1
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Ishihara M, Miwa H, Fujiwara H, Akahori Y, Kato T, Tanaka Y, Tawara I, Shiku H. αβ-T cell receptor transduction gives superior mitochondrial function to γδ-T cells with promising persistence. iScience 2023; 26:107802. [PMID: 37720098 PMCID: PMC10502403 DOI: 10.1016/j.isci.2023.107802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 07/25/2023] [Accepted: 08/29/2023] [Indexed: 09/19/2023] Open
Abstract
Adoptive cell therapy using allogeneic γδ-T cells is a promising option for off-the-shelf T cell products with a low risk of graft-versus-host disease (GVHD). Long-term persistence may boost the clinical development of γδ-T cell products. In this study, we found that genetically modified Vγ9+Vδ2+ T cells expressing a tumor antigen-specific αβ-TCR and CD8 coreceptor (GMC) showed target-specific killing and excellent persistence. To determine the mechanisms underlying these promising effects, we investigated metabolic characteristics. Cytokine secretion by γδ-TCR-stimulated nongene-modified γδ-T cells (NGMCs) and αβ-TCR-stimulated GMCs was equally suppressed by a glycolysis inhibitor, although the cytokine secretion of αβ-TCR-stimulated GMCs was more strongly inhibited by ATP synthase inhibitors than that of γδ-TCR-stimulated NGMCs. Metabolomic and transcriptomic analyses, flow cytometry analysis using mitochondria-labeling dyes and extracellular flux analysis consistently suggest that αβ-TCR-transduced γδ-T cells acquire superior mitochondrial function. In conclusion, αβ-TCR-transduced γδ-T cells acquire superior mitochondrial function with promising persistence.
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Affiliation(s)
- Mikiya Ishihara
- Department of Medical Oncology, Mie University Hospital, 2-174 Edobashi, Tsu, Mie 514-8507, Japan
| | - Hiroshi Miwa
- Department of Personalized Cancer Immunotherapy, Mie University Graduate School of Medicine, 1577 Kurimamachiya-cho, Tsu, Mie 514-8507, Japan
| | - Hiroshi Fujiwara
- Department of Personalized Cancer Immunotherapy, Mie University Graduate School of Medicine, 1577 Kurimamachiya-cho, Tsu, Mie 514-8507, Japan
| | - Yasushi Akahori
- Department of Personalized Cancer Immunotherapy, Mie University Graduate School of Medicine, 1577 Kurimamachiya-cho, Tsu, Mie 514-8507, Japan
| | - Takuma Kato
- Department of Cellular and Molecular Immunology, Mie University Graduate School of Medicine, Tsu, Mie 514-8507, Japan
| | - Yoshimasa Tanaka
- Center for Medical Innovation, Nagasaki University, 1-7-1 Sakamoto, Nagasaki 852-8588, Japan
| | - Isao Tawara
- Department of Hematology and Oncology, Mie University Graduate School of Medicine, 2-174 Edobashi, Tsu, Mie 514-8507, Japan
| | - Hiroshi Shiku
- Department of Personalized Cancer Immunotherapy, Mie University Graduate School of Medicine, 1577 Kurimamachiya-cho, Tsu, Mie 514-8507, Japan
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2
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Boughter CT, Meier-Schellersheim M. Conserved biophysical compatibility among the highly variable germline-encoded regions shapes TCR-MHC interactions. eLife 2023; 12:e90681. [PMID: 37861280 PMCID: PMC10631762 DOI: 10.7554/elife.90681] [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: 07/03/2023] [Accepted: 10/19/2023] [Indexed: 10/21/2023] Open
Abstract
T cells are critically important components of the adaptive immune system primarily responsible for identifying and responding to pathogenic challenges. This recognition of pathogens is driven by the interaction between membrane-bound T cell receptors (TCRs) and antigenic peptides presented on major histocompatibility complex (MHC) molecules. The formation of the TCR-peptide-MHC complex (TCR-pMHC) involves interactions among germline-encoded and hypervariable amino acids. Germline-encoded and hypervariable regions can form contacts critical for complex formation, but only interactions between germline-encoded contacts are likely to be shared across many of all the possible productive TCR-pMHC complexes. Despite this, experimental investigation of these interactions have focused on only a small fraction of the possible interaction space. To address this, we analyzed every possible germline-encoded TCR-MHC contact in humans, thereby generating the first comprehensive characterization of these largely antigen-independent interactions. Our computational analysis suggests that germline-encoded TCR-MHC interactions that are conserved at the sequence level are rare due to the high amino acid diversity of the TCR CDR1 and CDR2 loops, and that such conservation is unlikely to dominate the dynamic protein-protein binding interface. Instead, we propose that binding properties such as the docking orientation are defined by regions of biophysical compatibility between these loops and the MHC surface.
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Affiliation(s)
- Christopher T Boughter
- Computational Biology Section, Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of HealthBethesdaUnited States
| | - Martin Meier-Schellersheim
- Computational Biology Section, Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of HealthBethesdaUnited States
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3
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Lo WL, Kuhlmann M, Rizzuto G, Ekiz HA, Kolawole EM, Revelo MP, Andargachew R, Li Z, Tsai YL, Marson A, Evavold BD, Zehn D, Weiss A. A single-amino acid substitution in the adaptor LAT accelerates TCR proofreading kinetics and alters T-cell selection, maintenance and function. Nat Immunol 2023; 24:676-689. [PMID: 36914891 PMCID: PMC10063449 DOI: 10.1038/s41590-023-01444-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Accepted: 01/25/2023] [Indexed: 03/14/2023]
Abstract
Mature T cells must discriminate between brief interactions with self-peptides and prolonged binding to agonists. The kinetic proofreading model posits that certain T-cell antigen receptor signaling nodes serve as molecular timers to facilitate such discrimination. However, the physiological significance of this regulatory mechanism and the pathological consequences of disrupting it are unknown. Here we report that accelerating the normally slow phosphorylation of the linker for activation of T cells (LAT) residue Y136 by introducing an adjacent Gly135Asp alteration (LATG135D) disrupts ligand discrimination in vivo. The enhanced self-reactivity of LATG135D T cells triggers excessive thymic negative selection and promotes T-cell anergy. During Listeria infection, LATG135D T cells expand more than wild-type counterparts in response to very weak stimuli but display an imbalance between effector and memory responses. Moreover, despite their enhanced engagement of central and peripheral tolerance mechanisms, mice bearing LATG135D show features associated with autoimmunity and immunopathology. Our data reveal the importance of kinetic proofreading in balancing tolerance and immunity.
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Affiliation(s)
- Wan-Lin Lo
- Division of Microbiology and Immunology, Department of Pathology, University of Utah School of Medicine, Salt Lake City, UT, USA.
| | - Miriam Kuhlmann
- Division of Animal Physiology and Immunology, School of Life Sciences, Technical University of Munich, Freising, Germany
| | - Gabrielle Rizzuto
- Human Oncology and Pathogenesis Program, Department of Pathology and Laboratory Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - H Atakan Ekiz
- Department of Molecular Biology and Genetics, Izmir Institute of Technology, Gulbahce, Turkey
| | - Elizabeth M Kolawole
- Division of Microbiology and Immunology, Department of Pathology, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Monica P Revelo
- Department of Pathology, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Rakieb Andargachew
- Division of Microbiology and Immunology, Department of Pathology, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Zhongmei Li
- Department of Microbiology and Immunology, University of California San Francisco, San Francisco, CA, USA
| | - Yuan-Li Tsai
- Division of Rheumatology, Rosalind Russell and Ephraim P. Engleman Arthritis Research Center, Department of Medicine, University of California San Francisco, San Francisco, CA, USA
| | - Alexander Marson
- Department of Microbiology and Immunology, University of California San Francisco, San Francisco, CA, USA
- Gladstone-UCSF Institute of Genomic Immunology, San Francisco, CA, USA
- Chan Zuckerberg Biohub, San Francisco, CA, USA
- Department of Medicine, University of California San Francisco, San Francisco, CA, USA
- Diabetes Center, University of California San Francisco, San Francisco, CA, USA
- Innovative Genomics Institute, University of California Berkeley, Berkeley, CA, USA
- UCSF Helen Diller Family Comprehensive Cancer Center, University of California San Francisco, San Francisco, CA, USA
- Parker Institute for Cancer Immunotherapy, University of California San Francisco, San Francisco, CA, USA
- Institute for Human Genetics, University of California San Francisco, San Francisco, CA, USA
| | - Brian D Evavold
- Division of Microbiology and Immunology, Department of Pathology, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Dietmar Zehn
- Division of Animal Physiology and Immunology, School of Life Sciences, Technical University of Munich, Freising, Germany.
| | - Arthur Weiss
- Division of Rheumatology, Rosalind Russell and Ephraim P. Engleman Arthritis Research Center, Department of Medicine, University of California San Francisco, San Francisco, CA, USA.
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4
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Van Laethem F, Bhattacharya A, Craveiro M, Lu J, Sun PD, Singer A. MHC-independent αβT cells: Lessons learned about thymic selection and MHC-restriction. Front Immunol 2022; 13:953160. [PMID: 35911724 PMCID: PMC9331304 DOI: 10.3389/fimmu.2022.953160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Accepted: 06/24/2022] [Indexed: 12/02/2022] Open
Abstract
Understanding the generation of an MHC-restricted T cell repertoire is the cornerstone of modern T cell immunology. The unique ability of αβT cells to only recognize peptide antigens presented by MHC molecules but not conformational antigens is referred to as MHC restriction. How MHC restriction is imposed on a very large T cell receptor (TCR) repertoire is still heavily debated. We recently proposed the selection model, which posits that newly re-arranged TCRs can structurally recognize a wide variety of antigens, ranging from peptides presented by MHC molecules to native proteins like cell surface markers. However, on a molecular level, the sequestration of the essential tyrosine kinase Lck by the coreceptors CD4 and CD8 allows only MHC-restricted TCRs to signal. In the absence of Lck sequestration, MHC-independent TCRs can signal and instruct the generation of mature αβT cells that can recognize native protein ligands. The selection model thus explains how only MHC-restricted TCRs can signal and survive thymic selection. In this review, we will discuss the genetic evidence that led to our selection model. We will summarize the selection mechanism and structural properties of MHC-independent TCRs and further discuss the various non-MHC ligands we have identified.
