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Kandasamy K, Johana NB, Tan LG, Tan Y, Yeo JSL, Yusof NNB, Li Z, Koh J, Ginhoux F, Chan JKY, Choolani M, Mattar CNZ. Maternal dendritic cells influence fetal allograft response following murine in-utero hematopoietic stem cell transplantation. Stem Cell Res Ther 2023; 14:136. [PMID: 37226255 DOI: 10.1186/s13287-023-03366-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Accepted: 05/05/2023] [Indexed: 05/26/2023] Open
Abstract
BACKGROUND Intrauterine hematopoietic stem cell transplantation (IUT), potentially curative in congenital haematological disease, is often inhibited by deleterious immune responses to donor cells resulting in subtherapeutic donor cell chimerism (DCC). Microchimerism of maternal immune cells (MMc) trafficked into transplanted recipients across the placenta may directly influence donor-specific alloresponsiveness, limiting DCC. We hypothesized that dendritic cells (DC) among trafficked MMc influence the development of tolerogenic or immunogenic responses towards donor cells, and investigated if maternal DC-depletion reduced recipient alloresponsiveness and enhanced DCC. METHODS Using transgenic CD11c.DTR (C57BL/6) female mice enabled transient maternal DC-depletion with a single dose of diphtheria toxin (DT). CD11c.DTR females and BALB/c males were cross-mated, producing hybrid pups. IUT was performed at E14 following maternal DT administration 24 h prior. Bone marrow-derived mononuclear cells were transplanted, obtained from semi-allogenic BALB/c (paternal-derived; pIUT), C57BL/6 (maternal-derived; mIUT), or fully allogenic (aIUT) C3H donor mice. Recipient F1 pups were analyzed for DCC, while maternal and IUT-recipient immune cell profile and reactivity were examined via mixed lymphocyte reactivity functional assays. T- and B-cell receptor repertoire diversity in maternal and recipient cells were examined following donor cell exposure. RESULTS DCC was highest and MMc was lowest following pIUT. In contrast, aIUT recipients had the lowest DCC and the highest MMc. In groups that were not DC-depleted, maternal cells trafficked post-IUT displayed reduced TCR & BCR clonotype diversity, while clonotype diversity was restored when dams were DC-depleted. Additionally, recipients displayed increased expression of regulatory T-cells and immune-inhibitory proteins, with reduced proinflammatory cytokine and donor-specific antibody production. DC-depletion did not impact initial donor chimerism. Postnatal transplantation without immunosuppression of paternal donor cells did not increase DCC in pIUT recipients; however there were no donor-specific antibody production or immune cell changes. CONCLUSIONS Though maternal DC depletion did not improve DCC, we show for the first time that MMc influences donor-specific alloresponsiveness, possibly by expanding alloreactive clonotypes, and depleting maternal DC promotes and maintains acquired tolerance to donor cells independent of DCC, presenting a novel approach to enhancing donor cell tolerance following IUT. This may have value when planning repeat HSC transplantations to treat haemoglobinopathies.
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Affiliation(s)
- Karthikeyan Kandasamy
- Experimental Fetal Medicine Group, Department of Obstetrics and Gynaecology, Yong Loo Lin School of Medicine, National University of Singapore, 1E Kent Ridge Road, Singapore, 119228, Singapore
| | | | - Lay Geok Tan
- Experimental Fetal Medicine Group, Department of Obstetrics and Gynaecology, Yong Loo Lin School of Medicine, National University of Singapore, 1E Kent Ridge Road, Singapore, 119228, Singapore
- Department of Obstetrics and Gynaecology, National University Health System, National University Hospital, Singapore, Singapore
| | - Yvonne Tan
- Reproductive Medicine, KK Women's and Children's Hospital, Singapore, Singapore
| | - Julie Su Li Yeo
- Reproductive Medicine, KK Women's and Children's Hospital, Singapore, Singapore
| | - Nur Nazneen Binte Yusof
- Experimental Fetal Medicine Group, Department of Obstetrics and Gynaecology, Yong Loo Lin School of Medicine, National University of Singapore, 1E Kent Ridge Road, Singapore, 119228, Singapore
| | - Zhihui Li
- Genome Research Informatics and Data Science Platform, Genome Institute of Singapore, Agency for Science Technology and Research, Singapore, Singapore
| | - Jiayu Koh
- Genome Research Informatics and Data Science Platform, Genome Institute of Singapore, Agency for Science Technology and Research, Singapore, Singapore
| | - Florent Ginhoux
- Singapore Immunology Network (SIgN), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
- Translational Immunology Institute, Singhealth/Duke-NUS Academic Medical Centre, The Academia, Singapore, Singapore
- Shanghai Institute of Immunology, Shanghai JiaoTong University School of Medicine, Shanghai, China
| | - Jerry K Y Chan
- Experimental Fetal Medicine Group, Department of Obstetrics and Gynaecology, Yong Loo Lin School of Medicine, National University of Singapore, 1E Kent Ridge Road, Singapore, 119228, Singapore
- Reproductive Medicine, KK Women's and Children's Hospital, Singapore, Singapore
- Cancer and Stem Cell Biology Program, Duke-NUS Graduate Medical School, Singapore, Singapore
| | - Mahesh Choolani
- Experimental Fetal Medicine Group, Department of Obstetrics and Gynaecology, Yong Loo Lin School of Medicine, National University of Singapore, 1E Kent Ridge Road, Singapore, 119228, Singapore
- Department of Obstetrics and Gynaecology, National University Health System, National University Hospital, Singapore, Singapore
| | - Citra N Z Mattar
- Experimental Fetal Medicine Group, Department of Obstetrics and Gynaecology, Yong Loo Lin School of Medicine, National University of Singapore, 1E Kent Ridge Road, Singapore, 119228, Singapore.
- Department of Obstetrics and Gynaecology, National University Health System, National University Hospital, Singapore, Singapore.
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2
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Mizsei R, Li X, Chen WN, Szabo M, Wang JH, Wagner G, Reinherz EL, Mallis RJ. A general chemical crosslinking strategy for structural analyses of weakly interacting proteins applied to preTCR-pMHC complexes. J Biol Chem 2021; 296:100255. [PMID: 33837736 PMCID: PMC7948749 DOI: 10.1016/j.jbc.2021.100255] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 12/29/2020] [Accepted: 01/04/2021] [Indexed: 11/04/2022] Open
Abstract
T lymphocytes discriminate between healthy and infected or cancerous cells via T-cell receptor-mediated recognition of peptides bound and presented by cell-surface-expressed major histocompatibility complex molecules (MHCs). Pre-T-cell receptors (preTCRs) on thymocytes foster development of αβT lymphocytes through their β chain interaction with MHC displaying self-peptides on thymic epithelia. The specific binding of a preTCR with a peptide-MHC complex (pMHC) has been identified previously as forming a weak affinity complex with a distinct interface from that of mature αβTCR. However, a lack of appropriate tools has limited prior efforts to investigate this unique interface. Here we designed a small-scale linkage screening protocol using bismaleimide linkers for determining residue-specific distance constraints between transiently interacting protein pairs in solution. Employing linkage distance restraint-guided molecular modeling, we report the oriented solution docking geometry of a preTCRβ-pMHC interaction. The linkage model of preTCRβ-pMHC complex was independently verified with paramagnetic pseudocontact chemical shift (PCS) NMR of the unlinked protein mixtures. Using linkage screens, we show that the preTCR binds with differing affinities to peptides presented by MHC in solution. Moreover, the C-terminal peptide segment is a key determinant in preTCR-pMHC recognition. We also describe the process for future large-scale production and purification of the linked constructs for NMR, X-ray crystallography, and single-molecule electron microscopy studies.
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MESH Headings
- Antigens, Surface/chemistry
- Antigens, Surface/genetics
- Antigens, Surface/ultrastructure
- Humans
- Major Histocompatibility Complex/genetics
- Membrane Glycoproteins/chemistry
- Membrane Glycoproteins/ultrastructure
- Nuclear Magnetic Resonance, Biomolecular
- Peptides/chemistry
- Peptides/genetics
- Protein Binding/genetics
- Protein Interaction Domains and Motifs/genetics
- Receptors, Antigen, T-Cell/chemistry
- Receptors, Antigen, T-Cell/genetics
- Receptors, Antigen, T-Cell/ultrastructure
- Receptors, Antigen, T-Cell, alpha-beta/chemistry
- Receptors, Antigen, T-Cell, alpha-beta/ultrastructure
- T-Lymphocytes/chemistry
- T-Lymphocytes/immunology
- T-Lymphocytes/ultrastructure
- Thymocytes/chemistry
- Thymocytes/ultrastructure
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Affiliation(s)
- Réka Mizsei
- Laboratory of Immunobiology, Dana Farber Cancer Institute, Boston, Massachusetts, USA; Department of Biochemistry, Semmelweis University, Budapest, Hungary
| | - Xiaolong Li
- Laboratory of Immunobiology, Dana Farber Cancer Institute, Boston, Massachusetts, USA; Department of Medical Oncology, Dana Farber Cancer Institute, Boston, Massachusetts, USA; Department of Medicine, Harvard Medical School, Boston, Massachusetts, USA
| | - Wan-Na Chen
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, USA
| | - Monika Szabo
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
| | - Jia-Huai Wang
- Laboratory of Immunobiology, Dana Farber Cancer Institute, Boston, Massachusetts, USA; Department of Medical Oncology, Dana Farber Cancer Institute, Boston, Massachusetts, USA; Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, USA; Department of Cancer Biology, Dana Farber Cancer Institute, Boston, Massachusetts, USA; Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, USA
| | - Gerhard Wagner
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, USA
| | - Ellis L Reinherz
- Laboratory of Immunobiology, Dana Farber Cancer Institute, Boston, Massachusetts, USA; Department of Medical Oncology, Dana Farber Cancer Institute, Boston, Massachusetts, USA; Department of Medicine, Harvard Medical School, Boston, Massachusetts, USA.
| | - Robert J Mallis
- Laboratory of Immunobiology, Dana Farber Cancer Institute, Boston, Massachusetts, USA; Department of Medical Oncology, Dana Farber Cancer Institute, Boston, Massachusetts, USA; Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, USA; Department of Dermatology, Harvard Medical School, Boston, Massachusetts, USA.
