receptor, co-stimulation, cytokines) as
perceived by each T cell clone. Given that these signals integrated at antigen presentation cells have been shown to
determine the outcome of Teff and Tmem phenotypes and numbers, this decision must be made at a very early stage. It
would appear that the overwhelming expansion of effector T cells and the inability to phenotypically distinguish memory
T cells at early time points has masked this important decision point. This does not rule out an effect of repeated
stimulation or chronic inflammatory milieu on populations generated in these early stages. Recent studies suggest that
Tmem are derived from early Teff, and we suggest that this includes Tem as well as Tcm. Therefore, we propose a
testable model for the pathway of differentiation from naïve to memory that suggests that Tem are not fully differentiated
effector cells, but derived from central memory T cells as originally suggested by Sallusto et al. in 1999, but much
debated since.
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Affiliation(s)
- Michael M Opata
- University of Texas Medical Branch, Department of Internal Medicine, Division of Infectious Disease, 300 University Avenue, Galveston, TX 77555-0435, USA
| | - Robin Stephens
- University of Texas Medical Branch, Department of Internal Medicine, Division of Infectious Disease, 300 University Avenue, Galveston, TX 77555-0435, USA
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28
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Highly self-reactive naive CD4 T cells are prone to differentiate into regulatory T cells. Nat Commun 2013; 4:2209. [DOI: 10.1038/ncomms3209] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2013] [Accepted: 06/26/2013] [Indexed: 02/06/2023] Open
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29
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Hancock DG, Guy TV, Shklovskaya E, Fazekas de St Groth B. Experimental models to investigate the function of dendritic cell subsets: challenges and implications. Clin Exp Immunol 2013; 171:147-54. [PMID: 23286941 DOI: 10.1111/cei.12027] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/25/2012] [Indexed: 11/29/2022] Open
Abstract
The dendritic cell (DC) lineage is remarkably heterogeneous. It has been postulated that specialized DC subsets have evolved in order to select and support the multitude of possible T cell differentiation pathways. However, defining the function of individual DC subsets has proven remarkably difficult, and DC subset control of key T cell fates such as tolerance, T helper cell commitment and regulatory T cell induction is still not well understood. While the difficulty in assigning unique functions to particular DC subsets may be due to sharing of functions, it may also reflect a lack of appropriate physiological in-vivo models for studying DC function. In this paper we review the limitations associated with many of the current DC models and highlight some of the underlying difficulties involved in studying the function of murine DC subsets.
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Affiliation(s)
- D G Hancock
- Centenary Institute of Cancer Medicine and Cell Biology and the Discipline of Dermatology, University of Sydney, Sydney, NSW, Australia
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30
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Mandl JN, Monteiro JP, Vrisekoop N, Germain RN. T cell-positive selection uses self-ligand binding strength to optimize repertoire recognition of foreign antigens. Immunity 2013; 38:263-274. [PMID: 23290521 PMCID: PMC3785078 DOI: 10.1016/j.immuni.2012.09.011] [Citation(s) in RCA: 226] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2012] [Accepted: 09/28/2012] [Indexed: 01/19/2023]
Abstract
Developing T cells express diverse antigen receptors whose specificities are not prematched to the foreign antigens they eventually encounter. Past experiments have revealed that thymocytes must productively signal in response to self antigens to mature and enter the peripheral T cell pool (positive selection), but how this process enhances effective mature T cell responses to foreign antigen is not fully understood. Here we have documented an unsuspected connection between thymic recognition events and foreign antigen-driven T cell responses. We find that the strength of self-reactivity is a clone-specific property unexpectedly directly related to the strength of T cell receptor (TCR) binding to presented foreign antigen. T cells with receptors showing stronger interaction with self dominate in responses to infections and accumulate in aging individuals, revealing that positive selection contributes to effective immunity by skewing the mature TCR repertoire toward highly effective recognition of pathogens that pose a danger to the host.
