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Collins EJ, Riddle DS. TCR-MHC docking orientation: natural selection, or thymic selection? Immunol Res 2009; 41:267-94. [PMID: 18726714 DOI: 10.1007/s12026-008-8040-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
T cell receptors (TCR) dock on their peptide-major histocompatibility complex (pMHC) targets in a conserved orientation. Since amino acid sidechains are the foundation of specific protein-protein interactions, a simple explanation for the conserved docking orientation is that key amino acids encoded by the TCR and MHC genes have been selected and maintained through evolution in order to preserve TCR/pMHC binding. Expectations that follow from the hypothesis that TCR and MHC evolved to interact are discussed in light of the data that both support and refute them. Finally, an alternative and equally simple explanation for the driving force behind the conserved docking orientation is described.
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Affiliation(s)
- Edward J Collins
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, 804 Mary Ellen Jones Building, Chapel Hill, NC 27510, USA.
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202
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Münz C, Lünemann JD, Getts MT, Miller SD. Antiviral immune responses: triggers of or triggered by autoimmunity? Nat Rev Immunol 2009; 9:246-58. [PMID: 19319143 PMCID: PMC2854652 DOI: 10.1038/nri2527] [Citation(s) in RCA: 341] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The predisposition of individuals to several common autoimmune diseases, such as rheumatoid arthritis, systemic lupus erythematosus and multiple sclerosis, is genetically linked to certain human MHC class II molecules and other immune modulators. However, genetic predisposition is only one risk factor for the development of these diseases, and low concordance rates in monozygotic twins, as well as the geographical distribution of disease risk, suggest the involvement of environmental factors in the development of these diseases. Among these environmental factors, infections have been implicated in the onset and/or promotion of autoimmunity. In this Review, we outline the mechanisms by which viral infection can trigger autoimmune disease and describe the pathways by which infection and immune control of infectious disease might be dysregulated during autoimmunity.
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Affiliation(s)
- Christian Münz
- Viral Immunobiology, Institute of Experimental Immunology, University Hospital Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland.
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203
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Ziegler A, Müller CA, Böckmann RA, Uchanska-Ziegler B. Low-affinity peptides and T-cell selection. Trends Immunol 2009; 30:53-60. [PMID: 19201651 DOI: 10.1016/j.it.2008.11.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2008] [Revised: 10/15/2008] [Accepted: 11/10/2008] [Indexed: 01/17/2023]
Abstract
The dual requirement for T cells to recognize a particular major histocompatibility complex (MHC) antigen presenting a foreign peptide and to lack strong reactivity with a complex of the same molecule when bound to a self-peptide, is attained by thymic positive and negative selection processes, the molecular details of which are currently only partially understood. However, the discovery of the thymoproteasome and our improved understanding of the dynamics of peptide presentation permit us to suggest that the biophysical properties of the MHC:peptide class I complexes engaged in positive T-cell selection will be distinct from those involved in negative selection, hence imposing differential barriers for T cells.
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Affiliation(s)
- Andreas Ziegler
- Institut für Immungenetik, Charité-Universitätsmedizin Berlin, Campus Benjamin Franklin, Freie Universität Berlin, Thielallee 73, 14195 Berlin, Germany.
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204
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Garcia KC, Adams JJ, Feng D, Ely LK. The molecular basis of TCR germline bias for MHC is surprisingly simple. Nat Immunol 2009; 10:143-7. [PMID: 19148199 PMCID: PMC3982143 DOI: 10.1038/ni.f.219] [Citation(s) in RCA: 186] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The elusive etiology of germline bias of the T cell receptor (TCR) for major histocompatibility complex (MHC) has been clarified by recent 'proof-of-concept' structural results demonstrating the conservation of specific TCR-MHC interfacial contacts in complexes bearing common variable segments and MHC allotypes. We suggest that each TCR variable-region gene product engages each type of MHC through a 'menu' of structurally coded recognition motifs that have arisen through coevolution. The requirement for MHC-restricted T cell recognition during thymic selection and peripheral surveillance has necessitated the existence of such a coded recognition system. Given these findings, a reconsideration of the TCR-peptide-MHC structural database shows that not only have the answers been there all along but also they were predictable by the first principles of physical chemistry.
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Affiliation(s)
- K Christopher Garcia
- Department of Molecular & Cellular Physiology, Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, California 94305, USA.