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3
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Mallis RJ, Brazin KN, Duke-Cohan JS, Hwang W, Wang JH, Wagner G, Arthanari H, Lang MJ, Reinherz EL. NMR: an essential structural tool for integrative studies of T cell development, pMHC ligand recognition and TCR mechanobiology. JOURNAL OF BIOMOLECULAR NMR 2019; 73:319-332. [PMID: 30815789 PMCID: PMC6693947 DOI: 10.1007/s10858-019-00234-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Accepted: 02/06/2019] [Indexed: 05/05/2023]
Abstract
Early studies of T cell structural biology using X-ray crystallography, surface plasmon resonance (SPR) and isothermal titration calorimetry (ITC) focused on a picture of the αβT cell receptor (αβTCR) component domains and their cognate ligands (peptides bound to MHC molecules, i.e. pMHCs) as static interaction partners. Moving forward requires integrating this corpus of data with dynamic technologies such as NMR, molecular dynamics (MD) simulations and real-time single molecule (SM) studies exemplified by optical tweezers (OT). NMR bridges relevant timescales and provides the potential for an all-atom dynamic description of αβTCR components prior to and during interactions with binding partners. SM techniques have opened up vistas in understanding the non-equilibrium nature of T cell signaling through the introduction of force-mediated binding measurements into the paradigm for T cell function. In this regard, bioforces consequent to T-lineage cell motility are now perceived as placing piconewton (pN)-level loads on single receptor-pMHC bonds to impact structural change and αβT-lineage biology, including peptide discrimination, cellular activation, and developmental progression. We discuss herein essential NMR technologies in illuminating the role of ligand binding in the preT cell receptor (preTCR), the αβTCR developmental precursor, and convergence of NMR, SM and MD data in advancing our comprehension of T cell development. More broadly we review the central hypothesis that the αβTCR is a mechanosensor, fostered by breakthrough NMR-based structural insights. Collectively, elucidating dynamic aspects through the integrative use of NMR, SM, and MD shall advance fundamental appreciation of the mechanism of T cell signaling as well as inform translational efforts in αβTCR and chimeric T cell (CAR-T) immunotherapies and T cell vaccinology.
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Affiliation(s)
- Robert J Mallis
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, 02115, USA
- Department of Dermatology, Harvard Medical School, Boston, MA, 02115, USA
- Laboratory of Immunobiology, Dana-Farber Cancer Institute, Boston, MA, 02115, USA
| | - Kristine N Brazin
- Laboratory of Immunobiology, Dana-Farber Cancer Institute, Boston, MA, 02115, USA
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, 02115, USA
- Department of Medicine, Harvard Medical School, Boston, MA, 02115, USA
| | - Jonathan S Duke-Cohan
- Laboratory of Immunobiology, Dana-Farber Cancer Institute, Boston, MA, 02115, USA
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, 02115, USA
- Department of Medicine, Harvard Medical School, Boston, MA, 02115, USA
| | - Wonmuk Hwang
- Department of Biomedical Engineering, Texas A&M University, College Station, TX, 77843, USA
- Department of Materials Science & Engineering, Texas A&M University, College Station, TX, 77843, USA
- School of Computational Sciences, Korea Institute for Advanced Study, Seoul, 02455, Republic of Korea
| | - Jia-Huai Wang
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, 02115, USA
- Laboratory of Immunobiology, Dana-Farber Cancer Institute, Boston, MA, 02115, USA
- Department of Pediatrics, Harvard Medical School, Boston, MA, 02115, USA
| | - Gerhard Wagner
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, 02115, USA
| | - Haribabu Arthanari
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, 02115, USA.
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, 02115, USA.
| | - Matthew J Lang
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN, 37235, USA.
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN, 37235, USA.
| | - Ellis L Reinherz
- Laboratory of Immunobiology, Dana-Farber Cancer Institute, Boston, MA, 02115, USA.
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, 02115, USA.
- Department of Medicine, Harvard Medical School, Boston, MA, 02115, USA.
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4
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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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5
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Cohn M. Thoughts on Positive Selection in Thymus. Scand J Immunol 2016; 83:303-10. [PMID: 26834041 DOI: 10.1111/sji.12415] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Accepted: 01/25/2016] [Indexed: 12/25/2022]
Abstract
Any analysis of the mechanism of signalling during positive selection in the thymus is dependent on one's model of the TCR-ligand interaction. To date, thinking about mechanism has been dominated by what might be termed the Standard (or Centric) model, which is based on analogy between the BCR and the TCR. As the present analysis is an independent rationalized view of the TCR-ligand interactions, it permits a more balanced view of positive selection. The goal here was to explore this alternative to the Standard model.
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Affiliation(s)
- M Cohn
- Conceptual Immunology Group, The Salk Institute, La Jolla, CA, USA
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6
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Reinherz EL, Wang JH. Codification of bidentate pMHC interaction with TCR and its co-receptor. Trends Immunol 2015; 36:300-6. [PMID: 25818864 PMCID: PMC4420642 DOI: 10.1016/j.it.2015.03.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Revised: 03/03/2015] [Accepted: 03/04/2015] [Indexed: 02/03/2023]
Abstract
A 1983 Immunology Today rostrum hypothesized that each T cell has two recognition units: a T cell receptor (TCR) complex, which binds antigen associated with a polymorphic region of a MHC molecule (pMHC), and a CD4 or CD8 molecule that binds to a conserved region of that same MHC gene product (class II or I, respectively). Structural biology has since precisely revealed those bidentate pMHC interactions. TCRαβ ligates the membrane-distal antigen-binding MHC platform, whereas CD8 clamps a membrane-proximal MHCI α3 domain loop and CD4 docks to a hydrophobic crevice between MHCII α2 and β2 domains. Here, we review how MHC class-restricted binding impacts signaling and lineage commitment, discussing TCR force-driven conformational transitions that may optimally expose the co-receptor docking site on MHC.
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Affiliation(s)
- Ellis L Reinherz
- Laboratory of Immunobiology and Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115, USA; Department of Medicine, Harvard Medical School, Boston, MA 02115, USA.
| | - Jia-huai Wang
- Laboratory of Immunobiology and Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115, USA; Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA; Department of Biological Chemistry & Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA
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7
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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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8
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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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9
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Wang JH, Reinherz EL. The structural basis of αβ T-lineage immune recognition: TCR docking topologies, mechanotransduction, and co-receptor function. Immunol Rev 2012; 250:102-19. [PMID: 23046125 PMCID: PMC3694212 DOI: 10.1111/j.1600-065x.2012.01161.x] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Self versus non-self discrimination is at the core of T-lymphocyte recognition. To this end, αβ T-cell receptors (TCRs) ligate 'foreign' peptides bound to major histocompatibility complex (MHC) class I or class II molecules (pMHC) arrayed on the surface of antigen-presenting cells (APCs). Since the discovery of TCRs approximately 30 years ago, considerable structural and functional data have detailed the molecular basis of their extraordinary ligand specificity and sensitivity in mediating adaptive T-cell immunity. This review focuses on the structural biology of the Fab-like TCRαβ clonotypic heterodimer and its unique features in conjunction with those of the associated CD3εγ and CD3εδ heterodimeric molecules, which, along with CD3ζζ homodimer, comprise the TCR complex in a stoichiometry of 1:1:1:1. The basis of optimized TCRαβ docking geometry on the pMHC linked to TCR mechanotransduction and required for T-cell signaling as well as CD4 and CD8 co-receptor function is detailed. A model of the TCR ectodomain complex including its connecting peptides suggests how force generated during T-cell immune surveillance and at the immunological synapse results in dynamic TCR quaternary change involving its heterodimeric components. Potential insights from the structural biology relevant to immunity and immunosuppression are revealed.
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MESH Headings
- Animals
- Antigen-Presenting Cells/cytology
- Antigen-Presenting Cells/immunology
- Antigen-Presenting Cells/metabolism
- Antigens/chemistry
- Antigens/immunology
- Antigens/metabolism
- CD3 Complex/chemistry
- CD3 Complex/immunology
- CD3 Complex/metabolism
- CD4-Positive T-Lymphocytes/cytology
- CD4-Positive T-Lymphocytes/immunology
- CD4-Positive T-Lymphocytes/metabolism
- CD8-Positive T-Lymphocytes/cytology
- CD8-Positive T-Lymphocytes/immunology
- CD8-Positive T-Lymphocytes/metabolism
- Humans
- Major Histocompatibility Complex/immunology
- Mechanotransduction, Cellular
- Mice
- Models, Molecular
- Peptides/chemistry
- Peptides/immunology
- Peptides/metabolism
- Protein Conformation
- Protein Multimerization
- Receptors, Antigen, T-Cell, alpha-beta/chemistry
- Receptors, Antigen, T-Cell, alpha-beta/immunology
- Receptors, Antigen, T-Cell, alpha-beta/metabolism
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Affiliation(s)
- Jia-huai Wang
- Laboratory of Immunobiology and Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
- Department of Pediatrics, Harvard Medical School, Boston, MA, USA
- Department of Biological Chemistry & Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
| | - Ellis L. Reinherz
- Laboratory of Immunobiology and Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
- Department of Medicine, Harvard Medical School, Boston, MA, USA
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10
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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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11
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Kim ST, Touma M, Takeuchi K, Sun ZYJ, Dave VP, Kappes DJ, Wagner G, Reinherz EL. Distinctive CD3 heterodimeric ectodomain topologies maximize antigen-triggered activation of alpha beta T cell receptors. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2010; 185:2951-9. [PMID: 20660709 PMCID: PMC2936104 DOI: 10.4049/jimmunol.1000732] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The alphabeta TCR has recently been suggested to function as an anisotropic mechanosensor during immune surveillance, converting mechanical energy into a biochemical signal upon specific peptide/MHC ligation of the alphabeta clonotype. The heterodimeric CD3epsilongamma and CD3epsilondelta subunits, each composed of two Ig-like ectodomains, form unique side-to-side hydrophobic interfaces involving their paired G-strands, rigid connectors to their respective transmembrane segments. Those dimers are laterally disposed relative to the alphabeta heterodimer within the TCR complex. In this paper, using structure-guided mutational analysis, we investigate the functional consequences of a striking asymmetry in CD3gamma and CD3delta G-strand geometries impacting ectodomain shape. The uniquely kinked conformation of the CD3gamma G-strand is crucial for maximizing Ag-triggered TCR activation and surface TCR assembly/expression, offering a geometry to accommodate juxtaposition of CD3gamma and TCR beta ectodomains and foster quaternary change that cannot be replaced by the isologous CD3delta subunit's extracellular region. TCRbeta and CD3 subunit protein sequence analyses among Gnathostomata species show that the Cbeta FG loop and CD3gamma subunit coevolved, consistent with this notion. Furthermore, restoration of T cell activation and development in CD3gamma(-/-) mouse T lineage cells by interspecies replacement can be rationalized from structural insights on the topology of chimeric mouse/human CD3epsilondelta dimers. Most importantly, our findings imply that CD3gamma and CD3delta evolved from a common precursor gene to optimize peptide/MHC-triggered alphabeta TCR activation.