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Affiliation(s)
- Judith N. Mandl
- Lymphocyte Biology Section, Laboratory of Systems Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892 USA
| | - João P. Monteiro
- Lymphocyte Biology Section, Laboratory of Systems Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892 USA
| | - Nienke Vrisekoop
- Lymphocyte Biology Section, Laboratory of Systems Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892 USA
| | - Ronald N. Germain
- Lymphocyte Biology Section, Laboratory of Systems Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892 USA
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31
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Singh NJ, Bando JK, Schwartz RH. Subsets of nonclonal neighboring CD4+ T cells specifically regulate the frequency of individual antigen-reactive T cells. Immunity 2012; 37:735-46. [PMID: 23021952 PMCID: PMC3478444 DOI: 10.1016/j.immuni.2012.08.008] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2012] [Revised: 05/26/2012] [Accepted: 08/13/2012] [Indexed: 10/27/2022]
Abstract
After an immune response, the expanded population of antigen-specific CD4(+) T cells contract to steady state levels. We have found that the contraction is neither cell-autonomous nor mediated by competition for generic trophic factors, but regulated by relatively rare subsets of neighboring CD4(+) T cells not necessarily of a conventional regulatory T cell lineage. These regulators, referred to as deletors, specifically limit the frequency of particular antigen-specific T cells even though they are not reactive to the same agonist as their targets. Instead, an isolated deletor could outcompete the target for recognition of a shared, nonstimulatory endogenous peptide-MHC ligand. This mechanism was sufficient to prevent even agonist-driven autoimmune disease in a lymphopenic environment. Such a targeted regulation of homeostasis within narrow colonies of T cells with related TCR specificities for subthreshold ligands might help to prevent the loss of unrelated TCRs during multiple responses, preserving the valuable diversity of the repertoire.
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Affiliation(s)
- Nevil J Singh
- Laboratory of Cellular and Molecular Immunology, NIAID, NIH, Bethesda, MD 20892, USA.
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32
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Quantification of lymph node transit times reveals differences in antigen surveillance strategies of naive CD4+ and CD8+ T cells. Proc Natl Acad Sci U S A 2012; 109:18036-41. [PMID: 23071319 DOI: 10.1073/pnas.1211717109] [Citation(s) in RCA: 120] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Naïve T cells continually recirculate between blood and secondary lymphoid organs, scanning dendritic cells (DC) for foreign antigen. Despite its importance for understanding how adaptive immune responses are efficiently initiated from rare precursors, a detailed quantitative analysis of this fundamental process has not been reported. Here we measure lymph node (LN) entry, transit, and exit rates for naïve CD4(+) and CD8(+) T cells, then use intravital imaging and mathematical modeling to relate cell-cell interaction dynamics to population behavior. Our studies reveal marked differences between CD4(+) vs. CD8(+) T cells. CD4(+) T cells recirculate more rapidly, homing to LNs more efficiently, traversing LNs twice as quickly, and spending ∼1/3 of their transit time interacting with MHCII on DC. In contrast, adoptively transferred CD8(+) T cells enter and leave the LN more slowly, with a transit time unaffected by the absence of MHCI molecules on host cells. Together, these data reveal an unexpectedly asymmetric role for MHC interactions in controlling CD4(+) vs. CD8(+) T lymphocyte recirculation, as well as distinct contributions of T cell receptor (TCR)-independent factors to the LN transit time, exposing the divergent surveillance strategies used by the two lymphocyte populations in scanning for foreign antigen.
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33
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Unexpected role for MHC II-peptide complexes in shaping CD8 T-cell expansion and differentiation in vivo. Proc Natl Acad Sci U S A 2012; 109:12698-703. [PMID: 22802622 DOI: 10.1073/pnas.1207219109] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Here we report a unique role for MHC II-peptide complexes in controlling immune responses of naïve CD8 T cells. Compared with CD8 T cells from WT mice, CD8 T cells isolated from MHC II(-/-) mice hyperproliferated under lymphopenic conditions, differentiated into effector cells producing proinflammatory cytokines, and mediated more severe tissue inflammation. The elevated responses of MHC II(-/-) CD8 T cells were due to the absence of MHC II, but not CD4, T cells. The hyperreactivity appeared to be a feature of mature T cells, given its absence in CD8 single positive thymocytes derived from MHC II(-/-) mice. Expression of the MHC II ligand LAG3 was markedly enhanced during in vivo activation of MHC II(-/-) CD8 T cells, and blockade of MHC II-LAG3 interactions further enhanced T-cell expansion. Importantly, CD8 T cells isolated from H-2M(-/-) mice expressing WT levels of MHC II also displayed hyperresponsiveness similar to that of MHC II(-/-) CD8 T cells, suggesting that peptides presented on MHC II are involved in the control of CD8 T-cell responses. Our results uncover a previously undefined MHC II-dependent regulation that tunes CD8 T-cell reactivity and may have implications for an improved understanding of CD8 T-cell homeostasis and functions.