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Affiliation(s)
- François Van Laethem
- Lymphocyte Development Section, Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD, United States
- Department of Biological Hematology, Centre Hospitalier Universitaire (CHU) Montpellier, Montpellier, France
- *Correspondence: François Van Laethem, ,
| | - Abhisek Bhattacharya
- Lymphocyte Development Section, Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD, United States
| | - Marco Craveiro
- Lymphocyte Development Section, Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD, United States
| | - Jinghua Lu
- Structural Immunology Section, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, United States
| | - Peter D. Sun
- Structural Immunology Section, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, United States
| | - Alfred Singer
- Lymphocyte Development Section, Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD, United States
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5
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Zhao X, Wu LZ, Ng EKY, Leow KWS, Wei Q, Gascoigne NRJ, Brzostek J. Non-Stimulatory pMHC Enhance CD8 T Cell Effector Functions by Recruiting Coreceptor-Bound Lck. Front Immunol 2021; 12:721722. [PMID: 34707605 PMCID: PMC8542885 DOI: 10.3389/fimmu.2021.721722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Accepted: 09/20/2021] [Indexed: 11/17/2022] Open
Abstract
Under physiological conditions, CD8+ T cells need to recognize low numbers of antigenic pMHC class I complexes in the presence of a surplus of non-stimulatory, self pMHC class I on the surface of the APC. Non-stimulatory pMHC have been shown to enhance CD8+ T cell responses to low amounts of antigenic pMHC, in a phenomenon called co-agonism, but the physiological significance and molecular mechanism of this phenomenon are still poorly understood. Our data show that co-agonist pMHC class I complexes recruit CD8-bound Lck to the immune synapse to modulate CD8+ T cell signaling pathways, resulting in enhanced CD8+ T cell effector functions and proliferation, both in vitro and in vivo. Moreover, co-agonism can boost T cell proliferation through an extrinsic mechanism, with co-agonism primed CD8+ T cells enhancing Akt pathway activation and proliferation in neighboring CD8+ T cells primed with low amounts of antigen.
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Affiliation(s)
- Xiang Zhao
- Immunology Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Liang-Zhe Wu
- Immunology Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Esther K Y Ng
- Immunology Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Kerisa W S Leow
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Qianru Wei
- Immunology Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Nicholas R J Gascoigne
- Immunology Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Joanna Brzostek
- Immunology Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
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6
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Różycki B, Weikl TR. Cooperative Stabilization of Close-Contact Zones Leads to Sensitivity and Selectivity in T-Cell Recognition. Cells 2021; 10:1023. [PMID: 33926103 PMCID: PMC8145674 DOI: 10.3390/cells10051023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 04/19/2021] [Accepted: 04/20/2021] [Indexed: 11/30/2022] Open
Abstract
T cells are sensitive to 1 to 10 foreign-peptide-MHC complexes among a vast majority of self-peptide-MHC complexes, and discriminate selectively between peptide-MHC complexes that differ not much in their binding affinity to T-cell receptors (TCRs). Quantitative models that aim to explain this sensitivity and selectivity largely focus on single TCR/peptide-MHC complexes, but T cell adhesion involves a multitude of different complexes. In this article, we demonstrate in a three-dimensional computational model of T-cell adhesion that the cooperative stabilization of close-contact zones is sensitive to one to three foreign-peptide-MHC complexes and occurs at a rather sharp threshold affinity of these complexes, which implies selectivity. In these close-contact zones with lateral extensions of hundred to several hundred nanometers, few TCR/foreign-peptide-MHC complexes and many TCR/self-peptide-MHC complexes are segregated from LFA-1/ICAM-1 complexes that form at larger membrane separations. Previous high-resolution microscopy experiments indicate that the sensitivity and selectivity in the formation of closed-contact zones reported here are relevant for T-cell recognition, because the stabilization of close-contact zones by foreign, agonist peptide-MHC complexes precedes T-cell signaling and activation in the experiments.
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Affiliation(s)
- Bartosz Różycki
- Institute of Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warsaw, Poland;
| | - Thomas R. Weikl
- Department of Theory and Bio-Systems, Max Planck Institut of Colloids and Interfaces, Am Mühlenberg 1, 14476 Potsdam, Germany
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7
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Lo WL, Weiss A. Adapting T Cell Receptor Ligand Discrimination Capability via LAT. Front Immunol 2021; 12:673196. [PMID: 33936119 PMCID: PMC8085316 DOI: 10.3389/fimmu.2021.673196] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Accepted: 03/29/2021] [Indexed: 12/19/2022] Open
Abstract
Self- and non-self ligand discrimination is a core principle underlying T cell-mediated immunity. Mature αβ T cells can respond to a foreign peptide ligand presented by major histocompatibility complex molecules (pMHCs) on antigen presenting cells, on a background of continuously sensed self-pMHCs. How αβ T cells can properly balance high sensitivity and high specificity to foreign pMHCs, while surrounded by a sea of self-peptide ligands is not well understood. Such discrimination cannot be explained solely by the affinity parameters of T cell antigen receptor (TCR) and pMHC interaction. In this review, we will discuss how T cell ligand discrimination may be molecularly defined by events downstream of the TCR-pMHC interaction. We will discuss new evidence in support of the kinetic proofreading model of TCR ligand discrimination, and in particular how the kinetics of specific phosphorylation sites within the adaptor protein linker for activation of T cells (LAT) determine the outcome of TCR signaling. In addition, we will discuss emerging data regarding how some kinases, including ZAP-70 and LCK, may possess scaffolding functions to more efficiently direct their kinase activities.
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Affiliation(s)
- Wan-Lin Lo
- Division of Rheumatology, Rosalind Russell and Ephraim P. Engleman Arthritis Research Center, Department of Medicine, University of California, San Francisco, San Francisco, CA, United States
| | - Arthur Weiss
- Division of Rheumatology, Rosalind Russell and Ephraim P. Engleman Arthritis Research Center, Department of Medicine, University of California, San Francisco, San Francisco, CA, United States
- Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, CA, United States
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8
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ApoB-Specific CD4 + T Cells in Mouse and Human Atherosclerosis. Cells 2021; 10:cells10020446. [PMID: 33669769 PMCID: PMC7922692 DOI: 10.3390/cells10020446] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 02/15/2021] [Accepted: 02/17/2021] [Indexed: 12/11/2022] Open
Abstract
Atherosclerosis is a chronic inflammatory condition of the arterial wall that leads to the formation of vessel-occluding plaques within the subintimal space of middle-sized and larger arteries. While traditionally understood as a myeloid-driven lipid-storage disease, growing evidence suggests that the accumulation of low-density lipoprotein cholesterol (LDL-C) ignites an autoimmune response with CD4+ T-helper (TH) cells that recognize self-peptides from Apolipoprotein B (ApoB), the core protein of LDL-C. These autoreactive CD4+ T cells home to the atherosclerotic plaque, clonally expand, instruct other cells in the plaque, and induce clinical plaque instability. Recent developments in detecting antigen-specific cells at the single cell level have demonstrated that ApoB-reactive CD4+ T cells exist in humans and mice. Their phenotypes and functions deviate from classical immunological concepts of distinct and terminally differentiated TH immunity. Instead, ApoB-specific CD4+ T cells have a highly plastic phenotype, can acquire several, partially opposing and mixed transcriptional programs simultaneously, and transit from one TH subset into another over time. In this review, we highlight adaptive immune mechanisms in atherosclerosis with a focus on CD4+ T cells, introduce novel technologies to detect ApoB-specific CD4+ T cells at the single cell level, and discuss the potential impact of ApoB-driven autoimmunity in atherosclerosis.
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9
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CD5 dynamically calibrates basal NF-κB signaling in T cells during thymic development and peripheral activation. Proc Natl Acad Sci U S A 2020; 117:14342-14353. [PMID: 32513716 PMCID: PMC7322041 DOI: 10.1073/pnas.1922525117] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Immature T cells undergo a process of positive selection in the thymus when their new T cell receptor (TCR) engages and signals in response to self-peptides. As the T cell matures, a slew of negative regulatory molecules, including the inhibitory surface glycoprotein CD5, are up-regulated in proportion to the strength of the self-peptide signal. Together these regulators dampen TCR-proximal signaling and help avoid any subsequent peripheral activation of T cells by self-peptides. Paradoxically, antigen-specific T cells initially expressing more CD5 (CD5hi) have been found to better persist as effector/memory cells after a peripheral challenge. The molecular mechanisms underlying such a duality in CD5 function is not clear. We found that CD5 alters the basal activity of the NF-κB signaling in resting peripheral T cells. When CD5 was conditionally ablated, T cells were unable to maintain higher expression of the cytoplasmic NF-κB inhibitor IκBα. Consistent with this, resting CD5hi T cells expressed more of the NF-κB p65 protein than CD5lo cells, without significant increases in transcript levels, in the absence of TCR signals. This posttranslationally stabilized cellular NF-κB depot potentially confers a survival advantage to CD5hi T cells over CD5lo ones. Taken together, these data suggest a two-step model whereby the strength of self-peptide-induced TCR signal lead to the up-regulation of CD5, which subsequently maintains a proportional reserve of NF-κB in peripheral T cells poised for responding to agonistic antigen-driven T cell activation.