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MESH Headings
- Amino Acid Sequence
- Animals
- CD3 Complex/chemistry
- CD3 Complex/genetics
- CD3 Complex/physiology
- Evolution, Molecular
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Mice, Transgenic
- Molecular Sequence Data
- Organ Culture Techniques
- Protein Multimerization
- Protein Structure, Quaternary
- Protein Structure, Tertiary
- Receptors, Antigen, T-Cell, alpha-beta/metabolism
- Receptors, Antigen, T-Cell, alpha-beta/physiology
- Sheep
- Signal Transduction/genetics
- Signal Transduction/immunology
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Affiliation(s)
- Sun Taek Kim
- Laboratory of Immunobiology and Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115
- Department of Medicine, Harvard Medical School, Boston, MA 02115
| | - Maki Touma
- Laboratory of Immunobiology and Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115
- Department of Medicine, Harvard Medical School, Boston, MA 02115
| | - Koh Takeuchi
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115
| | - Zhen-Yu J. Sun
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115
| | - Vibhuti P. Dave
- Lymphocyte Development Laboratory, Clinical Research Institute of Montreal, Montreal, Quebec, Canada
| | - Dietmar J. Kappes
- Blood Cell Development and Cancer Program, Fox Chase Cancer Center, Philadelphia, PA 19111
| | - Gerhard Wagner
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115
| | - Ellis L. Reinherz
- Laboratory of Immunobiology and Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115
- Department of Medicine, Harvard Medical School, Boston, MA 02115
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12
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Kim ST, Takeuchi K, Sun ZYJ, Touma M, Castro CE, Fahmy A, Lang MJ, Wagner G, Reinherz EL. The alphabeta T cell receptor is an anisotropic mechanosensor. J Biol Chem 2009; 284:31028-37. [PMID: 19755427 PMCID: PMC2781503 DOI: 10.1074/jbc.m109.052712] [Citation(s) in RCA: 302] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2009] [Revised: 09/12/2009] [Indexed: 01/06/2023] Open
Abstract
Thymus-derived lymphocytes protect mammalian hosts against virus- or cancer-related cellular alterations through immune surveillance, eliminating diseased cells. In this process, T cell receptors (TCRs) mediate both recognition and T cell activation via their dimeric alphabeta, CD3 epsilon gamma, CD3 epsilon delta, and CD3 zeta zeta subunits using an unknown structural mechanism. Here, site-specific binding topology of anti-CD3 monoclonal antibodies (mAbs) and dynamic TCR quaternary change provide key clues. Agonist mAbs footprint to the membrane distal CD3 epsilon lobe that they approach diagonally, adjacent to the lever-like C beta FG loop that facilitates antigen (pMHC)-triggered activation. In contrast, a non-agonist mAb binds to the cleft between CD3 epsilon and CD3 gamma in a perpendicular mode and is stimulatory only subsequent to an external tangential but not a normal force ( approximately 50 piconewtons) applied via optical tweezers. Specific pMHC but not irrelevant pMHC activates a T cell upon application of a similar force. These findings suggest that the TCR is an anisotropic mechanosensor, converting mechanical energy into a biochemical signal upon specific pMHC ligation during immune surveillance. Activating anti-CD3 mAbs mimic this force via their intrinsic binding mode. A common TCR quaternary change rather than conformational alterations can better facilitate structural signal initiation, given the vast array of TCRs and their specific pMHC ligands.
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MESH Headings
- Animals
- Antibodies, Monoclonal/immunology
- CD3 Complex/immunology
- Cell Line
- Mechanotransduction, Cellular
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Molecular Conformation
- Protein Binding
- Receptors, Antigen, T-Cell, alpha-beta/chemistry
- Receptors, Antigen, T-Cell, alpha-beta/genetics
- Receptors, Antigen, T-Cell, alpha-beta/immunology
- Receptors, Antigen, T-Cell, alpha-beta/metabolism
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Affiliation(s)
- Sun Taek Kim
- From the Department of Medical Oncology, Laboratory of Immunobiology, Dana-Farber Cancer Institute and
- Departments of Medicine and
| | - Koh Takeuchi
- Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115 and
| | - Zhen-Yu J. Sun
- Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115 and
| | - Maki Touma
- From the Department of Medical Oncology, Laboratory of Immunobiology, Dana-Farber Cancer Institute and
- Departments of Medicine and
| | | | - Amr Fahmy
- Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115 and
| | - Matthew J. Lang
- the Departments of Mechanical Engineering and
- **Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - Gerhard Wagner
- Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115 and
| | - Ellis L. Reinherz
- From the Department of Medical Oncology, Laboratory of Immunobiology, Dana-Farber Cancer Institute and
- Departments of Medicine and
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13
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Yunis EJ, Zuniga J, Romero V, Yunis EJ. Chimerism and tetragametic chimerism in humans: implications in autoimmunity, allorecognition and tolerance. Immunol Res 2007; 38:213-36. [DOI: 10.1007/s12026-007-0013-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/1999] [Revised: 11/30/1999] [Accepted: 11/30/1999] [Indexed: 10/23/2022]
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14
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Primeau T, Myers NB, Yu YYL, Lybarger L, Wang X, Truscott SM, Hansen TH, Connolly JM. Applications of major histocompatibility complex class I molecules expressed as single chains. Immunol Res 2006; 32:109-21. [PMID: 16106063 DOI: 10.1385/ir:32:1-3:109] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Generation of CD8 T-cell responses to pathogens and tumors requires optimal expression of class I major histocompatibility complex/peptide complexes, which, in turn, is dependent on host cellular processing events and subject to interference by pathogens. To create a stable structure that is more immunogenic and resistant to immune evasion pathways, we have engineered class I molecules as single-chain trimers (SCTs), with flexible linkers connecting peptide, beta2m, and heavy chain. Herein we extend our earlier studies with SCTs to the K(b) ligand derived from vesicular stomatitis virus (VSV) to characterize further SCTs as probes of immune function as well as their potential in immunotherapy. The VSVp-beta2m-K(b) SCTs were remarkably stable at the cell surface, and immunization with DNA encoding SCTs elicited complex-specific antibody. In addition, SCTs were detected by cytotoxic T-lymphocytes specific for the native molecule, and the covalently bound peptide was highly resistant to displacement by exogenous peptide. SCTs can also prime CD8 T-cells in vivo that recognize the native molecule. Furthermore, SCTs were resistant to downregulation by the immune evasion protein mK3 of gamma herpesvirus 68. Moreover, owing to their preassembled nature, SCTs should be resistant to other immune evasion proteins that restrict peptide supply. Thus, SCTs possess therapeutic potential both for prophylactic treatment and for the treatment of ongoing infection.
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Affiliation(s)
- Tina Primeau
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA
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15
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Bordner AJ, Abagyan R. Ab initio prediction of peptide-MHC binding geometry for diverse class I MHC allotypes. Proteins 2006; 63:512-26. [PMID: 16470819 DOI: 10.1002/prot.20831] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Since determining the crystallographic structure of all peptide-MHC complexes is infeasible, an accurate prediction of the conformation is a critical computational problem. These models can be useful for determining binding energetics, predicting the structures of specific ternary complexes with T-cell receptors, and designing new molecules interacting with these complexes. The main difficulties are (1) adequate sampling of the large number of conformational degrees of freedom for the flexible peptide, (2) predicting subtle changes in the MHC interface geometry upon binding, and (3) building models for numerous MHC allotypes without known structures. Whereas previous studies have approached the sampling problem by dividing the conformational variables into different sets and predicting them separately, we have refined the Biased-Probability Monte Carlo docking protocol in internal coordinates to optimize a physical energy function for all peptide variables simultaneously. We also imitated the induced fit by docking into a more permissive smooth grid representation of the MHC followed by refinement and reranking using an all-atom MHC model. Our method was tested by a comparison of the results of cross-docking 14 peptides into HLA-A*0201 and 9 peptides into H-2K(b) as well as docking peptides into homology models for five different HLA allotypes with a comprehensive set of experimental structures. The surprisingly accurate prediction (0.75 A backbone RMSD) for cross-docking of a highly flexible decapeptide, dissimilar to the original bound peptide, as well as docking predictions using homology models for two allotypes with low average backbone RMSDs of less than 1.0 A illustrate the method's effectiveness. Finally, energy terms calculated using the predicted structures were combined with supervised learning on a large data set to classify peptides as either HLA-A*0201 binders or nonbinders. In contrast with sequence-based prediction methods, this model was also able to predict the binding affinity for peptides to a different MHC allotype (H-2K(b)), not used for training, with comparable prediction accuracy.
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Affiliation(s)
- Andrew J Bordner
- Department of Molecular Biology, The Scripps Research Institute, San Diego, California, USA.
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16
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Achour A, Michaëlsson J, Harris RA, Ljunggren HG, Kärre K, Schneider G, Sandalova T. Structural basis of the differential stability and receptor specificity of H-2Db in complex with murine versus human beta2-microglobulin. J Mol Biol 2005; 356:382-96. [PMID: 16375919 DOI: 10.1016/j.jmb.2005.11.068] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2005] [Revised: 11/07/2005] [Accepted: 11/22/2005] [Indexed: 11/15/2022]
Abstract
beta(2)-Microglobulin (beta(2)m) is non-covalently linked to the major histocompatibility complex (MHC) class I heavy chain and interacts with CD8 and Ly49 receptors. Murine MHC class I heavy chains can bind human beta(2)m (hbeta(2)m) and peptide, and such hybrid molecules are often used in structural and functional studies. The replacement of mouse beta(2)m (mbeta(2)m) with hbeta(2)m has several functional consequences for MHC class I complex stability and specificity, but the structural basis for this is presently unknown. To investigate the impact of species-specific beta(2)m subunits on MHC class I conformation, we provide a crystallographic comparison of H-2D(b) in complex with LCMV-derived gp33 peptide and either hbeta(2)m or mbeta(2)m. The conformation of the gp33 peptide is not affected by the beta(2)m species. Comparison of the interface between beta(2)m and the alpha(1)alpha(2) domains of the heavy chain in these two crystal structures reveals a marked increase in both polarity and number of hydrogen bonds between hbeta(2)m and the alpha(1)alpha(2) domains of H-2D(b). We propose that the positioning of two hydrogen bond rich regions at the hbeta(2)m/alpha(1)alpha(2) interface plays a central role in the increased overall stability and peptide exchange capacity in the H-2D(b)/hbeta(2)m complex. These two regions act as bridges, holding and stabilizing the underside of the alpha(1) and alpha(2) helices, enabling a prolonged peptide-receptive conformation of the peptide binding cleft. Furthermore, analysis of H-2D(b) in complex with either mbeta(2)m or hbeta(2)m provides a structural explanation for the differential binding of H-2D(b)/hbeta(2)m to both Ly49A and Ly49C. Our comparative structural study emphasizes the importance of beta(2)m residues at positions 3, 6 and 29 for binding to Ly49A and suggests that sterical hindrance by residue K6 on hbeta(2)m impairs the recognition of Ly49C by H-2D(b)/gp33/hbeta(2)m. Finally, comparison of the two H-2D(b) crystal structures implies that the beta(2)m species may affect the strength of TCR recognition by affecting CD8 binding.