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34
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Mittelstadt PR, Monteiro JP, Ashwell JD. Thymocyte responsiveness to endogenous glucocorticoids is required for immunological fitness. J Clin Invest 2012; 122:2384-94. [PMID: 22653054 DOI: 10.1172/jci63067] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2012] [Accepted: 04/18/2012] [Indexed: 12/21/2022] Open
Abstract
Generation of a self-tolerant but antigen-responsive T cell repertoire occurs in the thymus. Although glucocorticoids are usually considered immunosuppressive, there is also evidence that they play a positive role in thymocyte selection. To address the question of how endogenous glucocorticoids might influence the adaptive immune response, we generated GRlck-Cre mice, in which the glucocorticoid receptor gene (GR) is deleted in thymocytes prior to selection. These mice were immunocompromised, with reduced polyclonal T cell proliferative responses to alloantigen, defined peptide antigens, and viral infection. This was not due to an intrinsic proliferation defect, because GR-deficient T cells responded normally when the TCR was cross-linked with antibodies or when the T cell repertoire was "fixed" with αβ TCR transgenes. Varying the affinity of self ligands in αβ TCR transgenic mice showed that affinities that would normally lead to thymocyte-positive selection caused negative selection, and alterations in the TCR repertoire of polyclonal T cells were confirmed by analysis of TCR Vβ CDR3 regions. Thus, endogenous glucocorticoids are required for a robust adaptive immune response because of their promotion of the selection of T cells that have sufficient affinity for self, and the absence of thymocyte glucocorticoid signaling results in an immunocompromised state.
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Affiliation(s)
- Paul R Mittelstadt
- Laboratory of Immune Cell Biology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD, USA
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35
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Langerhans cells are precommitted to immune tolerance induction. Proc Natl Acad Sci U S A 2011; 108:18049-54. [PMID: 22006331 DOI: 10.1073/pnas.1110076108] [Citation(s) in RCA: 124] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Antigen-dependent interactions between T lymphocytes and dendritic cells (DCs) can produce two distinct outcomes: tolerance and immunity. It is generally considered that all DC subsets are capable of supporting both tolerogenic and immunogenic responses, depending on their exposure to activating signals. Here, we tested whether epidermal Langerhans cells (LCs) can support immunogenic responses in vivo in the absence of antigen presentation by other DC subsets. CD4 T cells responding to antigen presentation by activated LCs initially proliferated but then failed to differentiate into effector/memory cells or to survive long term. The tolerogenic function of LCs was maintained after exposure to potent adjuvants and occurred despite up-regulation of the costimulatory molecules CD80, CD86, and IL-12, but was consistent with their failure to translocate the NF-κB family member RelB from the cytoplasm to the nucleus. Commitment of LCs to tolerogenic function may explain why commensal microorganisms expressing Toll-like receptor (TLR) ligands but confined to the skin epithelium are tolerated, whereas invading pathogens that breach the epithelial basement membrane and activate dermal DCs stimulate a strong immune response.