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205
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Jones LL, Colf LA, Stone JD, Garcia KC, Kranz DM. Distinct CDR3 conformations in TCRs determine the level of cross-reactivity for diverse antigens, but not the docking orientation. THE JOURNAL OF IMMUNOLOGY 2009; 181:6255-64. [PMID: 18941216 DOI: 10.4049/jimmunol.181.9.6255] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
T cells are known to cross-react with diverse peptide MHC Ags through their alphabeta TCR. To explore the basis of such cross-reactivity, we examined the 2C TCR that recognizes two structurally distinct ligands, SIY-K(b) and alloantigen QL9-L(d). In this study we characterized the cross-reactivity of several high-affinity 2C TCR variants that contained mutations only in the CDR3alpha loop. Two of the TCR lost their ability to cross-react with the reciprocal ligand (SIY-K(b)), whereas another TCR (m67) maintained reactivity with both ligands. Crystal structures of four of the TCRs in complex with QL9-L(d) showed that CDR1, CDR2, and CDR3beta conformations and docking orientations were remarkably similar. Although the CDR3alpha loop of TCR m67 conferred a 2000-fold higher affinity for SIY-K(b), the TCR maintained the same docking angle on QL9-L(d) as the 2C TCR. Thus, CDR3alpha dictated the affinity and level of cross-reactivity, yet it did so without affecting the conserved docking orientation.
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Affiliation(s)
- Lindsay L Jones
- Department of Biochemistry, University of Illinois, Urbana, IL 61801, USA
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206
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Archbold JK, Macdonald WA, Gras S, Ely LK, Miles JJ, Bell MJ, Brennan RM, Beddoe T, Wilce MCJ, Clements CS, Purcell AW, McCluskey J, Burrows SR, Rossjohn J. Natural micropolymorphism in human leukocyte antigens provides a basis for genetic control of antigen recognition. ACTA ACUST UNITED AC 2009; 206:209-19. [PMID: 19139173 PMCID: PMC2626662 DOI: 10.1084/jem.20082136] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Human leukocyte antigen (HLA) gene polymorphism plays a critical role in protective immunity, disease susceptibility, autoimmunity, and drug hypersensitivity, yet the basis of how HLA polymorphism influences T cell receptor (TCR) recognition is unclear. We examined how a natural micropolymorphism in HLA-B44, an important and large HLA allelic family, affected antigen recognition. T cell–mediated immunity to an Epstein-Barr virus determinant (EENLLDFVRF) is enhanced when HLA-B*4405 was the presenting allotype compared with HLA-B*4402 or HLA-B*4403, each of which differ by just one amino acid. The micropolymorphism in these HLA-B44 allotypes altered the mode of binding and dynamics of the bound viral epitope. The structure of the TCR–HLA-B*4405EENLLDFVRF complex revealed that peptide flexibility was a critical parameter in enabling preferential engagement with HLA-B*4405 in comparison to HLA-B*4402/03. Accordingly, major histocompatibility complex (MHC) polymorphism can alter the dynamics of the peptide-MHC landscape, resulting in fine-tuning of T cell responses between closely related allotypes.
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Affiliation(s)
- Julia K Archbold
- The Protein Crystallography Unit, Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Monash University, Clayton, Victoria 3800, Australia
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207
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Cohn M. Why rethink the structure-function relationships regulating TCR behavior? CURRENT TRENDS IN IMMUNOLOGY 2009; 10:105-111. [PMID: 22573930 PMCID: PMC3345953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Although the generally accepted (Standard) Model of the TCR has powered the accumulation of a large body of crucial data, it is lacking because of the failure of its basic tenet that allele-specific recognition of MHC-encoded restricting elements can be derived by somatic selection on a random repertoire. The limitations of the Standard Model due to this tenet and a glimpse at what a competing model might look like add up to yield a surprising new view of the structure-function relationships of the TCR. A published experiment illustrating this is discussed.