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Affiliation(s)
- Adnane Achour
- Center for Infectious Medicine, F59, Department of Medicine, Karolinska Institutet, Karolinska University Hospital in Huddinge, Stockholm, Sweden.
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17
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Fagerberg T, Cerottini JC, Michielin O. Structural prediction of peptides bound to MHC class I. J Mol Biol 2005; 356:521-46. [PMID: 16368108 DOI: 10.1016/j.jmb.2005.11.059] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2005] [Revised: 11/16/2005] [Accepted: 11/17/2005] [Indexed: 11/29/2022]
Abstract
An ab initio structure prediction approach adapted to the peptide-major histocompatibility complex (MHC) class I system is presented. Based on structure comparisons of a large set of peptide-MHC class I complexes, a molecular dynamics protocol is proposed using simulated annealing (SA) cycles to sample the conformational space of the peptide in its fixed MHC environment. A set of 14 peptide-human leukocyte antigen (HLA) A0201 and 27 peptide-non-HLA A0201 complexes for which X-ray structures are available is used to test the accuracy of the prediction method. For each complex, 1000 peptide conformers are obtained from the SA sampling. A graph theory clustering algorithm based on heavy atom root-mean-square deviation (RMSD) values is applied to the sampled conformers. The clusters are ranked using cluster size, mean effective or conformational free energies, with solvation free energies computed using Generalized Born MV 2 (GB-MV2) and Poisson-Boltzmann (PB) continuum models. The final conformation is chosen as the center of the best-ranked cluster. With conformational free energies, the overall prediction success is 83% using a 1.00 Angstroms crystal RMSD criterion for main-chain atoms, and 76% using a 1.50 Angstroms RMSD criterion for heavy atoms. The prediction success is even higher for the set of 14 peptide-HLA A0201 complexes: 100% of the peptides have main-chain RMSD values < or =1.00 Angstroms and 93% of the peptides have heavy atom RMSD values < or =1.50 Angstroms. This structure prediction method can be applied to complexes of natural or modified antigenic peptides in their MHC environment with the aim to perform rational structure-based optimizations of tumor vaccines.
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Affiliation(s)
- Theres Fagerberg
- Ludwig Institute for Cancer Research, University of Lausanne, Epalinges, Switzerland
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18
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Vukmanović S, Santori FR. Self-peptide/MHC and TCR antagonism: physiological role and therapeutic potential. Cell Immunol 2005; 233:75-84. [PMID: 15950208 DOI: 10.1016/j.cellimm.2005.04.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2005] [Accepted: 04/21/2005] [Indexed: 10/25/2022]
Abstract
TCR antagonists are peptides that bind MHC molecules and can specifically inhibit T cell activation induced by antigens. Studying TCR antagonism has taken an important place in immunology for both theoretical and practical reasons. Deciphering the mechanism(s) of action of TCR antagonists can yield important information about interactions of the TCR with ligands, T cell development, and TCR signaling. Moreover, microorganisms may employ TCR antagonism to elude the attention of the immune system. Finally, specificity of inhibition makes TCR antagonists an ideal tool to seek antigen-specific immunomodulation. Present state of knowledge on these topics is reviewed.
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Affiliation(s)
- Stanislav Vukmanović
- Center for Cancer and Immunology Research, Children's Research Institute, Children's National Medical Center, 111 Michigan Avenue NW, Washington, DC 20010-2970, USA.
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19
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Fridkis-Hareli M, Reinherz EL. New approaches to eliciting protective immunity through T cell repertoire manipulation: the concept of thymic vaccination. MEDICAL IMMUNOLOGY (LONDON, ENGLAND) 2004; 3:2. [PMID: 15588284 PMCID: PMC544398 DOI: 10.1186/1476-9433-3-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/03/2004] [Accepted: 12/08/2004] [Indexed: 12/24/2022]
Abstract
Conventional vaccines afford protection against infectious diseases by expanding existing pathogen-specific peripheral lymphocytes, both CD8 cytotoxic effector (CTL) and CD4 helper T cells. The latter induce B cell maturation and antibody production. As a consequence, lymphocytes within the memory pool are poised to rapidly proliferate at the time of a subsequent infection. The "thymic vaccination" concept offers a novel way to alter the primary T cell repertoire through exposure of thymocytes to altered peptide ligands (APL) with reduced T cell receptor (TCR) affinity relative to cognate antigens recognized by those same TCRs. Thymocyte maturation (i.e. positive selection) is enhanced by low affinity interaction between a TCR and an MHC-bound peptide in the thymus and subsequent emigration of mature cells into the peripheral T lymphocyte pool follows. In principal, such variants of antigens derived from infectious agents could be utilized for peptide-driven maturation of thymocytes bearing pathogen-specific TCRs. To test this idea, APLs of gp33-41, a Db-restricted peptide derived from the lymphocytic choriomeningitis virus (LCMV) glycoprotein, and of VSV8, a Kb-restricted peptide from the vesicular stomatitis virus (VSV) nucleoprotein, have been designed and their influence on thymic maturation of specific TCR-bearing transgenic thymocytes examined in vivo using irradiation chimeras. Injection of APL resulted in positive selection of CD8 T cells expressing the relevant viral specificity and in the export of those virus-specific CTL to lymph nodes without inducing T cell proliferation. Thus, exogenous APL administration offers the potential of expanding repertoires in vivo in a manner useful to the organism. To efficiently peripheralize antigen-specific T cells, concomitant enhancement of mechanisms promoting thymocyte migration appears to be required. This commentary describes the rationale for thymic vaccination and addresses the potential prophylactic and therapeutic applications of this approach for treatment of infectious diseases and cancer. Thymic vaccination-induced peptide-specific T cells might generate effective immune protection against disease-causing agents, including those for which no effective natural protection exists.
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Affiliation(s)
- Masha Fridkis-Hareli
- Laboratory of Immunobiology, Department of Medical Oncology, Dana-Farber Cancer Institute, USA
- Department of Medicine, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, MA 02115, USA
| | - Ellis L Reinherz
- Laboratory of Immunobiology, Department of Medical Oncology, Dana-Farber Cancer Institute, USA
- Department of Medicine, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, MA 02115, USA
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20
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Santori FR, Holmberg K, Ostrov D, Gascoigne NRJ, Vukmanović S. Distinct footprints of TCR engagement with highly homologous ligands. THE JOURNAL OF IMMUNOLOGY 2004; 172:7466-75. [PMID: 15187125 DOI: 10.4049/jimmunol.172.12.7466] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
T cell receptor engagement promotes proliferation, differentiation, survival, or death of T lymphocytes. The affinity/avidity of the TCR ligand and the maturational stage of the T cell are thought to be principal determinants of the outcome of TCR engagement. We demonstrate in this study that the same mouse TCR preferentially uses distinct residues of homologous peptides presented by the MHC molecules to promote specific cellular responses. The preference for distinct TCR contacts depends on neither the affinity/avidity of TCR engagement (except in the most extreme ranges), nor the maturity of engaged T cells. Thus, different portions of the TCR ligand appear capable of biasing T cells toward specific biological responses. These findings explain differences in functional versatility of TCR ligands, as well as anomalies in the relationship between affinity/avidity of the TCR for the peptide/MHC and cellular responses of T cells.
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MESH Headings
- Amino Acid Sequence
- Animals
- Antigen Presentation
- Epitope Mapping
- Epitopes, T-Lymphocyte/chemistry
- Epitopes, T-Lymphocyte/physiology
- Ligands
- Mice
- Mice, Transgenic
- Models, Molecular
- Peptides/chemical synthesis
- Peptides/immunology
- Protein Binding
- Protein Footprinting
- Receptors, Antigen, T-Cell/genetics
- Receptors, Antigen, T-Cell/metabolism
- Receptors, Antigen, T-Cell/physiology
- Structure-Activity Relationship
- T-Lymphocyte Subsets
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Affiliation(s)
- Fabio R Santori
- Michael Heidelberger Division of Immunology, Department of Pathology and New York University Cancer Center, New York University School of Medicine, New York, NY 10016, USA
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21
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Fridkis-Hareli M, Reche PA, Reinherz EL. Peptide variants of viral CTL epitopes mediate positive selection and emigration of Ag-specific thymocytes in vivo. THE JOURNAL OF IMMUNOLOGY 2004; 173:1140-50. [PMID: 15240703 DOI: 10.4049/jimmunol.173.2.1140] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
During development, thymocytes carrying TCRs mediating low-affinity interactions with MHC-bound self-peptides are positively selected for export into the mature peripheral T lymphocyte pool. Thus, exogenous administration of certain altered peptide ligands (APL) with reduced TCR affinity relative to cognate Ags may provide a tool to elicit maturation of desired TCR specificities. To test this "thymic vaccination" concept, we designed APL of the viral CTL epitopes gp33-41 and vesicular stomatitis virus nucleoprotein octapeptide N52-59 relevant for the lymphocytic choriomeningitis virus-specific P14- and vesicular stomatitis virus-specific N15-TCRs, respectively, and examined their effects on thymocytes in vivo using irradiation chimeras. Injection of APL into irradiated congenic (Ly-5.1) mice, reconstituted with T cell progenitors from the bone marrow of P14 RAG2(-/-) (Ly-5.2) or N15 RAG2(-/-) (Ly-5.2) transgenic mice, resulted in positive selection of T cells expressing the relevant specificity. Moreover, the variants led to export of virus-specific T cells to lymph nodes, but without inducing T cell proliferation. These findings show that the mature T cell repertoire can be altered by in vivo peptide administration through manipulation of thymic selection.
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Affiliation(s)
- Masha Fridkis-Hareli
- Laboratory of Immunobiology, Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02115, USA
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22
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Kessels HWHG, de Visser KE, Tirion FH, Coccoris M, Kruisbeek AM, Schumacher TNM. The impact of self-tolerance on the polyclonal CD8+ T cell repertoire. THE JOURNAL OF IMMUNOLOGY 2004; 172:2324-31. [PMID: 14764701 DOI: 10.4049/jimmunol.172.4.2324] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
TCRs possess considerable cross-reactivity toward structurally related Ags. Because the signaling threshold for negative selection is lower than that required for activation of mature T cells, the question arises as to which extent thymic deletion of self-specific T cells affects T cell responsiveness toward foreign peptides. In this study we show, in three different mouse models systems, that the polyclonal CD8(+) T cell repertoire has a marked ability to react against the majority of Ags related to self despite self-tolerance, even in cases where self and foreign differ only marginally at a single TCR-contact residue. Thus, while individual T cells are markedly cross-reactive, the ability to distinguish between closely related Ags is introduced at the polyclonal T cell level.