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36
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Younes SA, Punkosdy G, Caucheteux S, Chen T, Grossman Z, Paul WE. Memory phenotype CD4 T cells undergoing rapid, nonburst-like, cytokine-driven proliferation can be distinguished from antigen-experienced memory cells. PLoS Biol 2011; 9:e1001171. [PMID: 22022231 PMCID: PMC3191130 DOI: 10.1371/journal.pbio.1001171] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2011] [Accepted: 08/30/2011] [Indexed: 11/24/2022] Open
Abstract
Contrary to the current paradigm that nearly all memory T cells proliferate in response to antigenic stimulation, this paper shows that an important population of CD4 T lymphocytes achieves memory/effector status independent of antigenic stimulation. Memory phenotype (CD44bright, CD25negative) CD4 spleen and lymph node T cells (MP cells) proliferate rapidly in normal or germ-free donors, with BrdU uptake rates of 6% to 10% per day and Ki-67 positivity of 18% to 35%. The rapid proliferation of MP cells stands in contrast to the much slower proliferation of lymphocytic choriomeningitis virus (LCMV)-specific memory cells that divide at rates ranging from <1% to 2% per day over the period from 15 to 60 days after LCMV infection. Anti-MHC class II antibodies fail to inhibit the in situ proliferation of MP cells, implying a non–T-cell receptor (TCR)-driven proliferation. Such proliferation is partially inhibited by anti–IL-7Rα antibody. The sequence diversity of TCRβ CDR3 gene segments is comparable among the proliferating and quiescent MP cells from conventional and germ-free mice, implying that the majority of proliferating MP cells have not recently derived from a small cohort of cells that expand through multiple continuous rounds of cell division. We propose that MP cells constitute a diverse cell population, containing a subpopulation of slowly dividing authentic antigen-primed memory cells and a majority population of rapidly proliferating cells that did not arise from naïve cells through conventional antigen-driven clonal expansion. The class of immune cells called CD4 T lymphocytes consists of two major cell types: naïve cells that have not yet participated in an immune response and memory cells, which are cells that have responded to antigen, expanded in number, and acquired new characteristics. These two cell types can be distinguished from one another because they display different cell surface marker proteins. In this paper, we argue that many—probably most—of the cells researchers generally characterize as memory cells on the basis of their surface markers are not authentic memory cells. True memory cells—the ones produced, for example, when we immunize a child against a disease—divide very slowly, whereas the bulk of the cells we generally characterize as memory cells divide very rapidly. Mice that have never been exposed to antigens have as many of these “memory-like” cells as normal mice have, implying that these cells arise by a process that does not require foreign antigen. Analysis of the sequence of the antigen recognition receptors on these “memory-like” cells indicates that their replication does not derive from a few cells or clones undergoing multiple rounds of proliferation, thus their division cannot be explained by conventional, antigen-driven clonal expansion. We conclude that this large population of “memory-like” cells has arisen by a mechanism independent of a response to foreign antigen, and that these cells may have a crucial biological function.
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Affiliation(s)
- Souheil-Antoine Younes
- Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - George Punkosdy
- Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Stephane Caucheteux
- Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Tao Chen
- Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Zvi Grossman
- Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - William E. Paul
- Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail:
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37
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Normal T cell homeostasis: the conversion of naive cells into memory-phenotype cells. Nat Immunol 2011; 12:478-84. [PMID: 21739670 DOI: 10.1038/ni.2018] [Citation(s) in RCA: 358] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Weak T cell antigen receptor (TCR) signals from contact with self ligands act in synergy with antiapoptotic signals induced by interleukin 7 (IL-7) to promote the survival of naive T cells in a resting state. The amount of background TCR signaling in naive T cells is set by post-thymic TCR tuning and operates at an intensity just below that required to induce entry into the cell cycle. Costimulation from higher concentrations of IL-7 and other common γ-chain cytokines can induce T cells to undergo homeostatic proliferation and conversion into cells with a memory phenotype; many of these memory phenotype cells may be the progeny of cells responding to self antigens. The molecular mechanisms that control the conversion of naive resting T cells into memory-phenotype cells TCR-dependent in normal animals are beginning to be understood.