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10
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Ma CY, Marioni JC, Griffiths GM, Richard AC. Stimulation strength controls the rate of initiation but not the molecular organisation of TCR-induced signalling. eLife 2020; 9:e53948. [PMID: 32412411 PMCID: PMC7308083 DOI: 10.7554/elife.53948] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Accepted: 05/14/2020] [Indexed: 12/13/2022] Open
Abstract
Millions of naïve T cells with different TCRs may interact with a peptide-MHC ligand, but very few will activate. Remarkably, this fine control is orchestrated using a limited set of intracellular machinery. It remains unclear whether changes in stimulation strength alter the programme of signalling events leading to T cell activation. Using mass cytometry to simultaneously measure multiple signalling pathways during activation of murine CD8+ T cells, we found a programme of distal signalling events that is shared, regardless of the strength of TCR stimulation. Moreover, the relationship between transcription of early response genes Nr4a1 and Irf8 and activation of the ribosomal protein S6 is also conserved across stimuli. Instead, we found that stimulation strength dictates the rate with which cells initiate signalling through this network. These data suggest that TCR-induced signalling results in a coordinated activation program, modulated in rate but not organization by stimulation strength.
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MESH Headings
- Animals
- CD8-Positive T-Lymphocytes/drug effects
- CD8-Positive T-Lymphocytes/immunology
- CD8-Positive T-Lymphocytes/metabolism
- Cells, Cultured
- Female
- Flow Cytometry
- Interferon Regulatory Factors/genetics
- Interferon Regulatory Factors/metabolism
- Kinetics
- Ligands
- Lymphocyte Activation/drug effects
- Male
- Mice, Inbred C57BL
- Mice, Transgenic
- Nuclear Receptor Subfamily 4, Group A, Member 1/genetics
- Nuclear Receptor Subfamily 4, Group A, Member 1/metabolism
- Ovalbumin/pharmacology
- Peptide Fragments/pharmacology
- Phosphorylation
- Receptors, Antigen, T-Cell/agonists
- Receptors, Antigen, T-Cell/metabolism
- Ribosomal Protein S6/metabolism
- Signal Transduction/drug effects
- Single-Cell Analysis
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Affiliation(s)
- Claire Y Ma
- Cambridge Institute for Medical Research, University of CambridgeCambridgeUnited Kingdom
| | - John C Marioni
- Cancer Research UK Cambridge Institute, University of CambridgeCambridgeUnited Kingdom
- EMBL-European Bioinformatics Institute, Wellcome Genome CampusCambridgeUnited Kingdom
- Wellcome Sanger Institute, Wellcome Genome CampusCambridgeUnited Kingdom
| | - Gillian M Griffiths
- Cambridge Institute for Medical Research, University of CambridgeCambridgeUnited Kingdom
| | - Arianne C Richard
- Cambridge Institute for Medical Research, University of CambridgeCambridgeUnited Kingdom
- Cancer Research UK Cambridge Institute, University of CambridgeCambridgeUnited Kingdom
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11
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Lo WL, Shah NH, Rubin SA, Zhang W, Horkova V, Fallahee IR, Stepanek O, Zon LI, Kuriyan J, Weiss A. Slow phosphorylation of a tyrosine residue in LAT optimizes T cell ligand discrimination. Nat Immunol 2019; 20:1481-1493. [PMID: 31611699 PMCID: PMC6858552 DOI: 10.1038/s41590-019-0502-2] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Accepted: 08/20/2019] [Indexed: 02/07/2023]
Abstract
Self-non-self discrimination is central to T cell-mediated immunity. The kinetic proofreading model can explain T cell antigen receptor (TCR) ligand discrimination; however, the rate-limiting steps have not been identified. Here, we show that tyrosine phosphorylation of the T cell adapter protein LAT at position Y132 is a critical kinetic bottleneck for ligand discrimination. LAT phosphorylation at Y132, mediated by the kinase ZAP-70, leads to the recruitment and activation of phospholipase C-γ1 (PLC-γ1), an important effector molecule for T cell activation. The slow phosphorylation of Y132, relative to other phosphosites on LAT, is governed by a preceding glycine residue (G131) but can be accelerated by substituting this glycine with aspartate or glutamate. Acceleration of Y132 phosphorylation increases the speed and magnitude of PLC-γ1 activation and enhances T cell sensitivity to weaker stimuli, including weak agonists and self-peptides. These observations suggest that the slow phosphorylation of Y132 acts as a proofreading step to facilitate T cell ligand discrimination.
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Affiliation(s)
- Wan-Lin Lo
- Division of Rheumatology, Rosalind Russell and Ephraim P. Engleman Arthritis Research Center, Department of Medicine, University of California, San Francisco, San Francisco, CA, USA
| | - Neel H Shah
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA.,Department of Chemistry, Columbia University, New York, NY, USA
| | - Sara A Rubin
- Harvard Stem Cell Institute, Harvard University, Cambridge, MA, USA.,Stem Cell Program and Division of Hematology/Oncology, Boston Children's Hospital and Dana-Farber Cancer Institute; Program in Immunology, Harvard Medical School, Boston, MA, USA
| | - Weiguo Zhang
- Department of Immunology, Duke University Medical Center, Durham, NC, USA
| | - Veronika Horkova
- Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
| | - Ian R Fallahee
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Ondrej Stepanek
- Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
| | - Leonard I Zon
- Harvard Stem Cell Institute, Harvard University, Cambridge, MA, USA.,Stem Cell Program and Division of Hematology/Oncology, Boston Children's Hospital and Dana-Farber Cancer Institute; Program in Immunology, Harvard Medical School, Boston, MA, USA.,Howard Hughes Medical Institute, Boston Children's Hospital and Harvard University, Boston, MA, USA
| | - John Kuriyan
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA.,Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, CA, USA
| | - Arthur Weiss
- Division of Rheumatology, Rosalind Russell and Ephraim P. Engleman Arthritis Research Center, Department of Medicine, University of California, San Francisco, San Francisco, CA, USA. .,Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, CA, USA.
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12
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Stress-testing the relationship between T cell receptor/peptide-MHC affinity and cross-reactivity using peptide velcro. Proc Natl Acad Sci U S A 2018; 115:E7369-E7378. [PMID: 30021852 DOI: 10.1073/pnas.1802746115] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
T cell receptors (TCRs) bind to peptide-major histocompatibility complex (pMHC) with low affinity (Kd ∼ μM), which is generally assumed to facilitate cross-reactive TCR "scanning" of ligands. To understand the relationship between TCR/pMHC affinity and cross-reactivity, we sought to engineer an additional weak interaction, termed "velcro," between the TCR and pMHC to probe the specificities of TCRs at relatively low and high affinities. This additional interaction was generated through an eight-amino acid peptide library covalently linked to the N terminus of the MHC-bound peptide. Velcro was selected through an affinity-based isolation and was subsequently shown to enhance the cognate TCR/pMHC affinity in a peptide-dependent manner by ∼10-fold. This was sufficient to convert a nonstimulatory ultra-low-affinity ligand into a stimulatory ligand. An X-ray crystallographic structure revealed how velcro interacts with the TCR. To probe TCR cross-reactivity, we screened TCRs against yeast-displayed pMHC libraries with and without velcro, and found that the peptide cross-reactivity profiles of low-affinity (Kd > 100 μM) and high-affinity (Kd ∼ μM) TCR/pMHC interactions are remarkably similar. The conservation of recognition of the TCR for pMHC across affinities reveals the nature of low-affinity ligands for which there are important biological functions and has implications for understanding the specificities of affinity-matured TCRs.
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Zhao X, Sankaran S, Yap J, Too CT, Ho ZZ, Dolton G, Legut M, Ren EC, Sewell AK, Bertoletti A, MacAry PA, Brzostek J, Gascoigne NRJ. Nonstimulatory peptide-MHC enhances human T-cell antigen-specific responses by amplifying proximal TCR signaling. Nat Commun 2018; 9:2716. [PMID: 30006605 PMCID: PMC6045629 DOI: 10.1038/s41467-018-05288-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Accepted: 05/12/2018] [Indexed: 01/02/2023] Open
Abstract
Foreign antigens are presented by antigen-presenting cells in the presence of abundant endogenous peptides that are nonstimulatory to the T cell. In mouse T cells, endogenous, nonstimulatory peptides have been shown to enhance responses to specific peptide antigens, a phenomenon termed coagonism. However, whether coagonism also occurs in human T cells is unclear, and the molecular mechanism of coagonism is still under debate since CD4 and CD8 coagonism requires different interactions. Here we show that the nonstimulatory, HIV-derived peptide GAG enhances a specific human cytotoxic T lymphocyte response to HBV-derived epitopes presented by HLA-A*02:01. Coagonism in human T cells requires the CD8 coreceptor, but not T-cell receptor (TCR) binding to the nonstimulatory peptide–MHC. Coagonists enhance the phosphorylation and recruitment of several molecules involved in the TCR-proximal signaling pathway, suggesting that coagonists promote T-cell responses to antigenic pMHC by amplifying TCR-proximal signaling. Coagonism, the ability of nonstimulatory antigens to promote T-cell activation, has been reported in mice. Here the authors show that coagonism also occurs in human CD8 T cells, in which a nonstimulatory HIV GAG peptide enhances a specific T-cell response to a hepatitis B virus epitope by amplifying T-cell receptor signals.