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Affiliation(s)
- Helmut W H G Kessels
- Department of Immunology, The Netherlands Cancer Institute, Amsterdam, The Netherlands
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23
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Hillig RC, Hülsmeyer M, Saenger W, Welfle K, Misselwitz R, Welfle H, Kozerski C, Volz A, Uchanska-Ziegler B, Ziegler A. Thermodynamic and Structural Analysis of Peptide- and Allele-dependent Properties of Two HLA-B27 Subtypes Exhibiting Differential Disease Association. J Biol Chem 2004; 279:652-63. [PMID: 14555655 DOI: 10.1074/jbc.m307457200] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Selected HLA-B27 subtypes are associated with spondyloarthropathies, but the underlying mechanism is not understood. To explain this association in molecular terms, a comparison of peptide-dependent dynamic and structural properties of the differentially disease-associated subtypes HLA-B*2705 and HLA-B*2709 was carried out. These molecules differ only by a single amino acid at the floor of the peptide binding groove. The thermostabilities of a series of HLA-B27 molecules complexed with nonameric and decameric peptides were determined and revealed substantial differences depending on the subtype as well as the residues at the termini of the peptides. In addition we present the crystal structure of the B*2709 subtype complexed with a decameric peptide. This structure provides an explanation for the preference of HLA-B27 for a peptide with an N-terminal arginine as secondary anchor and the lack of preference for tyrosine as peptide C terminus in B*2709. The data show that differences in thermodynamic properties between peptide-complexed HLA-B27 subtypes are correlated with a variety of structural properties.
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Affiliation(s)
- Roman C Hillig
- Institut für Immungenetik, Charité, Humboldt-Universität zu Berlin, Spandauer Damm 130, 14050 Berlin, Germany
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24
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Wang Z, Turner R, Baker BM, Biddison WE. MHC allele-specific molecular features determine peptide/HLA-A2 conformations that are recognized by HLA-A2-restricted T cell receptors. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2002; 169:3146-54. [PMID: 12218132 DOI: 10.4049/jimmunol.169.6.3146] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The structures of alphabeta TCRs bound to complexes of class I MHC molecules and peptide show that the TCRs make multiple contacts with the alpha1 and alpha2 helixes of the MHC. Previously we have shown that the A6 TCR in complex with the HLA-A2/Tax peptide has 15 contact sites on HLA-A2. Single amino acid mutagenesis of these contact sites demonstrated that mutation of only three amino acids clustered on the alpha1 helix (R65, K66, A69) disrupted recognition by the A6 TCR. In the present study we have asked whether TCRs that recognize four other peptides presented by HLA-A2 interact with the MHC in identical, similar, or different patterns as the A6 TCR. Mutants K66A and Q155A had the highest frequency of negative effects on lysis. A subset of peptide-specific CTL also selectively recognized mutants K66A or Q155A in the absence of exogenous cognate peptides, indicating that these mutations affected the presentation of endogenous peptide/HLA-A2 complexes. These findings suggest that most HLA-A2-restricted TCRs recognize surfaces on the HLA-A2/peptide complex that are dependent upon the side chains of K66 and Q155 in the central portion of the peptide binding groove. Crystallographic structures of several peptide/HLA-A2 structures have shown that the side chains of these critical amino acids that make contact with the A6 TCR also contact the bound peptide. Collectively, our results indicate that the generalized effects of changes at these critical amino acids are probably due to the fact that they can be directly contacted by TCRs as well as influence the binding and presentation of the bound peptides.
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Affiliation(s)
- Zichun Wang
- Molecular Immunology Section, Neuroimmunology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
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25
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Santori FR, Kieper WC, Brown SM, Lu Y, Neubert TA, Johnson KL, Naylor S, Vukmanović S, Hogquist KA, Jameson SC. Rare, structurally homologous self-peptides promote thymocyte positive selection. Immunity 2002; 17:131-42. [PMID: 12196285 DOI: 10.1016/s1074-7613(02)00361-8] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Although it is clear that positive selection of T cells involves recognition of specific self-peptide/MHC complexes, the nature of these self-ligands and their relationship to the cognate antigen are controversial. Here we used two complementary strategies to identify naturally occurring self-peptides able to induce positive selection of T cells bearing a specific T cell receptor, OT-I. Both the bioassay- and bioinformatics-based strategies identified the same self-peptides, derived from F-actin capping protein and beta-catenin. These peptides displayed charge conservation at two key TCR contact residues. The biological activity of 43 other self-peptides and of complex peptide libraries directly correlated to the extent of conservation at TCR contact residues. These results demonstrate that selecting self-peptides are rare and can be identified by homology-based search strategies.
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Affiliation(s)
- Fabio R Santori
- Michael Heidelberger Division of Immunology, Department of Pathology and Kaplan Cancer Center, New York University School of Medicine, 550 First Avenue, NY 10016, USA
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26
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Sasada T, Touma M, Chang HC, Clayton LK, Wang JH, Reinherz EL. Involvement of the TCR Cbeta FG loop in thymic selection and T cell function. J Exp Med 2002; 195:1419-31. [PMID: 12045240 PMCID: PMC2193539 DOI: 10.1084/jem.20020119] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2002] [Revised: 03/29/2002] [Accepted: 04/15/2002] [Indexed: 11/21/2022] Open
Abstract
The asymmetric disposition of T cell receptor (TCR) Cbeta and Calpha ectodomains creates a cavity with a side-wall formed by the rigid Cbeta FG loop. To investigate the significance of this conserved structure, we generated loop deletion (betaDeltaFG) and betawt transgenic (tg) mice using the TCR beta subunit of the N15 CTL. N15betawt and N15betaDeltaFG H-2(b) animals have comparable numbers of thymocytes in S phase and manifest developmental progression through the CD4(-)CD8(-) double-negative (DN) compartment. N15betaDeltaFG facilitates transition from DN to CD4(+)8(+) double-positive (DP) thymocytes in recombinase activating gene (RAG)-2(-/-) mice, showing that pre-TCR function remains. N15betaDeltaFG animals possess approximately twofold more CD8(+) single-positive (SP) thymocytes and lymph node T cells, consistent with enhanced positive selection. As an altered Valpha repertoire observed in N15betaDeltaFG mice may confound the deletion's effect, we crossed N15alphabeta TCR tg RAG-2(-/-) with N15betaDeltaFG tg RAG-2(-/-) H-2(b) mice to generate N15alphabeta RAG-2(-/-) and N15alphabeta.betaDeltaFG RAG-2(-/-) littermates. N15alphabeta.betaDeltaFG RAG-2(-/-) mice show an 8-10-fold increase in DP thymocytes due to reduced negative selection, as evidenced by diminished constitutive and cognate peptide-induced apoptosis. Compared with N15alphabeta, N15alphabeta.betaDeltaFG T cells respond poorly to cognate antigens and weak agonists. Thus, the Cbeta FG loop facilitates negative selection of thymocytes and activation of T cells.
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MESH Headings
- Amino Acid Sequence
- Animals
- Apoptosis
- Cattle
- Cell Division
- Cell Lineage
- Cytokines/metabolism
- Dogs
- Flow Cytometry
- Humans
- Interferon-gamma/metabolism
- Lymph Nodes/cytology
- Mice
- Mice, Transgenic
- Models, Molecular
- Molecular Sequence Data
- Protein Conformation
- Rabbits
- Rats
- Receptors, Antigen, T-Cell, alpha-beta/chemistry
- Receptors, Antigen, T-Cell, alpha-beta/genetics
- Receptors, Antigen, T-Cell, alpha-beta/metabolism
- Sequence Homology, Amino Acid
- T-Lymphocytes/cytology
- T-Lymphocytes/immunology
- T-Lymphocytes/metabolism
- Thymus Gland/cytology
- Thymus Gland/immunology
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Affiliation(s)
- Tetsuro Sasada
- Laboratory of Immunobiology, Dana-Farber Cancer Institute, 44 Binney Street, Boston, MA 02115
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27
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Adrian PEH, Rajaseger G, Mathura VS, Sakharkar MK, Kangueane P. Types of inter-atomic interactions at the MHC-peptide interface: identifying commonality from accumulated data. BMC STRUCTURAL BIOLOGY 2002; 2:2. [PMID: 12010576 PMCID: PMC113755 DOI: 10.1186/1472-6807-2-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/11/2001] [Accepted: 05/13/2002] [Indexed: 11/10/2022]
Abstract
BACKGROUND Quantitative information on the types of inter-atomic interactions at the MHC-peptide interface will provide insights to backbone/sidechain atom preference during binding. Qualitative descriptions of such interactions in each complex have been documented by protein crystallographers. However, no comprehensive report is available to account for the common types of inter-atomic interactions in a set of MHC-peptide complexes characterized by variation in MHC allele and peptide sequence. The available x-ray crystallography data for these complexes in the Protein Databank (PDB) provides an opportunity to identify the prevalent types of such interactions at the binding interface. RESULTS We calculated the percentage distributions of four types of interactions at varying inter-atomic distances. The mean percentage distribution for these interactions and their standard deviation about the mean distribution is presented. The prevalence of SS and SB interactions at the MHC-peptide interface is shown in this study. SB is clearly dominant at an inter-atomic distance of 3A. CONCLUSION The prevalently dominant SB interactions at the interface suggest the importance of peptide backbone conformation during MHC-peptide binding. Currently, available algorithms are developed for protein sidechain prediction upon fixed backbone template. This study shows the preference of backbone atoms in MHC-peptide binding and hence emphasizes the need for accurate peptide backbone prediction in quantitative MHC-peptide binding calculations.
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Affiliation(s)
- Png Eak Hock Adrian
- National University of Singapore, Department of Microbiology, Medical Drive, Singapore.
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28
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Abstract
Helper T lymphocytes play a critical role in immune system activation following recognition of MHC class II-bound peptide ligands (pMHCII). These CD4 T cells stimulate B cell antibody production and cytolytic T cell generation. Until recently, the structural basis of coordinate T cell receptor (TCR) and CD4 co-receptor interaction with a given pMHCII was unknown. Here we review current structural data on specific pMHCII recognition by T cells and compare TCR and co-receptor docking to pMHCI versus pMHCII ligands. The implications of these findings for thymic selection, helper versus cytolytic T cell recognition and alloreactivity are discussed.
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Affiliation(s)
- Jia-huai Wang
- Laboratory of Immunobiology, Dana-Farber Cancer Institute, 44 Binney Street, Boston, MA 02115, USA.