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38
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Wu Q, Liu Y, Chen C, Ikenoue T, Qiao Y, Li CS, Li W, Guan KL, Liu Y, Zheng P. The tuberous sclerosis complex-mammalian target of rapamycin pathway maintains the quiescence and survival of naive T cells. THE JOURNAL OF IMMUNOLOGY 2011; 187:1106-12. [PMID: 21709159 DOI: 10.4049/jimmunol.1003968] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Naive T cells receive stimulation from the positive selecting ligand in the periphery for their survival. This stimulation does not normally lead to overt activation of T cells, as the T cells remain largely quiescent until they receive either antigenic or lymphopenic stimuli. The underlying mechanism responsible for survival and quiescence of the naive T cells remains largely unknown. In this study, we report that T cell-specific deletion of Tsc1, a negative regulator of mammalian target of rapamycin, resulted in both spontaneous losses of quiescence and cellularity, especially within the CD8 subset. The Tsc1-deficient T cells have increased cell proliferation and apoptosis. Tsc1 deletion affects the survival and quiescence of T cells in the absence of antigenic stimulation. Loss of quiescence but not cellularity was inhibited by rapamycin. Our data demonstrate that tuberous sclerosis complex-mammalian target of rapamycin maintains quiescence and survival of T cells.
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Affiliation(s)
- Qi Wu
- Department of Surgery, University of Michigan Medical School, Ann Arbor, MI 48109, USA
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39
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Godkin A, Gallimore A. Setting the threshold for extra-thymic differentiation of Foxp3+ Tregs: TGF-β-dependent and T-cell autonomous. Eur J Immunol 2011; 41:1218-20. [PMID: 21480216 DOI: 10.1002/eji.201141576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
There is a lack of clarity regarding the conditions supporting de novo induction of Tregs. While there is widespread agreement in the literature over the need for optimal stimulation conditions and exogenous TGF-β in vitro, a number of studies indicate that sub-immunogenic conditions induce Tregs in vivo. These seemingly disparate findings have hindered the ability to pin down the conditions promoting Treg induction, including the role of co-stimulation and even the necessity for TGF-β. Two studies in this issue of the European Journal of Immunology re-examine these previous findings in detail and shed some light on the controversy. These studies demonstrate that Treg induction depends on reaching a certain threshold of signal strength: the requirement for co-stimulation is therefore not absolute but dictated by the strength of other signals received by the T cell. Furthermore, these studies demonstrate that the only source of TGF-β required for the induction of Tregs under sub-optimal condition is the T cells themselves. Overall, the picture that emerges is one where sub-immunogenicity, rather than a requirement for exogenous TGF-β, defines the conditions that support TGF-β-dependent Foxp3 induction in a T-cell autonomous fashion. The next challenge lies in utilizing this knowledge for the purpose of inducing Tregs for therapeutic gain.
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Affiliation(s)
- Andrew Godkin
- Infection, Immunity and Biochemistry, School of Medicine, Cardiff University, UK
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40
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Mazzoccoli G, De Cata A, Greco A, Damato M, De Pinto DG, Montrano M, Marzulli N, Pia Dagostino M, Carughi S. Opposing circadian rhythms of CD3+, CD4+ and CD3+, CD8+ lymphocyte subpopulations in healthy humans. BIOL RHYTHM RES 2011. [DOI: 10.1080/09291011003726631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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41
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Jenkins MK, Chu HH, McLachlan JB, Moon JJ. On the composition of the preimmune repertoire of T cells specific for Peptide-major histocompatibility complex ligands. Annu Rev Immunol 2010; 28:275-94. [PMID: 20307209 DOI: 10.1146/annurev-immunol-030409-101253] [Citation(s) in RCA: 172] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Millions of T cells are produced in the thymus, each expressing a unique alpha/beta T cell receptor (TCR) capable of binding to a foreign peptide in the binding groove of a host major histocompatibility complex (MHC) molecule. T cell-mediated immunity to infection is due to the proliferation and differentiation of rare clones in the preimmune repertoire that by chance express TCRs specific for peptide-MHC (pMHC) ligands derived from the microorganism. Here we review recent findings that have altered our understanding of how the preimmune repertoire is established. Recent structural studies indicate that a germline-encoded tendency of TCRs to bind MHC molecules contributes to the MHC bias of T cell repertoires. It has also become clear that the preimmune repertoire contains functionally heterogeneous subsets including recent thymic emigrants, mature naive phenotype cells, memory phenotype cells, and natural regulatory T cells. In addition, sensitive new detection methods have revealed that the repertoire of naive phenotype T cells consists of distinct pMHC-specific populations that consistently vary in size in different individuals. The implications of these new findings for the clonal selection theory, self-tolerance, and immunodominance are discussed.