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Affiliation(s)
- Xiang Zhao
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore, 117545, Singapore
| | - Shvetha Sankaran
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore, 117545, Singapore.,Immunology Programme, Life Sciences Institute, National University of Singapore, 28 Medical Drive, Centre for Life Sciences, Level 3, Singapore, 117456, Singapore
| | - Jiawei Yap
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore, 117545, Singapore
| | - Chien Tei Too
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore, 117545, Singapore.,Immunology Programme, Life Sciences Institute, National University of Singapore, 28 Medical Drive, Centre for Life Sciences, Level 3, Singapore, 117456, Singapore
| | - Zi Zong Ho
- Emerging Infectious Diseases Program, Duke-NUS Graduate Medical School, 8 College Road, Singapore, 169857, Singapore
| | - Garry Dolton
- Division of Infection and Immunity, Cardiff University School of Medicine, Henry Wellcome Building, University Hospital Wales, Heath Park, Cardiff, CF14 4XN, United Kingdom
| | - Mateusz Legut
- Division of Infection and Immunity, Cardiff University School of Medicine, Henry Wellcome Building, University Hospital Wales, Heath Park, Cardiff, CF14 4XN, United Kingdom
| | - Ee Chee Ren
- Singapore Immunology Network, A*STAR, 8A Biomedical Grove, Immunos #03-06, Singapore, 138648, Singapore
| | - Andrew K Sewell
- Division of Infection and Immunity, Cardiff University School of Medicine, Henry Wellcome Building, University Hospital Wales, Heath Park, Cardiff, CF14 4XN, United Kingdom.,Systems Immunity Research Institute, Cardiff University, Tenovus Building, Cardiff, CF14 4XN, United Kingdom
| | - Antonio Bertoletti
- Emerging Infectious Diseases Program, Duke-NUS Graduate Medical School, 8 College Road, Singapore, 169857, Singapore
| | - Paul A MacAry
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore, 117545, Singapore.,Immunology Programme, Life Sciences Institute, National University of Singapore, 28 Medical Drive, Centre for Life Sciences, Level 3, Singapore, 117456, Singapore.,NUS Graduate School for Integrative Sciences and Engineering (NGS), National University of Singapore, Centre for Life Sciences (CeLS), #05-01, 28 Medical Drive, Singapore, 117456, Singapore
| | - Joanna Brzostek
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore, 117545, Singapore.
| | - Nicholas R J Gascoigne
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore, 117545, Singapore. .,Immunology Programme, Life Sciences Institute, National University of Singapore, 28 Medical Drive, Centre for Life Sciences, Level 3, Singapore, 117456, Singapore. .,NUS Graduate School for Integrative Sciences and Engineering (NGS), National University of Singapore, Centre for Life Sciences (CeLS), #05-01, 28 Medical Drive, Singapore, 117456, Singapore.
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14
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Abstract
Thymocyte selection involves the positive and negative selection of the repertoire of T cell receptors (TCRs) such that the organism does not suffer autoimmunity, yet has the benefit of the ability to recognize any invading pathogen. The signal transduced through the TCR is translated into a number of different signaling cascades that result in transcription factor activity in the nucleus and changes to the cytoskeleton and motility. Negative selection involves inducing apoptosis in thymocytes that express strongly self-reactive TCRs, whereas positive selection must induce survival and differentiation programs in cells that are more weakly self-reactive. The TCR recognition event is analog by nature, but the outcome of signaling is not. A large number of molecules regulate the strength of the TCR-derived signal at various points in the cascades. This review discusses the various factors that can regulate the strength of the TCR signal during thymocyte development.
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Affiliation(s)
- Nicholas R J Gascoigne
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, and Immunology Program, National University of Singapore, Singapore 11759;
| | - Vasily Rybakin
- Laboratory of Immunobiology, REGA Institute, Department of Microbiology and Immunology, KU Leuven, Leuven 3000, Belgium
| | - Oreste Acuto
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, United Kingdom
| | - Joanna Brzostek
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, and Immunology Program, National University of Singapore, Singapore 11759;
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15
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Courtney AH, Lo WL, Weiss A. TCR Signaling: Mechanisms of Initiation and Propagation. Trends Biochem Sci 2017; 43:108-123. [PMID: 29269020 DOI: 10.1016/j.tibs.2017.11.008] [Citation(s) in RCA: 307] [Impact Index Per Article: 43.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Revised: 11/21/2017] [Accepted: 11/21/2017] [Indexed: 10/18/2022]
Abstract
The mechanisms by which a T cell detects antigen using its T cell antigen receptor (TCR) are crucial to our understanding of immunity and the harnessing of T cells therapeutically. A hallmark of the T cell response is the ability of T cells to quantitatively respond to antigenic ligands derived from pathogens while remaining inert to similar ligands derived from host tissues. Recent studies have revealed exciting properties of the TCR and the behaviors of its signaling effectors that are used to detect and discriminate between antigens. Here we highlight these recent findings, focusing on the proximal TCR signaling molecules Zap70, Lck, and LAT, to provide mechanistic models and insights into the exquisite sensitivity and specificity of the TCR.
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Affiliation(s)
- Adam H Courtney
- Division of Rheumatology, Rosalind Russell and Ephraim P. Engleman Arthritis Research Center, Department of Medicine, University of California, San Francisco, San Francisco, CA 94143, USA; Howard Hughes Medical Institute (HHMI), San Francisco, CA 94143, USA
| | - Wan-Lin Lo
- Division of Rheumatology, Rosalind Russell and Ephraim P. Engleman Arthritis Research Center, Department of Medicine, University of California, San Francisco, San Francisco, CA 94143, USA; Howard Hughes Medical Institute (HHMI), San Francisco, CA 94143, USA
| | - Arthur Weiss
- Division of Rheumatology, Rosalind Russell and Ephraim P. Engleman Arthritis Research Center, Department of Medicine, University of California, San Francisco, San Francisco, CA 94143, USA; Howard Hughes Medical Institute (HHMI), San Francisco, CA 94143, USA.
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16
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Takada K, Kondo K, Takahama Y. Generation of Peptides That Promote Positive Selection in the Thymus. THE JOURNAL OF IMMUNOLOGY 2017; 198:2215-2222. [PMID: 28264997 DOI: 10.4049/jimmunol.1601862] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Accepted: 11/29/2016] [Indexed: 11/19/2022]
Abstract
To establish an immunocompetent TCR repertoire that is useful yet harmless to the body, a de novo thymocyte repertoire generated through the rearrangement of genes that encode TCR is shaped in the thymus through positive and negative selection. The affinity between TCRs and self-peptides associated with MHC molecules determines the fate of developing thymocytes. Low-affinity TCR engagement with self-peptide-MHC complexes mediates positive selection, a process that primarily occurs in the thymic cortex. Massive efforts exerted by many laboratories have led to the characterization of peptides that can induce positive selection. Moreover, it is now evident that protein degradation machineries unique to cortical thymic epithelial cells play a crucial role in the production of MHC-associated self-peptides for inducing positive selection. This review summarizes current knowledge on positive selection-inducing self-peptides and Ag processing machineries in cortical thymic epithelial cells. Recent studies on the role of positive selection in the functional tuning of T cells are also discussed.
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Affiliation(s)
- Kensuke Takada
- Division of Experimental Immunology, Institute of Advanced Medical Sciences, University of Tokushima, Tokushima 770-8503, Japan
| | - Kenta Kondo
- Division of Experimental Immunology, Institute of Advanced Medical Sciences, University of Tokushima, Tokushima 770-8503, Japan
| | - Yousuke Takahama
- Division of Experimental Immunology, Institute of Advanced Medical Sciences, University of Tokushima, Tokushima 770-8503, Japan
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17
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Dong M, Artusa P, Kelly SA, Fournier M, Baldwin TA, Mandl JN, Melichar HJ. Alterations in the Thymic Selection Threshold Skew the Self-Reactivity of the TCR Repertoire in Neonates. THE JOURNAL OF IMMUNOLOGY 2017; 199:965-973. [PMID: 28659353 DOI: 10.4049/jimmunol.1602137] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Accepted: 06/02/2017] [Indexed: 12/19/2022]
Abstract
Neonatal and adult T cells differ in their effector functions. Although it is known that cell-intrinsic differences in mature T cells contribute to this phenomenon, the factors involved remain unclear. Given emerging evidence that the binding strength of a TCR for self-peptide presented by MHC (self-pMHC) impacts T cell function, we sought to determine whether altered thymic selection influences the self-reactivity of the TCR repertoire during ontogeny. We found that conventional and regulatory T cell subsets in the thymus of neonates and young mice expressed higher levels of cell surface CD5, a surrogate marker for TCR avidity for self-pMHC, as compared with their adult counterparts, and this difference in self-reactivity was independent of the germline bias of the neonatal TCR repertoire. The increased binding strength of the TCR repertoire for self-pMHC in neonates was not solely due to reported defects in clonal deletion. Rather, our data suggest that thymic selection is altered in young mice such that thymocytes bearing TCRs with low affinity for self-peptide are not efficiently selected into the neonatal repertoire, and stronger TCR signals accompany both conventional and regulatory T cell selection. Importantly, the distinct levels of T cell self-reactivity reflect physiologically relevant differences based on the preferential expansion of T cells from young mice to fill a lymphopenic environment. Therefore, differences in thymic selection in young versus adult mice skew the TCR repertoire, and the relatively higher self-reactivity of the T cell pool may contribute to the distinct immune responses observed in neonates.
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Affiliation(s)
- Mengqi Dong
- Maisonneuve-Rosemont Hospital Research Center, Montreal, Quebec H1T 2M4, Canada.,Department of Microbiology, Infectious Diseases, and Immunology, University of Montreal, Montreal, Quebec H3T 1J4, Canada
| | - Patricio Artusa
- Department of Physiology and McGill Research Centre for Complex Traits, McGill University, Montreal, Quebec H3G 1Y6, Canada
| | - Stephanie A Kelly
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta T6G 2E1, Canada; and
| | - Marilaine Fournier
- Maisonneuve-Rosemont Hospital Research Center, Montreal, Quebec H1T 2M4, Canada
| | - Troy A Baldwin
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta T6G 2E1, Canada; and
| | - Judith N Mandl
- Department of Physiology and McGill Research Centre for Complex Traits, McGill University, Montreal, Quebec H3G 1Y6, Canada
| | - Heather J Melichar
- Maisonneuve-Rosemont Hospital Research Center, Montreal, Quebec H1T 2M4, Canada; .,Department of Medicine, University of Montreal, Montreal, Quebec H3T 1J4, Canada
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18
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Attaf M, Holland SJ, Bartok I, Dyson J. αβ T cell receptor germline CDR regions moderate contact with MHC ligands and regulate peptide cross-reactivity. Sci Rep 2016; 6:35006. [PMID: 27775030 PMCID: PMC5075794 DOI: 10.1038/srep35006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Accepted: 09/22/2016] [Indexed: 12/18/2022] Open
Abstract
αβ T cells respond to peptide epitopes presented by major histocompatibility complex (MHC) molecules. The role of T cell receptor (TCR) germline complementarity determining regions (CDR1 and 2) in MHC restriction is not well understood. Here, we examine T cell development, MHC restriction and antigen recognition where germline CDR loop structure has been modified by multiple glycine/alanine substitutions. Surprisingly, loss of germline structure increases TCR engagement with MHC ligands leading to excessive loss of immature thymocytes. MHC restriction is, however, strictly maintained. The peripheral T cell repertoire is affected similarly, exhibiting elevated cross-reactivity to foreign peptides. Our findings are consistent with germline TCR structure optimising T cell cross-reactivity and immunity by moderating engagement with MHC ligands. This strategy may operate alongside co-receptor imposed MHC restriction, freeing germline TCR structure to adopt this novel role in the TCR-MHC interface.