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29
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Fiorini E, Schmitz I, Marissen WE, Osborn SL, Touma M, Sasada T, Reche PA, Tibaldi EV, Hussey RE, Kruisbeek AM, Reinherz EL, Clayton LK. Peptide-induced negative selection of thymocytes activates transcription of an NF-kappa B inhibitor. Mol Cell 2002; 9:637-48. [PMID: 11931770 DOI: 10.1016/s1097-2765(02)00469-0] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Negative selection eliminates thymocytes bearing autoreactive T cell receptors (TCR) via an apoptotic mechanism. We have cloned an inhibitor of NF-kappa B, I kappa BNS, which is rapidly expressed upon TCR-triggered but not dexamethasone- or gamma irradiation-stimulated thymocyte death. The predicted protein contains seven ankyrin repeats and is homologous to I kappa B family members. In class I and class II MHC-restricted TCR transgenic mice, transcription of I kappa BNS is stimulated by peptides that trigger negative selection but not by those inducing positive selection (i.e., survival) or nonselecting peptides. I kappa BNS blocks transcription from NF-kappa B reporters, alters NF-kappa B electrophoretic mobility shifts, and interacts with NF-kappa B proteins in thymic nuclear lysates following TCR stimulation. Retroviral transduction of I kappa BNS in fetal thymic organ culture enhances TCR-triggered cell death consistent with its function in selection.
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Affiliation(s)
- Emma Fiorini
- Laboratory of Immunobiology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115, USA
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30
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Zhang W, Honda S, Wang F, DiLorenzo TP, Kalergis AM, Ostrov DA, Nathenson SG. Immunobiological analysis of TCR single-chain transgenic mice reveals new possibilities for interaction between CDR3alpha and an antigenic peptide bound to MHC class I. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2001; 167:4396-404. [PMID: 11591764 DOI: 10.4049/jimmunol.167.8.4396] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The interaction between TCRs and peptides presented by MHC molecules determines the specificity of the T cell-mediated immune response. To elucidate the biologically important structural features of this interaction, we generated TCR beta-chain transgenic mice using a TCR derived from a T cell clone specific for the immunodominant peptide of vesicular stomatitis virus (RGYVYQGL, VSV8) presented by H-2K(b). We immunized these mice with VSV8 or analogs substituted at TCR contact residues (positions 1, 4, and 6) and analyzed the CDR3alpha sequences of the elicited T cells. In VSV8-specific CTLs, we observed a highly conserved residue at position 93 of CDR3alpha and preferred Jalpha usage, indicating that multiple residues of CDR3alpha are critical for recognition of the peptide. Certain substitutions at peptide position 4 induced changes at position 93 and in Jalpha usage, suggesting a potential interaction between CDR3alpha and position 4. Cross-reactivity data revealed the foremost importance of the Jalpha region in determining Ag specificity. Surprisingly, substitution at position 6 of VSV8 to a negatively charged residue induced a change at position 93 of CDR3alpha to a positively charged residue, suggesting that CDR3alpha may interact with position 6 in certain circumstances. Analogous interactions between the TCR alpha-chain and residues in the C-terminal half of the peptide have not yet been revealed by the limited number of TCR/peptide-MHC crystal structures reported to date. The transgenic mouse approach allows hundreds of TCR/peptide-MHC interactions to be examined comparatively easily, thus permitting a wide-ranging analysis of the possibilities for Ag recognition in vivo.
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MESH Headings
- Amino Acid Sequence
- Animals
- Antigen Presentation
- Antigens, Viral/immunology
- Complementarity Determining Regions/metabolism
- Conserved Sequence
- Genes, T-Cell Receptor beta
- H-2 Antigens/metabolism
- Immunodominant Epitopes/immunology
- Mice
- Mice, Transgenic
- Models, Molecular
- Oligopeptides/immunology
- Peptide Fragments/immunology
- Protein Binding
- Receptors, Antigen, T-Cell, alpha-beta/genetics
- Receptors, Antigen, T-Cell, alpha-beta/metabolism
- T-Lymphocytes, Cytotoxic
- Vesicular stomatitis Indiana virus/immunology
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Affiliation(s)
- W Zhang
- Department of Cell Biology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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31
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Sasada T, Ghendler Y, Neveu JM, Lane WS, Reinherz EL. A naturally processed mitochondrial self-peptide in complex with thymic MHC molecules functions as a selecting ligand for a viral-specific T cell receptor. J Exp Med 2001; 194:883-92. [PMID: 11581311 PMCID: PMC2193488 DOI: 10.1084/jem.194.7.883] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Peptide fragments of self-proteins bound to major histocompatibility complex molecules within the thymus are important for positively selecting T cell receptor (TCR)-bearing CD4(+)CD8(+) double positive (DP) thymocytes for further maturation. The relationship between naturally processed thymic self-peptides and TCR-specific cognate peptides is unknown. Here we employ HPLC purification of peptides released from H-2K(b) molecules of the C57BL/6 thymus in conjunction with mass spectrometry (MS) and functional profiling to identify a naturally processed K(b)-bound peptide positively selecting the N15 TCR specific for the vesicular stomatitis virus octapeptide (VSV8) bound to K(b). The selecting peptide was identified in 1 of 80 HPLC fractions and shown by tandem MS (MS/MS) sequencing to correspond to residues 68-75 of the MLRQ subunit of the widely expressed mitochondrial NADH ubiquinone oxidoreductase (NUbO(68-75)). Of note, the peptide differs at six of its eight residues from the cognate peptide VSV8 and functions as a weak agonist for mature CD8 single positive (SP) N15 T cells, with activity 10,000-fold less than VSV8. In N15 transgenic (tg) recombinase activating gene 2(-/)- transporter associated with antigen processing 1(-/)- fetal thymic organ culture, NUbO(68-75) induces phenotypic and functional differentiation of N15 TCR bearing CD8 SP thymocytes. Failure of NUbO(68-75) to support differentiation of a second K(b)-restricted TCR indicates that its inductive effects are not general.
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Affiliation(s)
- Tetsuro Sasada
- Laboratory of Immunobiology and Department of Cancer Immunology & AIDS, Dana-Farber Cancer Institute and Department of Medicine, Harvard Medical School, Boston, MA 02115
| | - Yoseph Ghendler
- Laboratory of Immunobiology and Department of Cancer Immunology & AIDS, Dana-Farber Cancer Institute and Department of Medicine, Harvard Medical School, Boston, MA 02115
| | - John M. Neveu
- Microchemistry and Proteomics Analysis Facility, Harvard University, Cambridge, MA 02138
| | - William S. Lane
- Microchemistry and Proteomics Analysis Facility, Harvard University, Cambridge, MA 02138
| | - Ellis L. Reinherz
- Laboratory of Immunobiology and Department of Cancer Immunology & AIDS, Dana-Farber Cancer Institute and Department of Medicine, Harvard Medical School, Boston, MA 02115
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32
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Sun ZJ, Kim KS, Wagner G, Reinherz EL. Mechanisms contributing to T cell receptor signaling and assembly revealed by the solution structure of an ectodomain fragment of the CD3 epsilon gamma heterodimer. Cell 2001; 105:913-23. [PMID: 11439187 DOI: 10.1016/s0092-8674(01)00395-6] [Citation(s) in RCA: 148] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The T cell receptor (TCR) consists of genetically diverse disulfide-linked alpha and beta chains in noncovalent association with the invariant CD3 subunits. CD3 epsilon and CD3 gamma are integral components of both the TCR and pre-TCR. Here, we present the solution structure of a heterodimeric CD3 epsilon gamma ectodomain complex. A unique side-to-side hydrophobic interface between the two C2-set immunoglobulin-like domains and parallel pairing of their respective C-terminal beta strands are revealed. Mutational analysis confirms the importance of the distinctive linkage as well as the membrane proximal stalk motif (RxCxxCxE) for domain-domain association. These biochemical and structural analyses offer insights into the modular pairwise association of CD3 invariant chains. More importantly, the findings suggest how the rigidified CD3 elements participate in TCR-based signal transduction.
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Affiliation(s)
- Z J Sun
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA
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33
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Abstract
The exponentially increased sequence information on major histocompatibility complex (MHC) alleles points to the existence of a high degree of polymorphism within them. To understand the functional consequences of MHC alleles, 36 nonredundant MHC-peptide complexes in the protein data bank (PDB) were examined. Induced fit molecular recognition patterns such as those in MHC-peptide complexes are governed by numerous rules. The 36 complexes were clustered into 19 subgroups based on allele specificity and peptide length. The subgroups were further analyzed for identifying common features in MHC-peptide binding pattern. The four major observations made during the investigation were: (1) the positional preference of peptide residues defined by percentage burial upon complex formation is shown for all the 19 subgroups and the burial profiles within entries in a given subgroup are found to be similar; (2) in class I specific 8- and 9-mer peptides, the fourth residue is consistently solvent exposed, however this observation is not consistent in class I specific 10-mer peptides; (3) an anchor-shift in positional preference is observed towards the C terminal as the peptide length increases in class II specific peptides; and (4) peptide backbone atoms are proportionately dominant at the MHC-peptide interface.
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Affiliation(s)
- P Kangueane
- BioInformatics Centre, National University of Singapore, Singapore.
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34
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Thomson CT, Kalergis AM, Sacchettini JC, Nathenson SG. A structural difference limited to one residue of the antigenic peptide can profoundly alter the biological outcome of the TCR-peptide/MHC class I interaction. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2001; 166:3994-7. [PMID: 11238645 DOI: 10.4049/jimmunol.166.6.3994] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The vesicular stomatitis virus (VSV) octapeptide RGYVYQGL binds to H-2K(b) and triggers a cytotoxic T cell response in mice. A variant peptide, RGYVYEGL (E6) with a glutamic acid for glutamine replacement at position 6 of the VSV peptide, elicits a T cell response with features that are quite different from those elicited by the wild-type VSV peptide. The differences found in the nature of the T cells responding to the E6 peptide include changes in both the V beta elements and the sequences of the complementarity-determining region 3 loops of their TCRs. Further experiments found that the E6 peptide can act as an antagonist for VSV-specific T cell hybridomas. To determine whether these differences in V beta usage, complementarity-determining region 3 sequences, and the switch from agonism to antagonism are caused by a conformational change on the MHC, the peptide, or both, we determined the crystal structure of the variant E6 peptide bound to H-2K(b). This structure shows that the only significant structural difference between H-2K(b)/E6 and the previously determined H-2K(b)/VSV is limited to the side chain of position 6 of the peptide, with no differences in the MHC molecule. Thus, a minor conformational change in the peptide can profoundly alter the biological outcome of the TCR-peptide/MHC interaction.