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Affiliation(s)
- Marc K Jenkins
- Department of Microbiology, Center for Immunology, University of Minnesota Medical School, Minneapolis, 55455, USA.
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Hochweller K, Wabnitz GH, Samstag Y, Suffner J, Hämmerling GJ, Garbi N. Dendritic cells control T cell tonic signaling required for responsiveness to foreign antigen. Proc Natl Acad Sci U S A 2010; 107:5931-6. [PMID: 20231464 PMCID: PMC2851879 DOI: 10.1073/pnas.0911877107] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Dendritic cells (DCs) are key components of the adaptive immune system contributing to initiation and regulation of T cell responses. T cells continuously scan DCs in lymphoid organs for the presence of foreign antigen. However, little is known about the functional consequences of these frequent T cell-DC interactions without cognate antigen. Here we demonstrate that these contacts in the absence of foreign antigen serve an important function, namely, induction of a basal activation level in T cells required for responsiveness to subsequent encounters with foreign antigens. This basal activation is provided by self-recognition of MHC molecules on DCs. Following DC depletion in mice, T cells became impaired in TCR signaling and immune synapse formation, and consequently were hyporesponsive to antigen. This process was reversible, as T cells quickly recovered when the number of DCs returned to a normal level. The extent of T cell reactivity correlated with the degree of DC depletion in lymphoid organs, suggesting that a full DC compartment guarantees optimal T cell responsiveness. These findings indicate that DCs are specialized cells that not only present foreign antigen, but also promote a "tonic" state in T cells for antigen responsiveness.
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Affiliation(s)
- Kristin Hochweller
- Division of Molecular Immunology, German Cancer Research Center, 69120 Heidelberg, Germany; and
| | - Guido H. Wabnitz
- Institute for Immunology, University of Heidelberg, 69129 Heidelberg, Germany
| | - Yvonne Samstag
- Institute for Immunology, University of Heidelberg, 69129 Heidelberg, Germany
| | - Janine Suffner
- Division of Molecular Immunology, German Cancer Research Center, 69120 Heidelberg, Germany; and
| | - Günter J. Hämmerling
- Division of Molecular Immunology, German Cancer Research Center, 69120 Heidelberg, Germany; and
| | - Natalio Garbi
- Division of Molecular Immunology, German Cancer Research Center, 69120 Heidelberg, Germany; and
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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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Houston EG, Fink PJ. MHC drives TCR repertoire shaping, but not maturation, in recent thymic emigrants. THE JOURNAL OF IMMUNOLOGY 2009; 183:7244-9. [PMID: 19915060 DOI: 10.4049/jimmunol.0902313] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
After developing in the thymus, recent thymic emigrants (RTEs) enter the lymphoid periphery and undergo a maturation process as they transition into the mature naive (MN) T cell compartment. This maturation presumably shapes RTEs into a pool of T cells best fit to function robustly in the periphery without causing autoimmunity; however, the mechanism and consequences of this maturation process remain unknown. Using a transgenic mouse system that specifically labels RTEs, we tested the influence of MHC molecules, key drivers of intrathymic T cell selection and naive peripheral T cell homeostasis, in shaping the RTE pool in the lymphoid periphery. We found that the TCRs expressed by RTEs are skewed to longer CDR3 regions compared with those of MN T cells, suggesting that MHC does streamline the TCR repertoire of T cells as they transition from the RTE to the MN T cell stage. This conclusion is borne out in studies in which the representation of individual TCRs was followed as a function of time since thymic egress. Surprisingly, we found that MHC is dispensable for the phenotypic and functional maturation of RTEs.