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Affiliation(s)
- Meriem Attaf
- Section of Molecular Immunology, Department of Medicine, Imperial College London, Du Cane Road, London, W12 0NN, UK
| | - Stephan J Holland
- Section of Molecular Immunology, Department of Medicine, Imperial College London, Du Cane Road, London, W12 0NN, UK
| | - Istvan Bartok
- Section of Molecular Immunology, Department of Medicine, Imperial College London, Du Cane Road, London, W12 0NN, UK
| | - Julian Dyson
- Section of Molecular Immunology, Department of Medicine, Imperial College London, Du Cane Road, London, W12 0NN, UK
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19
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Ley K. 2015 Russell Ross Memorial Lecture in Vascular Biology: Protective Autoimmunity in Atherosclerosis. Arterioscler Thromb Vasc Biol 2016; 36:429-38. [PMID: 26821946 PMCID: PMC4970520 DOI: 10.1161/atvbaha.115.306009] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Accepted: 01/18/2016] [Indexed: 01/18/2023]
Abstract
Atherosclerosis is an inflammatory disease of the arterial wall. It is accompanied by an autoimmune response against apolipoprotein B-100, the core protein of low-density lipoprotein, which manifests as CD4 T cell and antibody responses. To assess the role of the autoimmune response in atherosclerosis, the nature of the CD4 T cell response against apolipoprotein B-100 was studied with and without vaccination with major histocompatibility complex-II-restricted apolipoprotein B-100 peptides. The immunologic basis of autoimmunity in atherosclerosis is discussed in the framework of theories of adaptive immunity. Older vaccination approaches are also discussed. Vaccinating Apoe(-/-) mice with major histocompatibility complex-II-restricted apolipoprotein B-100 peptides reduces atheroma burden in the aorta by ≈40%. The protective mechanism likely includes secretion of interleukin-10. Protective autoimmunity limits atherosclerosis in mice and suggests potential for developing preventative and therapeutic vaccines for humans.
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Affiliation(s)
- Klaus Ley
- From the La Jolla Institute for Allergy & Immunology and Department of Bioengineering, UCSD, La Jolla, CA
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20
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Takada K, Van Laethem F, Xing Y, Akane K, Suzuki H, Murata S, Tanaka K, Jameson SC, Singer A, Takahama Y. TCR affinity for thymoproteasome-dependent positively selecting peptides conditions antigen responsiveness in CD8(+) T cells. Nat Immunol 2015; 16:1069-76. [PMID: 26301566 DOI: 10.1038/ni.3237] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Accepted: 07/01/2015] [Indexed: 12/12/2022]
Abstract
In the thymus, low-affinity T cell antigen receptor (TCR) engagement facilitates positive selection of a useful T cell repertoire. Here we report that TCR responsiveness of mature CD8(+) T cells is fine tuned by their affinity for positively selecting peptides in the thymus and that optimal TCR responsiveness requires positive selection on major histocompatibility complex class I-associated peptides produced by the thymoproteasome, which is specifically expressed in the thymic cortical epithelium. Thymoproteasome-independent positive selection of monoclonal CD8(+) T cells results in aberrant TCR responsiveness, homeostatic maintenance and immune responses to infection. These results demonstrate a novel aspect of positive selection, in which TCR affinity for positively selecting peptides produced by thymic epithelium determines the subsequent antigen responsiveness of mature CD8(+) T cells in the periphery.
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Affiliation(s)
- Kensuke Takada
- Division of Experimental Immunology, Institute for Genome Research, University of Tokushima, Tokushima, Japan
| | - Francois Van Laethem
- Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Yan Xing
- Center for Immunology, Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, Minnesota, USA
| | - Kazuyuki Akane
- Department of Immunology, Graduate School of Medicine, Nagoya University, Nagoya, Japan
| | - Haruhiko Suzuki
- Department of Immunology, Graduate School of Medicine, Nagoya University, Nagoya, Japan
| | - Shigeo Murata
- Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo, Japan
| | - Keiji Tanaka
- Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Stephen C Jameson
- Center for Immunology, Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, Minnesota, USA
| | - Alfred Singer
- Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Yousuke Takahama
- Division of Experimental Immunology, Institute for Genome Research, University of Tokushima, Tokushima, Japan
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21
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Takada K, Takahama Y. Positive-Selection-Inducing Self-Peptides Displayed by Cortical Thymic Epithelial Cells. Adv Immunol 2015; 125:87-110. [DOI: 10.1016/bs.ai.2014.09.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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22
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Malecek K, Grigoryan A, Zhong S, Gu WJ, Johnson LA, Rosenberg SA, Cardozo T, Krogsgaard M. Specific increase in potency via structure-based design of a TCR. THE JOURNAL OF IMMUNOLOGY 2014; 193:2587-99. [PMID: 25070852 DOI: 10.4049/jimmunol.1302344] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Adoptive immunotherapy with Ag-specific T lymphocytes is a powerful strategy for cancer treatment. However, most tumor Ags are nonreactive "self" proteins, which presents an immunotherapy design challenge. Recent studies have shown that tumor-specific TCRs can be transduced into normal PBLs, which persist after transfer in ∼30% of patients and effectively destroy tumor cells in vivo. Although encouraging, the limited clinical responses underscore the need for enrichment of T cells with desirable antitumor capabilities prior to patient transfer. In this study, we used structure-based design to predict point mutations of a TCR (DMF5) that enhance its binding affinity for an agonist tumor Ag-MHC (peptide-MHC [pMHC]), Mart-1 (27L)-HLA-A2, which elicits full T cell activation to trigger immune responses. We analyzed the effects of selected TCR point mutations on T cell activation potency and analyzed cross-reactivity with related Ags. Our results showed that the mutated TCRs had improved T cell activation potency while retaining a high degree of specificity. Such affinity-optimized TCRs have demonstrated to be very specific for Mart-1 (27L), the epitope for which they were structurally designed. Although of somewhat limited clinical relevance, these studies open the possibility for future structural-based studies that could potentially be used in adoptive immunotherapy to treat melanoma while avoiding adverse autoimmunity-derived effects.
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Affiliation(s)
- Karolina Malecek
- Perlmutter Cancer Center, New York University School of Medicine, New York, NY 10016; Program in Structural Biology, New York University School of Medicine, New York, NY 10016
| | - Arsen Grigoryan
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016
| | - Shi Zhong
- Perlmutter Cancer Center, New York University School of Medicine, New York, NY 10016
| | - Wei Jun Gu
- Department of Chemistry, New York University, New York, NY 10012
| | - Laura A Johnson
- Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892; and
| | - Steven A Rosenberg
- Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892; and
| | - Timothy Cardozo
- Perlmutter Cancer Center, New York University School of Medicine, New York, NY 10016; Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016
| | - Michelle Krogsgaard
- Perlmutter Cancer Center, New York University School of Medicine, New York, NY 10016; Program in Structural Biology, New York University School of Medicine, New York, NY 10016; Interdisciplinary Melanoma Cooperative Group, New York University School of Medicine, New York, NY 10016
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23
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Dushek O, van der Merwe PA. An induced rebinding model of antigen discrimination. Trends Immunol 2014; 35:153-8. [PMID: 24636916 PMCID: PMC3989030 DOI: 10.1016/j.it.2014.02.002] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Revised: 02/10/2014] [Accepted: 02/11/2014] [Indexed: 12/01/2022]
Abstract
We propose that pMHC binding to TCR can increase (induce) pMHC rebinding. Published studies are consistent with an induced rebinding model. Induced rebinding improves the ability of T cells to discriminate antigens. Induced rebinding relates 3D to 2D TCR–pMHC binding parameters.
T cells have to detect rare high-affinity ‘foreign’ peptide MHC (pMHC) ligands among abundant low-affinity ‘self’-peptide MHC ligands. It remains unclear how this remarkable discrimination is achieved. Kinetic proofreading mechanisms can provide the required specificity but only at the expense of much reduced sensitivity. A number of recent observations suggest that pMHC engagement of T cell receptors (TCRs) induces changes such as clustering and/or conformational alterations that enhance subsequent rebinding. We show that inclusion of induced rebinding to the same pMHC in kinetic proofreading models enhances the sensitivity of TCR recognition while retaining specificity. Moreover, induced rebinding is able to reproduce the striking, and hitherto unexplained, 2D membrane-binding properties recently reported for the TCR.
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Affiliation(s)
- Omer Dushek
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK; Wolfson Centre for Mathematical Biology, University of Oxford, Oxford, UK.