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Affiliation(s)
- C T Thomson
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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35
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Xiong Y, Kern P, Chang H, Reinherz E. T Cell Receptor Binding to a pMHCII Ligand Is Kinetically Distinct from and Independent of CD4. J Biol Chem 2001; 276:5659-67. [PMID: 11106664 DOI: 10.1074/jbc.m009580200] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Immune recognition of pMHCII ligands by a helper T lymphocyte involves its antigen-specific T cell receptor (TCR) and CD4 coreceptor. We have characterized the binding of both molecules to the same pMHCII. The D10 alphabeta TCR heterodimer binds to conalbumin/I-A(k) with virtually identical kinetics and affinity as the single chain ValphaVbeta domain module (scD10) (Kd = 6-8 microm). The CD4 ectodomain does not alter either interaction. Moreover, CD4 alone demonstrates weak pMHCII binding (Kd = 200 microm), with no discernable affinity for the alphabeta TCR heterodimer. Hence, rather than providing a major contribution to binding energy, the critical role for the coreceptor in antigen-specific activation likely results from transient inducible recruitment of the CD4 cytoplasmic tail-associated lck tyrosine kinase to the pMHCII-ligated TCR complex.
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MESH Headings
- Antigen Presentation
- CD4 Antigens/genetics
- CD4 Antigens/metabolism
- Genes, MHC Class II
- Histocompatibility Antigens Class II
- Humans
- Kinetics
- Ligands
- Lymphocyte Activation
- Models, Immunological
- Peptide Fragments/genetics
- Peptide Fragments/metabolism
- Peptides/metabolism
- Protein Binding
- Receptors, Antigen, T-Cell/genetics
- Receptors, Antigen, T-Cell/metabolism
- Receptors, Antigen, T-Cell, alpha-beta/genetics
- Receptors, Antigen, T-Cell, alpha-beta/metabolism
- Recombinant Fusion Proteins/immunology
- Recombinant Fusion Proteins/metabolism
- Signal Transduction
- T-Lymphocytes, Helper-Inducer/immunology
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Affiliation(s)
- Y Xiong
- Laboratory of Immunobiology, Dana-Farber Cancer Institute and Department of Medicine, Harvard Medical School, Boston, Massachusetts 02115, USA
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36
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Sasada T, Reinherz EL. A critical role for CD2 in both thymic selection events and mature T cell function. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2001; 166:2394-403. [PMID: 11160298 DOI: 10.4049/jimmunol.166.4.2394] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
To examine the function of CD2 in vivo, N15 TCR transgenic (tg) RAG-2(-/-) H-2(b) mice bearing a single TCR specific for the vesicular stomatitis virus octapeptide bound to the H-2K(b) molecule were compared on a wild-type or CD2(-/-) background. In N15tg RAG-2(-/-) CD2(-/-) mice, thymic dysfunction is evident by 6 wk with a pre-TCR block in the CD4(-)CD8(-) double-negative thymocytes at the CD25(+)CD44(-) stage. Moreover, mature N15tg RAG-2(-/-) CD2(-/-) T cells are approximately 100-fold less responsive to vesicular stomatitis virus octapeptide and unresponsive to weak peptide agonists, as judged by IFN-gamma production. Repertoire analysis shows substantial differences in Valpha usage between non-tg C57BL/6 (B6) and B6 CD2(-/-) mice. Collectively, these findings show that CD2 plays a role in pre-TCR function in double-negative thymocytes, TCR selection events during thymocyte development, and TCR-stimulated cytokine production in mature T cells.
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MESH Headings
- Animals
- Antigens, Viral/immunology
- CD2 Antigens/biosynthesis
- CD2 Antigens/genetics
- CD2 Antigens/physiology
- Cell Differentiation/genetics
- Cell Differentiation/immunology
- Cytotoxicity, Immunologic/genetics
- Gene Rearrangement, alpha-Chain T-Cell Antigen Receptor
- Gene Rearrangement, beta-Chain T-Cell Antigen Receptor
- Immunophenotyping
- Interferon-gamma/antagonists & inhibitors
- Interferon-gamma/biosynthesis
- Interleukin-12/physiology
- Killer Cells, Natural/immunology
- Lymphocyte Activation/genetics
- Lymphocyte Count
- Lymphopenia/genetics
- Lymphopenia/immunology
- Lymphopenia/pathology
- Membrane Glycoproteins/deficiency
- Membrane Glycoproteins/genetics
- Membrane Glycoproteins/physiology
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Mice, Transgenic
- Receptors, Antigen, T-Cell, alpha-beta/deficiency
- Receptors, Antigen, T-Cell, alpha-beta/genetics
- Signal Transduction/genetics
- Signal Transduction/immunology
- Spleen/immunology
- Spleen/pathology
- T-Lymphocyte Subsets/cytology
- T-Lymphocyte Subsets/immunology
- T-Lymphocyte Subsets/metabolism
- T-Lymphocyte Subsets/pathology
- T-Lymphocytes, Cytotoxic/immunology
- Thymus Gland/cytology
- Thymus Gland/immunology
- Thymus Gland/metabolism
- Thymus Gland/pathology
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Affiliation(s)
- T Sasada
- Laboratory of Immunobiology, Dana-Farber Cancer Institute and Department of Medicine, Harvard Medical School, Boston, MA 02115, USA
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37
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Speir JA, Stevens J, Joly E, Butcher GW, Wilson IA. Two different, highly exposed, bulged structures for an unusually long peptide bound to rat MHC class I RT1-Aa. Immunity 2001; 14:81-92. [PMID: 11163232 DOI: 10.1016/s1074-7613(01)00091-7] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The rat MHC class Ia molecule RT1-Aa has the unusual capacity to bind long peptides ending in arginine, such as MTF-E, a thirteen-residue, maternally transmitted minor histocompatibility antigen. The antigenic structure of MTF-E was unpredictable due to its extraordinary length and two arginines that could serve as potential anchor residues. The crystal structure of RT1-Aa-MTF-E at 2.55 A shows that both peptide termini are anchored, as in other class I molecules, but the central residues in two independent pMHC complexes adopt completely different bulged conformations based on local environment. The MTF-E epitope is fully exposed within the putative T cell receptor (TCR) footprint. The flexibility demonstrated by the MTF-E structures illustrates how different TCRs may be raised against chemically identical, but structurally dissimilar, pMHC complexes.
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Affiliation(s)
- J A Speir
- Department of Molecular Biology and, Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
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38
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Abstract
During the past year, advances in our understanding of receptor-ligand interactions between opposing cell surfaces have occurred at a structural level. These include adhesion involving CD2-CD58, antigen-specific T-cell receptor interactions with peptides bound to major histocompatibility complex molecules (both pMHCI and pMHCII), the CD8alphaalpha co-receptor-pMHCI interaction and the binding of two distinct classes of natural killer receptors to self-MHC ligands.
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Affiliation(s)
- J Wang
- Dana-Farber Cancer Institute and Department of Pediatrics and Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA.
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39
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De Oliveira DB, Harfouch-Hammoud E, Otto H, Papandreou NA, Stern LJ, Cohen H, Boehm BO, Bach J, Caillat-Zucman S, Walk T, Jung G, Eliopoulos E, Papadopoulos GK, van Endert PM. Structural analysis of two HLA-DR-presented autoantigenic epitopes: crucial role of peripheral but not central peptide residues for T-cell receptor recognition. Mol Immunol 2000; 37:813-25. [PMID: 11257303 DOI: 10.1016/s0161-5890(00)00109-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Specific and major histocompatibility complex (MHC)-restricted T-cell recognition of antigenic peptides is based on interactions of the T-cell receptor (TCR) with the MHC alpha helices and solvent exposed peptide residues termed TCR contacts. In the case of MHC class II-presented peptides, the latter are located in the positions p2/3, p5 and p7/8 between MHC anchor residues. For numerous epitopes, peptide substitution studies have identified the central residue p5 as primary TCR contact characterized by very low permissiveness for peptide substitution, while the more peripheral positions generally represent auxiliary TCR contacts. In structural studies of TCR/peptide/MHC complexes, this has been shown to be due to intimate contact between the TCR complementarity determining region (CDR) three loops and the central peptide residue. We asked whether this model also applied to two HLA-DR presented epitopes derived from an antigen targeted in type 1 diabetes. Large panels of epitope variants with mainly conservative single substitutions were tested for human leukocyte antigen (HLA) class II binding affinity and T cell stimulation. Both epitopes bind with high affinity to the presenting HLA-DR molecules. However, in striking contrast to the standard distribution of TCR contacts, recognition of the central p5 residue displayed high permissiveness even for non-conservative substitutions, while the more peripheral p2 and p8 TCR contacts showed very low permissiveness for substitution. This suggests that intimate TCR interaction with the central peptide residue is not always required for specific antigen recognition and can be compensated by interactions with positions normally acting as auxiliary contacts.
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Affiliation(s)
- D B De Oliveira
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA
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Schueler-Furman O, Altuvia Y, Sette A, Margalit H. Structure-based prediction of binding peptides to MHC class I molecules: application to a broad range of MHC alleles. Protein Sci 2000; 9:1838-46. [PMID: 11045629 PMCID: PMC2144704 DOI: 10.1110/ps.9.9.1838] [Citation(s) in RCA: 121] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Specific binding of antigenic peptides to major histocompatibility complex (MHC) class I molecules is a prerequisite for their recognition by cytotoxic T-cells. Prediction of MHC-binding peptides must therefore be incorporated in any predictive algorithm attempting to identify immunodominant T-cell epitopes, based on the amino acid sequence of the protein antigen. Development of predictive algorithms based on experimental binding data requires experimental testing of a very large number of peptides. A complementary approach relies on the structural conservation observed in crystallographically solved peptide-MHC complexes. By this approach, the peptide structure in the MHC groove is used as a template upon which peptide candidates are threaded, and their compatibility to bind is evaluated by statistical pairwise potentials. Our original algorithm based on this approach used the pairwise potential table of Miyazawa and Jernigan (Miyazawa S, Jernigan RL, 1996, J Mol Biol 256:623-644) and succeeded to correctly identify good binders only for MHC molecules with hydrophobic binding pockets, probably because of the high emphasis of hydrophobic interactions in this table. A recently developed pairwise potential table by Betancourt and Thirumalai (Betancourt MR, Thirumalai D, 1999, Protein Sci 8:361-369) that is based on the Miyazawa and Jernigan table describes the hydrophilic interactions more appropriately. In this paper, we demonstrate how the use of this table, together with a new definition of MHC contact residues by which only residues that contribute exclusively to sequence specific binding are included, allows the development of an improved algorithm that can be applied to a wide range of MHC class I alleles.