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Affiliation(s)
- Evan G Houston
- Department of Immunology, University of Washington, Seattle, Washington 98195, USA
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Takada K, Jameson SC. Self-class I MHC molecules support survival of naive CD8 T cells, but depress their functional sensitivity through regulation of CD8 expression levels. ACTA ACUST UNITED AC 2009; 206:2253-69. [PMID: 19752186 PMCID: PMC2757867 DOI: 10.1084/jem.20082553] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Previous studies have suggested that naive CD8 T cells require self-peptide–major histocompatability complex (MHC) complexes for maintenance. However, interpretation of such studies is complicated because of the involvement of lymphopenic animals, as lymphopenia drastically alters naive T cell homeostasis and function. In this study, we explored naive CD8 T cell survival and function in nonlymphopenic conditions by using bone marrow chimeric donors and hosts in which class I MHC expression is absent or limited to radiosensitive versus radioresistant cells. We found that long-term survival of naive CD8 T cells (but not CD4 T cells) was impaired in the absence of class I MHC. However, distinct from this effect, class I MHC deprivation also enhanced naive CD8 T cell responsiveness to low-affinity (but not high-affinity) peptide–MHC ligands. We found that this improved sensitivity was a consequence of up-regulated CD8 levels, which was mediated through a transcriptional mechanism. Hence, our data suggest that, in a nonlymphopenic setting, self-class I MHC molecules support CD8 T cell survival, but that these interactions also attenuate naive T cell sensitivity by dynamic tuning of CD8 levels.
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Affiliation(s)
- Kensuke Takada
- Center for Immunology, Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, MN 55455, USA
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Impact of the TCR signal on regulatory T cell homeostasis, function, and trafficking. PLoS One 2009; 4:e6580. [PMID: 19668367 PMCID: PMC2719063 DOI: 10.1371/journal.pone.0006580] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2009] [Accepted: 07/13/2009] [Indexed: 12/13/2022] Open
Abstract
Signaling through the T cell antigen receptor (TCR) is important for the homeostasis of naïve and memory CD4+ T cells. The significance of TCR signaling in regulatory T (Treg) cells has not been systematically addressed. Using an Ox40-cre allele that is prominently expressed in Treg cells, and a conditional null allele of the gene encoding p56Lck, we have examined the importance of TCR signaling in Treg cells. Inactivation of p56Lck resulted in abnormal Treg homeostasis characterized by impaired turnover, preferential redistribution to the lymph nodes, loss of suppressive function, and striking changes in gene expression. Abnormal Treg cell homeostasis and function did not reflect the involvement of p56Lck in CD4 function because these effects were not observed when CD4 expression was inactivated by Ox40-cre.The results make clear multiple aspects of Treg cell homeostasis and phenotype that are dependent on a sustained capacity to signal through the TCR.
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Grigorian A, Torossian S, Demetriou M. T-cell growth, cell surface organization, and the galectin-glycoprotein lattice. Immunol Rev 2009; 230:232-46. [PMID: 19594640 PMCID: PMC3059806 DOI: 10.1111/j.1600-065x.2009.00796.x] [Citation(s) in RCA: 107] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Basal, activation, and arrest signaling in T cells determines survival, coordinates responses to pathogens, and, when dysregulated, leads to loss of self-tolerance and autoimmunity. At the T-cell surface, transmembrane glycoproteins interact with galectins via their N-glycans, forming a molecular lattice that regulates membrane localization, clustering, and endocytosis of surface receptors. Galectin-T-cell receptor (TCR) binding prevents ligand-independent TCR signaling via Lck by blocking spontaneous clustering and CD4-Lck recruitment to TCR, and in turn F-actin transfer of TCR/CD4-Lck complexes to membrane microdomains. Peptide-major histocompatibility complexes overcome galectin-TCR binding to promote TCR clustering and signaling by Lck at the immune synapse. Galectin also localizes the tyrosine phosphatase CD45 to microdomains and the immune synapse, suppressing basal and activation signaling by Lck. Following activation, membrane turnover increases and galectin binding to cytotoxic T-lymphocyte antigen-4 (CTLA-4) enhances surface expression by inhibiting endocytosis, thereby promoting growth arrest. Galectins bind surface glycoproteins in proportion to the branching and number of N-glycans per protein, the latter an encoded feature of protein sequence. N-glycan branching is conditional to the activity of Golgi N-acetylglucosaminyl transferases I, II, IV and V (Mgat1, 2, 4, and 5) and metabolic supply of their donor substrate UDP-GlcNAc. Genetic and metabolic control of N-glycan branching co-regulate homeostatic set-points for basal, activation, and arrest signaling in T cells and, when disturbed, result in T-cell hyperactivity and autoimmunity.