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24
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Li XL, Teng MK, Reinherz EL, Wang JH. Strict Major Histocompatibility Complex Molecule Class-Specific Binding by Co-Receptors Enforces MHC-Restricted αβ TCR Recognition during T Lineage Subset Commitment. Front Immunol 2013; 4:383. [PMID: 24319443 PMCID: PMC3837227 DOI: 10.3389/fimmu.2013.00383] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Accepted: 11/04/2013] [Indexed: 01/22/2023] Open
Abstract
Since the discovery of co-receptor dependent αβTCR recognition, considerable effort has been spent on elucidating the basis of CD4 and CD8 lineage commitment in the thymus. The latter is responsible for generating mature CD4 helper and CD8αβ cytotoxic T cell subsets. Although CD4+ and CD8+ T cell recognition of peptide antigens is known to be MHC class II- and MHC class I-restricted, respectively, the mechanism of single positive (SP) thymocyte lineage commitment from bipotential double-positive (DP) progenitors is not fully elucidated. Classical models to explain thymic CD4 vs. CD8 fate determination have included a stochastic selection model or instructional models. The latter are based either on strength of signal or duration of signal impacting fate. More recently, differential co-receptor gene imprinting has been shown to be involved in expression of transcription factors impacting cytotoxic T cell development. Here, we address commitment from a structural perspective, focusing on the nature of co-receptor binding to MHC molecules. By surveying 58 MHC class II and 224 MHC class I crystal structures in the Protein Data Bank, it becomes clear that CD4 cannot bind to MHC I molecules, nor can CD8αβ or CD8αα bind to MHC II molecules. Given that the co-receptor delivers Lck to phosphorylate exposed CD3 ITAMs within a peptide/MHC (pMHC)-ligated TCR complex to initiate cell signaling, this strict co-receptor recognition fosters MHC class-restricted SP thymocyte lineage commitment at the DP stage even though both co-receptors are expressed on a single cell. In short, the binding preference of an αβTCR for a peptide complexed with an MHC molecule dictates which co-receptor subsequently binds, thereby supporting development of that subset lineage. How function within the lineage is linked further to biopotential fate determination is discussed.
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Affiliation(s)
- Xiao-Long Li
- School of Life Sciences, University of Science and Technology of China , Hefei , China ; College of Life Sciences, Peking University , Beijing , China
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25
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Themis sets the signal threshold for positive and negative selection in T-cell development. Nature 2013; 504:441-5. [PMID: 24226767 PMCID: PMC3977001 DOI: 10.1038/nature12718] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Accepted: 09/26/2013] [Indexed: 12/31/2022]
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26
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Mukherjee S, Rigaud S, Seok SC, Fu G, Prochenka A, Dworkin M, Gascoigne NRJ, Vieland VJ, Sauer K, Das J. In silico modeling of Itk activation kinetics in thymocytes suggests competing positive and negative IP4 mediated feedbacks increase robustness. PLoS One 2013; 8:e73937. [PMID: 24066087 PMCID: PMC3774804 DOI: 10.1371/journal.pone.0073937] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Accepted: 07/25/2013] [Indexed: 12/29/2022] Open
Abstract
The inositol-phosphate messenger inositol(1,3,4,5)tetrakisphosphate (IP4) is essential for thymocyte positive selection by regulating plasma-membrane association of the protein tyrosine kinase Itk downstream of the T cell receptor (TCR). IP4 can act as a soluble analog of the phosphoinositide 3-kinase (PI3K) membrane lipid product phosphatidylinositol(3,4,5)trisphosphate (PIP3). PIP3 recruits signaling proteins such as Itk to cellular membranes by binding to PH and other domains. In thymocytes, low-dose IP4 binding to the Itk PH domain surprisingly promoted and high-dose IP4 inhibited PIP3 binding of Itk PH domains. However, the mechanisms that underlie the regulation of membrane recruitment of Itk by IP4 and PIP3 remain unclear. The distinct Itk PH domain ability to oligomerize is consistent with a cooperative-allosteric mode of IP4 action. However, other possibilities cannot be ruled out due to difficulties in quantitatively measuring the interactions between Itk, IP4 and PIP3, and in generating non-oligomerizing Itk PH domain mutants. This has hindered a full mechanistic understanding of how IP4 controls Itk function. By combining experimentally measured kinetics of PLCγ1 phosphorylation by Itk with in silico modeling of multiple Itk signaling circuits and a maximum entropy (MaxEnt) based computational approach, we show that those in silico models which are most robust against variations of protein and lipid expression levels and kinetic rates at the single cell level share a cooperative-allosteric mode of Itk regulation by IP4 involving oligomeric Itk PH domains at the plasma membrane. This identifies MaxEnt as an excellent tool for quantifying robustness for complex TCR signaling circuits and provides testable predictions to further elucidate a controversial mechanism of PIP3 signaling.
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Affiliation(s)
- Sayak Mukherjee
- Battelle Center for Mathematical Medicine, The Research Institute at the Nationwide Children’s Hospital, Columbus, Ohio, United States of America
| | - Stephanie Rigaud
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, California, United States of America
| | - Sang-Cheol Seok
- Battelle Center for Mathematical Medicine, The Research Institute at the Nationwide Children’s Hospital, Columbus, Ohio, United States of America
| | - Guo Fu
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, California, United States of America
| | - Agnieszka Prochenka
- Battelle Center for Mathematical Medicine, The Research Institute at the Nationwide Children’s Hospital, Columbus, Ohio, United States of America
- Institute of Computer Science, Polish Academy of Sciences, Warsaw, Poland
| | - Michael Dworkin
- Battelle Center for Mathematical Medicine, The Research Institute at the Nationwide Children’s Hospital, Columbus, Ohio, United States of America
- Department of Mathematics, The Ohio State University, Columbus, Ohio, United States of America
| | - Nicholas R. J. Gascoigne
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, California, United States of America
| | - Veronica J. Vieland
- Battelle Center for Mathematical Medicine, The Research Institute at the Nationwide Children’s Hospital, Columbus, Ohio, United States of America
- Department of Pediatrics, The Ohio State University, Columbus, Ohio, United States of America
- Department of Statistics, The Ohio State University, Columbus, Ohio, United States of America
| | - Karsten Sauer
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, California, United States of America
- * E-mail: (KS); (JD)
| | - Jayajit Das
- Battelle Center for Mathematical Medicine, The Research Institute at the Nationwide Children’s Hospital, Columbus, Ohio, United States of America
- Department of Pediatrics, The Ohio State University, Columbus, Ohio, United States of America
- Department of Physics, The Ohio State University, Columbus, Ohio, United States of America
- Biophysics Graduate Program, The Ohio State University, Columbus, Ohio, United States of America
- * E-mail: (KS); (JD)
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27
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Hoerter JAH, Brzostek J, Artyomov MN, Abel SM, Casas J, Rybakin V, Ampudia J, Lotz C, Connolly JM, Chakraborty AK, Gould KG, Gascoigne NRJ. Coreceptor affinity for MHC defines peptide specificity requirements for TCR interaction with coagonist peptide-MHC. ACTA ACUST UNITED AC 2013; 210:1807-21. [PMID: 23940257 PMCID: PMC3754861 DOI: 10.1084/jem.20122528] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The requirement for the TCR to interact with coagonists, endogenous MHC–peptide complexes which do not themselves activate the T cell, decreases as the strength of the CD8–class I interaction increases. Recent work has demonstrated that nonstimulatory endogenous peptides can enhance T cell recognition of antigen, but MHCI- and MHCII-restricted systems have generated very different results. MHCII-restricted TCRs need to interact with the nonstimulatory peptide–MHC (pMHC), showing peptide specificity for activation enhancers or coagonists. In contrast, the MHCI-restricted cells studied to date show no such peptide specificity for coagonists, suggesting that CD8 binding to noncognate MHCI is more important. Here we show how this dichotomy can be resolved by varying CD8 and TCR binding to agonist and coagonists coupled with computer simulations, and we identify two distinct mechanisms by which CD8 influences the peptide specificity of coagonism. Mechanism 1 identifies the requirement of CD8 binding to noncognate ligand and suggests a direct relationship between the magnitude of coagonism and CD8 affinity for coagonist pMHCI. Mechanism 2 describes how the affinity of CD8 for agonist pMHCI changes the requirement for specific coagonist peptides. MHCs that bind CD8 strongly were tolerant of all or most peptides as coagonists, but weaker CD8-binding MHCs required stronger TCR binding to coagonist, limiting the potential coagonist peptides. These findings in MHCI systems also explain peptide-specific coagonism in MHCII-restricted cells, as CD4–MHCII interaction is generally weaker than CD8–MHCI.
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Affiliation(s)
- John A H Hoerter
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, CA 92037, USA
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28
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Schmidt J, Dojcinovic D, Guillaume P, Luescher I. Analysis, Isolation, and Activation of Antigen-Specific CD4(+) and CD8(+) T Cells by Soluble MHC-Peptide Complexes. Front Immunol 2013; 4:218. [PMID: 23908656 PMCID: PMC3726995 DOI: 10.3389/fimmu.2013.00218] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Accepted: 07/15/2013] [Indexed: 11/24/2022] Open
Abstract
T cells constitute the core of adaptive cellular immunity and protect higher organisms against pathogen infections and cancer. Monitoring of disease progression as well as prophylactic or therapeutic vaccines and immunotherapies call for conclusive detection, analysis, and sorting of antigen-specific T cells. This is possible by means of soluble recombinant ligands for T cells, i.e., MHC class I-peptide (pMHC I) complexes for CD8(+) T cells and MHC class II-peptide (pMHC II) complexes for CD4(+) T cells and flow cytometry. Here we review major developments in the development of pMHC staining reagents and their diverse applications and discuss perspectives of their use for basic and clinical investigations.
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Affiliation(s)
- Julien Schmidt
- Ludwig Center, University of Lausanne, Epalinges, Switzerland
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29
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Malecek K, Zhong S, McGary K, Yu C, Huang K, Johnson LA, Rosenberg SA, Krogsgaard M. Engineering improved T cell receptors using an alanine-scan guided T cell display selection system. J Immunol Methods 2013; 392:1-11. [PMID: 23500145 DOI: 10.1016/j.jim.2013.02.018] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2013] [Revised: 02/28/2013] [Accepted: 02/28/2013] [Indexed: 11/18/2022]
Abstract
T cell receptors (TCRs) on T cells recognize peptide-major histocompatibility complex (pMHC) molecules on the surface of antigen presenting cells and this interaction determines the T cell immune response. Due to negative selection, naturally occurring TCRs bind self (tumor) peptides with low affinity and have a much higher affinity for foreign antigens. This complicates isolation of naturally occurring, high affinity TCRs that mediate more effective tumor rejection for therapeutic purposes. An attractive approach to resolve this issue is to engineer high affinity TCRs in vitro using phage, yeast or mammalian TCR display systems. A caveat of these systems is that they rely on a large library by random mutagenesis due to the lack of knowledge regarding the specific interactions between the TCR and pMHC. We have focused on the mammalian retroviral display system because it uniquely allows for direct comparison of TCR-pMHC-binding properties with T-cell activation outcomes. Through an alanine-scanning approach, we are able to quickly map the key amino acid residues directly involved in TCR-pMHC interactions thereby significantly reducing the library size. Using this method, we demonstrate that for a self-antigen-specific human TCR (R6C12) the key residues for pMHC binding are located in the CDR3β region. This information was used as a basis for designing an efficacious TCR CDR3α library that allowed for selection of TCRs with higher avidity than the wild-type as evaluated through binding and activation experiments. This is a direct approach to target specific TCR residues in TCR library design to efficiently engineer high avidity TCRs that may potentially be used to enhance adoptive immunotherapy treatments.