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Affiliation(s)
- O Schueler-Furman
- Department of Molecular Genetics and Biotechnology, The Hebrew University, Hadassah Medical School, Jerusalem, Israel
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Kalergis AM, Nathenson SG. Altered peptide ligand-mediated TCR antagonism can be modulated by a change in a single amino acid residue within the CDR3 beta of an MHC class I-restricted TCR. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2000; 165:280-5. [PMID: 10861062 DOI: 10.4049/jimmunol.165.1.280] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The Ag receptor of cytotoxic CD8+ T lymphocytes recognizes peptides of 8-10 aa bound to MHC class I molecules. This Ag recognition event leads to the activation of the CD8+ lymphocyte and subsequent lysis of the target cell. Altered peptide ligands are analogues derived from the original antigenic peptide that commonly carry amino acid substitutions at TCR contact residues. TCR engagement by these altered peptide ligands usually impairs normal T cell function. Some of these altered peptide ligands (antagonists) are able to specifically antagonize and inhibit T cell activation induced by the wild-type antigenic peptide. Despite significant advances made in understanding TCR antagonism, the molecular interactions between the TCR and the MHC/peptide complex responsible for the inhibitory activity of antagonist peptides remain elusive. To approach this question, we have identified altered peptide ligands derived from the vesicular stomatitis virus peptide (RGYVYQGL) that specifically antagonize an H-2Kb/vesicular stomatitis virus-specific TCR. Furthermore, by site-directed mutagenesis, we altered single amino acid residues of the complementarity-determining region 3 of the beta-chain of this TCR and tested the effect of these point mutations on Ag recognition and TCR antagonism. Here we show that a single amino acid change on the TCR CDR3 beta loop can modulate the TCR-antagonistic properties of an altered peptide ligand. Our results highlight the role of the TCR complementarity-determining region 3 loops for controlling the nature of the T cell response to TCR/altered peptide ligand interactions, including those leading to TCR antagonism.
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MESH Headings
- Amino Acid Sequence
- Amino Acid Substitution/immunology
- Animals
- Antigen Presentation/genetics
- Antigens, Viral/genetics
- Antigens, Viral/immunology
- Antigens, Viral/metabolism
- Arginine/genetics
- Binding, Competitive/genetics
- Binding, Competitive/immunology
- Glutamic Acid/genetics
- Glutamine/genetics
- H-2 Antigens/immunology
- H-2 Antigens/metabolism
- Ligands
- Mice
- Molecular Sequence Data
- Mutagenesis, Site-Directed
- Peptides/chemical synthesis
- Peptides/genetics
- Peptides/immunology
- Peptides/metabolism
- Point Mutation
- Protein Binding/genetics
- Protein Binding/immunology
- Receptors, Antigen, T-Cell, alpha-beta/antagonists & inhibitors
- Receptors, Antigen, T-Cell, alpha-beta/metabolism
- Vesicular stomatitis Indiana virus/genetics
- Vesicular stomatitis Indiana virus/immunology
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Affiliation(s)
- A M Kalergis
- Departments of Microbiology and Immunology and Cell Biology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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Degano M, Garcia KC, Apostolopoulos V, Rudolph MG, Teyton L, Wilson IA. A functional hot spot for antigen recognition in a superagonist TCR/MHC complex. Immunity 2000; 12:251-61. [PMID: 10755612 DOI: 10.1016/s1074-7613(00)80178-8] [Citation(s) in RCA: 185] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
A longstanding question in T cell receptor signaling is how structurally similar ligands, with similar affinities, can have substantially different biological activity. The crystal structure of the 2C TCR complex of H-2Kb with superagonist peptide SIYR at 2.8 A elucidates a structural basis for TCR discrimination of altered peptide ligands. The difference in antigen potency is modulated by two cavities in the TCR combining site, formed mainly by CDRs 3alpha, 3beta, and 1beta, that complement centrally located peptide residues. This "functional hot spot" allows the TCR to finely discriminate amongst energetically similar interactions within different ligands for those in which the peptide appropriately stabilizes the TCR/pMHC complex and provides a new structural perspective for understanding differential signaling resulting from T cell cross-reactivity.
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Affiliation(s)
- M Degano
- Department of Molecular Biology and Skaggs Institute for Chemical Biology, La Jolla, California 92037, USA
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43
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Reconstitution of T-cell receptor repertoire diversity following T-cell depleted allogeneic bone marrow transplantation is related to hematopoietic chimerism. Blood 2000. [DOI: 10.1182/blood.v95.1.352.001k43_352_359] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
CDR3 spectratyping was used to analyze the complexity of the T-cell repertoire and to define the mechanisms and kinetics of the reconstitution of T-cell immunity after allogeneic bone marrow transplantation (BMT). This method, which is based on polymerase chain reaction amplification of all CDR3 regions using the T-cell receptor (TCR) Vβ genes, was used to examine serial samples of peripheral blood lymphocytes from 11 adult patients with chronic myelogenous leukemia (CML) who underwent T-cell–depleted allogeneic BMT. In contrast to 10 normal donors who display highly diverse and polyclonal spectratypes, patient samples before and early after BMT revealed markedly skewed repertoires, consisting of absent, monoclonal, or oligoclonal profiles for the majority of Vβ subfamilies. To quantify changes in TCR repertoire over time, we established an 8-point scoring system for each Vβ subfamily. The mean complexity score for patient samples before transplant (130.8) was significantly lower than that for normal donors (183; P = 0.0007). TCR repertoire complexity was abnormal in all patients at 3 months after BMT (mean score = 87). Normalization of repertoire began in 4 patients at 6 months after BMT, but the majority of patients continued to display abnormal repertoires for up to 3 years after BMT. To determine whether the reconstituted T-cell repertoire was derived from the donor or recipient, unique microsatellite loci were examined to establish chimeric status. At 3 months after BMT, 7 patients demonstrated mixed chimerism; 4 had complete donor hematopoiesis (CDH). CDH strongly correlated with likelihood of restoration of T-cell repertoire complexity (P = 0.003). In contrast, patients who demonstrated persistence of recipient hematopoiesis failed to reconstitute a diverse TCR repertoire. These findings suggest that the reconstitution of a normal T-cell repertoire from T-cell progenitors in adults is influenced by interactions between recipient and donor hematopoietic cells. (Blood. 2000;95: 352-359)
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Reconstitution of T-cell receptor repertoire diversity following T-cell depleted allogeneic bone marrow transplantation is related to hematopoietic chimerism. Blood 2000. [DOI: 10.1182/blood.v95.1.352] [Citation(s) in RCA: 115] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Abstract
CDR3 spectratyping was used to analyze the complexity of the T-cell repertoire and to define the mechanisms and kinetics of the reconstitution of T-cell immunity after allogeneic bone marrow transplantation (BMT). This method, which is based on polymerase chain reaction amplification of all CDR3 regions using the T-cell receptor (TCR) Vβ genes, was used to examine serial samples of peripheral blood lymphocytes from 11 adult patients with chronic myelogenous leukemia (CML) who underwent T-cell–depleted allogeneic BMT. In contrast to 10 normal donors who display highly diverse and polyclonal spectratypes, patient samples before and early after BMT revealed markedly skewed repertoires, consisting of absent, monoclonal, or oligoclonal profiles for the majority of Vβ subfamilies. To quantify changes in TCR repertoire over time, we established an 8-point scoring system for each Vβ subfamily. The mean complexity score for patient samples before transplant (130.8) was significantly lower than that for normal donors (183; P = 0.0007). TCR repertoire complexity was abnormal in all patients at 3 months after BMT (mean score = 87). Normalization of repertoire began in 4 patients at 6 months after BMT, but the majority of patients continued to display abnormal repertoires for up to 3 years after BMT. To determine whether the reconstituted T-cell repertoire was derived from the donor or recipient, unique microsatellite loci were examined to establish chimeric status. At 3 months after BMT, 7 patients demonstrated mixed chimerism; 4 had complete donor hematopoiesis (CDH). CDH strongly correlated with likelihood of restoration of T-cell repertoire complexity (P = 0.003). In contrast, patients who demonstrated persistence of recipient hematopoiesis failed to reconstitute a diverse TCR repertoire. These findings suggest that the reconstitution of a normal T-cell repertoire from T-cell progenitors in adults is influenced by interactions between recipient and donor hematopoietic cells. (Blood. 2000;95: 352-359)
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Abstract
During the past year, a plethora of structural information has provided detailed insights into the interactions between classical MHC class I molecules and their cognate receptors on T cells. Likewise, there have been major advances in our knowledge of the structures and functions of five nonclassical MHC-like molecules: HLA-DM (murine H2-M), HLA-E, HFE, ZAG and MIC-A.
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Affiliation(s)
- K Maenaka
- Structural Biology, Wellcome Trust Centre for Human Genetics, Headington, OX3 7BN, UK.
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Kalergis AM, Ono T, Wang F, DiLorenzo TP, Honda S, Nathenson SG. Single Amino Acid Replacements in an Antigenic Peptide Are Sufficient to Alter the TCR Vβ Repertoire of the Responding CD8+ Cytotoxic Lymphocyte Population. THE JOURNAL OF IMMUNOLOGY 1999. [DOI: 10.4049/jimmunol.162.12.7263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Abstract
Cytotoxic CD8+ T lymphocytes are activated upon the engagement of their Ag-specific receptors by MHC class I molecules loaded with peptides 8–11 amino acids long. T cell responses triggered by certain antigenic peptides are restricted to a limited number of TCR Vβ elements. The precise role of the peptide in causing this restricted TCR Vβ expansion in vivo remains unclear. To address this issue, we immunized C57BL/6 mice with the immunodominant peptide of the vesicular stomatitis virus (VSV) and several peptide variants carrying single substitutions at TCR-contact residues. We observed the expansion of a limited set of TCR Vβ elements responding to each peptide variant. To focus our analysis solely on the TCR β-chain, we created a transgenic mouse expressing exclusively the TCR α-chain from a VSV peptide-specific CD8+ T cell clone. These mice showed an even more restricted TCR Vβ usage consequent to peptide immunization. However, in both C57BL/6 and TCRα transgenic mice, single amino acid replacements in TCR-contact residues of the VSV peptide could alter the TCR Vβ usage of the responding CD8+ T lymphocytes. These results provide in vivo evidence for an interaction between the antigenic peptide and the germline-encoded complementarity-determining region-β loops that can influence the selection of the responding TCR repertoire. Furthermore, only replacements at residues near the C terminus of the peptide were able to alter the TCR Vβ usage, which is consistent with the notion that the TCR β-chain interacts in vivo preferentially with this region of the MHC/peptide complex.
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Affiliation(s)
| | | | - Fuming Wang
- †Cell Biology, Albert Einstein College of Medicine, Bronx, NY 10461
| | | | | | - Stanley G. Nathenson
- *Microbiology and Immunology and
- †Cell Biology, Albert Einstein College of Medicine, Bronx, NY 10461
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