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Affiliation(s)
- Ani Grigorian
- Department of Neurology, University of California, Irvine, CA, USA
| | - Sevan Torossian
- Department of Neurology, University of California, Irvine, CA, USA
| | - Michael Demetriou
- Department of Neurology, University of California, Irvine, CA, USA
- Department of Microbiology and Molecular Genetics, University of California, Irvine, CA, USA
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Modelling naive T-cell homeostasis: consequences of heritable cellular lifespan during ageing. Immunol Cell Biol 2009; 87:445-56. [PMID: 19290017 DOI: 10.1038/icb.2009.11] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Within an individual, the population of mature naive T cells is maintained throughout life by both input from the thymus and homeostatic proliferation in the periphery. Here, we develop a mathematical model of this process of naive T-cell homeostasis, and use it to explore questions of lifespan, inheritance and receptor repertoire during ageing. By assuming lifespan is largely determined by a heritable trait reset on mitosis, we show that homeostatic proliferation leads naturally to a longer lived population with age. A plausible candidate for the heritable trait influencing lifespan is T-cell receptor affinity for major histocompatibility molecules loaded with self-peptides. Concurrently with increasing lifespan, receptor diversity decreases with age, thus quantitatively linking these two phenomena. These results depend on the thymus involuting with age so that homeostatic proliferation becomes the dominant mode of replacement of the naive T-cell repertoire.
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Abstract
The peripheral mature T cell pool is regulated by complex homeostatic mechanisms. Naive T cells are maintained by interleukin-7 (IL-7) and T cell receptor (TCR) signaling from contact with major histocompatibility complex (MHC), which sustain expression of antiapoptotic molecules and allow the cells to survive in interphase. Competition for these ligands declines when T cell numbers are reduced and causes residual naive T cells to proliferate and differentiate into memory-like cells. This memory cell population is thus heterogeneous and comprised of cells derived from responses to both foreign and self-antigens. Typical memory cells are kept alive and induced to divide intermittently by a mixture of IL-7 and IL-15. This review highlights recent advances in how naive and memory T cell homeostasis is regulated.
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Affiliation(s)
- Charles D Surh
- The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, CA 92037, USA.
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Proapoptotic Bcl-2 family member Bim promotes persistent infection and limits protective immunity. Infect Immun 2007; 76:1179-85. [PMID: 18086806 DOI: 10.1128/iai.01093-06] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Following the peak of the T-cell response, most of the activated effector T cells die by apoptosis driven by the proapoptotic Bcl-2 family member Bim (Bcl-2-interacting mediator of death). Whether the absence of Bim-mediated T-cell apoptosis can affect protective immunity remains unclear. Here, we used a mouse model of Leishmania major infection, in which parasite persistence and protective immunity are controlled by an equilibrium reached between parasite-specific gamma interferon (IFN-gamma)-producing effector T cells and interleukin-10 (IL-10)-producing CD4+ CD25+ T regulatory cells. To further understand the role of Bim-mediated apoptosis in persistent infection and protective immunity, we infected Bim-/- mice with L. major. We found that the initial parasite growth and lesion development were similar in Bim-/- and wild-type mice after primary L. major infection. However, at later times after infection, Bim-/- mice had significantly increased L. major-specific CD4+ T-cell responses and were resistant to persistent infection. Interestingly, despite their resistance to primary L. major infection, Bim-/- mice displayed significantly enhanced protection against challenge with L. major. Increased resistance to challenge in Bim-/- mice was associated with a significant increase in the number of L. major-specific IFN-gamma-producing CD4+ T cells and a lack of IL-10 production at the challenge site. Taken together, these data suggest that Bim limits protective immunity and that the absence of Bim allows the host to bypass antigen persistence for maintenance of immunity against reinfection.
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