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Affiliation(s)
- Karolina Malecek
- NYU Cancer institute, New York University School of Medicine, NewYork, NY 10016, USA
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30
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Birnbaum ME, Dong S, Garcia KC. Diversity-oriented approaches for interrogating T-cell receptor repertoire, ligand recognition, and function. Immunol Rev 2013; 250:82-101. [PMID: 23046124 DOI: 10.1111/imr.12006] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Molecular diversity lies at the heart of adaptive immunity. T-cell receptors and peptide-major histocompatibility complex molecules utilize and rely upon an enormous degree of diversity at the levels of genetics, chemistry, and structure to engage one another and carry out their functions. This high level of diversity complicates the systematic study of important aspects of T-cell biology, but recent technical advances have allowed for the ability to study diversity in a comprehensive manner. In this review, we assess insights gained into T-cell receptor function and biology from our increasingly precise ability to assess the T-cell repertoire as a whole or to perturb individual receptors with engineered reagents. We conclude with a perspective on a new class of high-affinity, non-stimulatory peptide ligands we have recently discovered using diversity-oriented techniques that challenges notions for how we think about T-cell receptor signaling.
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Affiliation(s)
- Michael E Birnbaum
- Department of Molecular and Cellular Physiology, Program in Immunology, Stanford University School of Medicine, CA, USA
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31
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Abstract
Abstract
The primary consequence of positive selection is to render thymocytes responsive to cytokines and chemokines expressed in the thymic medulla. In the present study, our main objective was to discover which cytokines could support the differentiation of positively selected thymocytes. To this end, we have developed an in vitro model suitable for high-throughput analyses of positive selection and CD8 T-cell differentiation. The model involves coculture of TCRhiCD5intCD69− double-positive (DP) thymocytes with peptide-pulsed OP9 cells and γc-cytokines. We report that IL-4, IL-7, and IL-21 have nonredundant effects on positively selected DP thymocytes. IL-7 signaling phosphorylates STAT5 and ERK; induces Foxo1, Klf2, and S1pr1; and supports the differentiation of classic CD8 T cells. IL-4 activates STAT6 and ERK and supports the differentiation of CD8intPD-L1hiCD44hiEOMES+ innate CD8 T cells. IL-21 is produced by thymic epithelial cells and the IL-21 receptor-α is strongly induced on DP thymocytes undergoing positive selection. IL-21 signaling phosphorylates STAT3 and STAT5, but not ERK, and does not support CD8 T-cell differentiation. However, IL-21 has a unique ability to up-regulate BCL-6, expand DP thymocytes undergoing positive selection, and increase the production of mature T cells. Our data suggest that injection of recombinant IL-21 might enhance thymic output in subjects with age- or disease-related thymic atrophy.
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32
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Self-peptides in TCR repertoire selection and peripheral T cell function. Curr Top Microbiol Immunol 2013; 373:49-67. [PMID: 23612987 DOI: 10.1007/82_2013_319] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The vertebrate antigen receptors are anticipatory in their antigen recognition and display a vast diversity. Antigen receptors are assembled through V(D)J recombination, in which one of each Variable, (Diverse), and Joining gene segment are randomly utilized and recombined. Both gene rearrangement and mutational insertion are generated through randomness; therefore, the process of antigen receptors generation requires a rigorous testing system to select every receptor which is useful to recognize foreign antigens, but which would cause no harm to self cells. In the case of T cell receptors (TCR), such a quality control responsibility rests in thymic positive and negative selection. In this review, we focus on the critical involvement of self-peptides in the generation of a T cell repertoire, discuss the role of T cell thymic development in shaping the specificity of TCR repertoire, and directing function fitness of mature T cells in periphery. Here, we consider thymic positive selection to be not merely a one-time maturing experience for an individual T cell, but a life-long imprinting which influences the function of each individual T cell in periphery.
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33
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Abstract
Using an elaborately evolved language of cytokines and chemokines as well as cell-cell interactions, the different components of the immune system communicate with each other and orchestrate a response (or wind one down). Immunological synapses are a key feature of the system in the ways in which they can facilitate and direct these responses. Studies analyzing the structure of an immune synapse as it forms between two cells have provided insight into how the stability and kinetics of this interaction ultimately affect the sensitivity, potency, and magnitude of a given response. Furthermore, we have gained an appreciation of how the immunological synapse provides directionality and contextual cues for downstream signaling and cellular decision-making. In this review, we discuss how using a variety of techniques, developed over the last decade, have allowed us to visualize and quantify key aspects of the dynamic synaptic interface and have furthered our understanding of their function. We describe some of the many characteristics of the immunological synapse that make it a vital part of intercellular communication and some of the questions that remain to be answered.
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Affiliation(s)
- Jianming Xie
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, USA
| | - Cristina M. Tato
- Institute for Immunity, Transplantation and Infection, Stanford University School of Medicine, Stanford, CA, USA
| | - Mark M. Davis
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, USA
- Institute for Immunity, Transplantation and Infection, Stanford University School of Medicine, Stanford, CA, USA
- The Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA, USA
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34
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Abstract
The bias of αβ T cells for MHC ligands has been proposed to be intrinsic to the T-cell receptor (TCR). Equally, the CD4 and CD8 coreceptors contribute to ligand restriction by colocalizing Lck with the TCR when MHC ligands are engaged. To determine the importance of intrinsic ligand bias, the germ-line TCR complementarity determining regions were extensively diversified in vivo. We show that engagement with MHC ligands during thymocyte selection and peripheral T-cell activation imposes remarkably little constraint over TCR structure. Such versatility is more consistent with an opportunist, rather than a predetermined, mode of interface formation. This hypothesis was experimentally confirmed by expressing a hybrid TCR containing TCR-γ chain germ-line complementarity determining regions, which engaged efficiently with MHC ligands.
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35
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A voltage-gated sodium channel is essential for the positive selection of CD4(+) T cells. Nat Immunol 2012; 13:880-7. [PMID: 22842345 PMCID: PMC3426661 DOI: 10.1038/ni.2379] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2012] [Accepted: 06/26/2012] [Indexed: 12/15/2022]
Abstract
Sustained Ca2+ entry into CD4+CD8+ double-positive thymocytes is required for positive selection. We identified a voltage-gated Na+ channel (VGSC), essential for positive selection of CD4+ T cells. Pharmacological inhibition of VGSC activity inhibitedsustained Ca2+ influx induced by positive-selecting ligands and in vitro positive selection of CD4+ but not CD8+ T cells. In vivo shRNA knockdown of Scn5a specifically inhibited positive selection of CD4+ T cells. Ectopic expression of VGSC in peripheral AND CD4+ T cells bestowed the ability to respond to a positively selecting ligand, directly demonstrating VGSC expression was responsible for increased sensitivity. Thus active VGSCs in thymocytes provide a mechanism by which a weak positive selecting signal can induce sustained Ca2+ signals required for CD4+ T cell development.
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36
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Xie J, Huppa JB, Newell EW, Huang J, Ebert PJR, Li QJ, Davis MM. Photocrosslinkable pMHC monomers stain T cells specifically and cause ligand-bound TCRs to be 'preferentially' transported to the cSMAC. Nat Immunol 2012; 13:674-80. [PMID: 22660579 PMCID: PMC3645478 DOI: 10.1038/ni.2344] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Accepted: 05/15/2012] [Indexed: 12/15/2022]
Abstract
The binding of T cell antigen receptors (TCRs) to specific complexes of peptide and major histocompatibility complex (pMHC) is typically of very low affinity, which necessitates the use of multimeric pMHC complexes to label T lymphocytes stably. We report here the development of pMHC complexes able to be crosslinked by ultraviolet irradiation; even as monomers, these efficiently and specifically stained cognate T cells. We also used this reagent to probe T cell activation and found that a covalently bound pMHC was more stimulatory than an agonist pMHC on lipid bilayers. This finding suggested that serial engagement of TCRs is dispensable for activation when a substantial fraction of TCRs are stably engaged. Finally, pMHC-bound TCRs were 'preferentially' transported into the central supramolecular activation cluster after activation, which suggested that ligand engagement enabled linkage of the TCR and its associated CD3 signaling molecules to the cytoskeleton.
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Affiliation(s)
- Jianming Xie
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, USA
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37
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Adams JJ, Narayanan S, Liu B, Birnbaum ME, Kruse AC, Bowerman NA, Chen W, Levin AM, Connolly JM, Zhu C, Kranz DM, Garcia KC. T cell receptor signaling is limited by docking geometry to peptide-major histocompatibility complex. Immunity 2012; 35:681-93. [PMID: 22101157 DOI: 10.1016/j.immuni.2011.09.013] [Citation(s) in RCA: 196] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2011] [Revised: 08/16/2011] [Accepted: 09/02/2011] [Indexed: 02/04/2023]
Abstract
T cell receptor (TCR) engagement of peptide-major histocompatibility complex (pMHC) is essential to adaptive immunity, but it is unknown whether TCR signaling responses are influenced by the binding topology of the TCR-peptide-MHC complex. We developed yeast-displayed pMHC libraries that enabled us to identify new peptide sequences reactive with a single TCR. Structural analysis showed that four peptides bound to the TCR with distinct 3D and 2D affinities using entirely different binding chemistries. Three of the peptides that shared a common docking mode, where key TCR-MHC germline interactions are preserved, induced TCR signaling. The fourth peptide failed to induce signaling and was recognized in a substantially different TCR-MHC binding mode that apparently exceeded geometric tolerances compatible with signaling. We suggest that the stereotypical TCR-MHC docking paradigm evolved from productive signaling geometries and that TCR signaling can be modulated by peptides that are recognized in alternative TCR-pMHC binding orientations.
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MESH Headings
- Amino Acid Motifs/immunology
- Amino Acid Sequence
- Animals
- Epitopes, T-Lymphocyte/chemistry
- Epitopes, T-Lymphocyte/immunology
- Epitopes, T-Lymphocyte/metabolism
- Histocompatibility Antigens Class I/chemistry
- Humans
- Lymphocyte Activation/immunology
- Mice
- Models, Molecular
- Peptide Library
- Peptides/chemistry
- Peptides/immunology
- Peptides/metabolism
- Protein Binding/immunology
- Protein Conformation
- Receptors, Antigen, T-Cell/chemistry
- Receptors, Antigen, T-Cell/immunology
- Receptors, Antigen, T-Cell/metabolism
- Reproducibility of Results
- Sequence Alignment
- Signal Transduction
- T-Lymphocytes/immunology
- T-Lymphocytes/metabolism
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Affiliation(s)
- Jarrett J Adams
- Howard Hughes Medical Institute, and Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA
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38
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Liblau RS, Wekerle H, Tisch RM. Cumulative autoimmunity: T cell clones recognizing several self-epitopes exhibit enhanced pathogenicity. Front Immunol 2011; 2:47. [PMID: 22566837 PMCID: PMC3342376 DOI: 10.3389/fimmu.2011.00047] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2011] [Accepted: 09/10/2011] [Indexed: 11/24/2022] Open
Abstract
T cell receptor (TCR) recognition is intrinsically polyspecific. In the field of autoimmunity, recognition of both self- and microbial peptides by a single TCR has led to the concept of molecular mimicry. However, findings made by our group and others clearly demonstrate that a given TCR can also recognize multiple distinct self-peptides. Based on experimental data we argue that recognition of several self-peptides increases the pathogenicity of an autoreactive T cell; a property we refer to as “cumulative autoimmunity.” The mechanisms of such increased pathogenicity, and the implications of cumulative autoimmunity regarding the pathophysiology of T cell-mediated autoimmune diseases will be discussed.
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39
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Abstract
A key challenge in nano-science is to design ligand-coated nano-particles that can bind selectively to surfaces that display the cognate receptors above a threshold (surface) concentration. Nano-particles that bind monovalently to a target surface do not discriminate sharply between surfaces with high and low receptor coverage. In contrast, "multivalent" nano-particles that can bind to a larger number of ligands simultaneously, display regimes of "super selectivity" where the fraction of bound particles varies sharply with the receptor concentration. We present numerical simulations that show that multivalent nano-particles can be designed such that they approach the "on-off" binding behavior ideal for receptor-concentration selective targeting. We propose a simple analytical model that accounts for the super selective behavior of multivalent nano-particles. The model shows that the super selectivity is due to the fact that the number of distinct ligand-receptor binding arrangements increases in a highly nonlinear way with receptor coverage. Somewhat counterintuitively, our study shows that selectivity can be improved by making the individual ligand-receptor bonds weaker. We propose a simple rule of thumb to predict the conditions under which super selectivity can be achieved. We validate our model predictions against the Monte Carlo simulations.
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40
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Stone JD, Aggen DH, Chervin AS, Narayanan S, Schmitt TM, Greenberg PD, Kranz DM. Opposite effects of endogenous peptide-MHC class I on T cell activity in the presence and absence of CD8. THE JOURNAL OF IMMUNOLOGY 2011; 186:5193-200. [PMID: 21451107 DOI: 10.4049/jimmunol.1003755] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Nonstimulatory or endogenous peptide-MHC (pepMHC) presented on the surfaces of APCs, either alone or alongside agonist pepMHC, plays various roles in T cell selection and activation. To examine these properties in more detail, we explored several model systems of TCR and pepMHC ligands with sufficient affinity to be activated in the absence of CD8. The TCRs had a range of affinities for agonist and nonstimulatory ligands and were restricted by MHC class I alleles with different properties. We observed CD8-independent antagonism from TCR-pepMHC interactions with very low affinities (e.g., K(D) = 300 μM). In addition, endogenous peptide-L(d) complexes on APCs antagonized activation of coreceptor (CD8)-negative 2C T cells even by the strong agonist QL9-L(d). In contrast, TCRs m33 and 3D-PYY, restricted by K(b) and D(b), respectively, did not show signs of antagonism by endogenous pepMHC in the absence of CD8. This did not appear to be an inherent difference in the ability of the TCRs to be antagonized, as altered peptide ligands could antagonize each TCR. In the presence of CD8, endogenous pepMHC ligands acted in some cases as coagonists. These results show that endogenous pepMHC molecules exhibit complex behavior in T cells, leading to either reduced activity (e.g., in cases of low coreceptor levels) or enhanced activity (e.g., in presence of coreceptor). The behavior may be influenced by the ability of different TCRs to recognize endogenous pepMHC but also perhaps by the inherent properties of the presenting MHC allele.
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Affiliation(s)
- Jennifer D Stone
- Department of Biochemistry, University of Illinois Urbana-Champaign, Urbana, IL 61801, USA.
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41
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Zhou B, Chen Q, Mallis RJ, Zhang H, Liu JH, Reinherz EL, Wang JH. A conserved hydrophobic patch on Vβ domains revealed by TCRβ chain crystal structures: Implications for pre-TCR dimerization. Front Immunol 2011; 2:5. [PMID: 22566796 PMCID: PMC3341985 DOI: 10.3389/fimmu.2011.00005] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2011] [Accepted: 02/15/2011] [Indexed: 01/21/2023] Open
Abstract
The αβ T cell receptor (TCR) is a multimeric complex whose β chain plays a crucial role in thymocyte development as well as antigen recognition by mature T lymphocytes. We report here crystal structures of individual β subunits, termed N15β (Vβ5.2Dβ2Jβ2.6Cβ2) and N30β (Vβ13Dβ1Jβ1.1Cβ2), derived from two αβ TCRs specific for the immunodominant vesicular stomatitis virus octapeptide (VSV-8) bound to the murine H-2Kb MHC class I molecule. The crystal packing of the N15β structure reveals a homodimer formed through two Vβ domains. The Vβ/Vβ module is topologically very similar to the Vα/Vβ module in the N15αβ heterodimer. By contrast, in the N30β structure, the Vβ domain’s external hydrophobic CFG face is covered by the neighboring molecule’s Cβ domain. In conjunction with systematic investigation of previously published TCR single-subunit structures, we identified several conserved residues forming a concave hydrophobic patch at the center of the CFG outer face of the Vβ and other V-type Ig-like domains. This hydrophobic patch is shielded from solvent exposure in the crystal packing, implying that it is unlikely to be thermodynamically stable if exposed on the thymocyte surface. Accordingly, we propose a dimeric pre-TCR model distinct from those suggested previously by others and discuss its functional and structural implications.
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Affiliation(s)
- Bo Zhou
- Laboratory of Immunobiology, Dana-Farber Cancer Institute, Harvard Medical School Boston, MA, USA
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42
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Affiliation(s)
- Emil R Unanue
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA
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43
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Gascoigne NRJ, Palmer E. Signaling in thymic selection. Curr Opin Immunol 2011; 23:207-12. [PMID: 21242076 DOI: 10.1016/j.coi.2010.12.017] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2010] [Accepted: 12/26/2010] [Indexed: 01/22/2023]
Abstract
T cell receptor signaling allows the developing thymocyte to undergo positive or negative selection, which is required for the formation of a useful mature T cell repertoire. Recent developments include the finding that much of the Lck kinase (required to initiate T cell signaling) is already in an active configuration before signaling. The analog strength of antigen binding to the T cell receptor binding may be translated into a digital signal by the amount of time the TCR is paired with a co-receptor carrying Lck. Downstream, the cellular localization of MAP kinase signaling is determined by the strength of the signal and in turn predicts positive or negative selection. A novel protein, Themis, is important in crossing the positive selection developmental checkpoint, but its mode of action is still uncertain. Commitment to the CD4 or CD8 lineage is influenced by the amount of ZAP-70 signaling and also by closely regulated responsiveness to intrathymic cytokines such as IL7.
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Affiliation(s)
- Nicholas R J Gascoigne
- Department of Immunology and Microbial Science, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.
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Ebert PJR, Li QJ, Huppa JB, Davis MM. Functional development of the T cell receptor for antigen. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2010; 92:65-100. [PMID: 20800817 PMCID: PMC4887107 DOI: 10.1016/s1877-1173(10)92004-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
For over three decades now, the T cell receptor (TCR) for antigen has not ceased to challenge the imaginations of cellular and molecular immunologists alike. T cell antigen recognition transcends every aspect of adaptive immunity: it shapes the T cell repertoire in the thymus and directs T cell-mediated effector functions in the periphery, where it is also central to the induction of peripheral tolerance. Yet, despite its central position, there remain many questions unresolved: how can one TCR be specific for one particular peptide-major histocompatibility complex (pMHC) ligand while also binding other pMHC ligands with an immunologically relevant affinity? And how can a T cell's extreme specificity (alterations of single methyl groups in their ligand can abrogate a response) and sensitivity (single agonist ligands on a cell surface are sufficient to trigger a measurable response) emerge from TCR-ligand interactions that are so low in affinity? Solving these questions is intimately tied to a fundamental understanding of molecular recognition dynamics within the many different contexts of various T cell-antigen presenting cell (APC) contacts: from the thymic APCs that shape the TCR repertoire and guide functional differentiation of developing T cells to the peripheral APCs that support homeostasis and provoke antigen responses in naïve, effector, memory, and regulatory T cells. Here, we discuss our recent findings relating to T cell antigen recognition and how this leads to the thymic development of foreign-antigen-responsive alphabetaT cells.
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Affiliation(s)
- Peter J R Ebert
- The Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, USA
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