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Affiliation(s)
- Melvin Cohn
- Conceptual Immunology Group, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, Tel: (858) 453-4100 Ext. 1351
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208
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Mareeva T, Martinez-Hackert E, Sykulev Y. How a T cell receptor-like antibody recognizes major histocompatibility complex-bound peptide. J Biol Chem 2008; 283:29053-9. [PMID: 18703505 PMCID: PMC2570882 DOI: 10.1074/jbc.m804996200] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2008] [Revised: 07/30/2008] [Indexed: 11/06/2022] Open
Abstract
We determined the crystal structures of the T cell receptor (TCR)-like antibody 25-D1.16 Fab fragment bound to a complex of SIINFEKL peptide from ovalbumin and the H-2K(b) molecule. Remarkably, this antibody directly "reads" the structure of the major histocompatibility complex (MHC)-bound peptide, employing the canonical diagonal binding mode utilized by most TCRs. This is in marked contrast with another TCR-like antibody, Hyb3, bound to melanoma peptide MAGE-A1 in association with HLA-A1 MHC class I. Hyb3 assumes a non-canonical orientation over its cognate peptide-MHC and appears to recognize a conformational epitope in which the MHC contribution is dominant. We conclude that TCR-like antibodies can recognize MHC-bound peptide via two different mechanisms: one is similar to that exploited by the preponderance of TCRs and the other requires a non-canonical antibody orientation over the peptide-MHC complex.
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Affiliation(s)
- Tatiana Mareeva
- Department of Microbiology and Immunology and the Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA
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209
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Marrack P, Rubtsova K, Scott-Browne J, Kappler JW. T cell receptor specificity for major histocompatibility complex proteins. Curr Opin Immunol 2008; 20:203-7. [PMID: 18456484 DOI: 10.1016/j.coi.2008.03.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2007] [Accepted: 03/11/2008] [Indexed: 10/22/2022]
Abstract
The ligands for alpha beta T cell receptors (alphabetaTCRs) are usually major histocompatibility complex (MHC) proteins bound to peptides. Although there is evidence that T cell receptor variable regions have been selected evolutionarily to bind MHC, the rules governing this interaction have not previously been apparent. However, recent solved structures of T cell receptors with related variable regions bound to MHC plus peptides suggest that some amino acids in variable region CDR1 and CDR2s almost always react in a consistent way with MHC. These amino acids may therefore have been selected evolutionarily to predispose T cell receptors toward recognition of MHC ligands.
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Affiliation(s)
- Philippa Marrack
- Howard Hughes Medical Institute, National Jewish Medical and Research Center, Denver, Colorado 80206, USA.
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210
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Dai S, Huseby ES, Rubtsova K, Scott-Browne J, Crawford F, Macdonald WA, Kappler JW, Marrack P. Crossreactive T Cells spotlight the germline rules for alphabeta T cell-receptor interactions with MHC molecules. Immunity 2008; 28:324-34. [PMID: 18308592 PMCID: PMC2287197 DOI: 10.1016/j.immuni.2008.01.008] [Citation(s) in RCA: 140] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2008] [Accepted: 01/15/2008] [Indexed: 01/11/2023]
Abstract
To test whether highly crossreactive alphabeta T cell receptors (TCRs) produced during limited negative selection best illustrate evolutionarily conserved interactions between TCR and major histocompatibility complex (MHC) molecules, we solved the structures of three TCRs bound to the same MHC II peptide (IAb-3K). The TCRs had similar affinities for IAb-3K but varied from noncrossreactive to extremely crossreactive with other peptides and MHCs. Crossreactivity correlated with a shrinking, increasingly hydrophobic TCR-ligand interface, involving fewer TCR amino acids. A few CDR1 and CDR2 amino acids dominated the most crossreactive TCR interface with MHC, including Vbeta8 48Y and 54E and Valpha4 29Y, arranged to impose the familiar diagonal orientation of TCR on MHC. These interactions contribute to MHC binding by other TCRs using related V regions, but not usually so dominantly. These data show that crossreactive TCRs can spotlight the evolutionarily conserved features of TCR-MHC interactions and that these interactions impose the diagonal docking of TCRs on MHC.
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Affiliation(s)
- Shaodong Dai
- Howard Hughes Medical Institute, National Jewish Medical and Research Center, Denver, CO 80206 USA
- Integrated Department of Immunology, National Jewish Medical and Research Center, Denver, CO 80206 USA
| | - Eric S. Huseby
- Howard Hughes Medical Institute, National Jewish Medical and Research Center, Denver, CO 80206 USA
- Integrated Department of Immunology, National Jewish Medical and Research Center, Denver, CO 80206 USA
| | - Kira Rubtsova
- Integrated Department of Immunology, National Jewish Medical and Research Center, Denver, CO 80206 USA
| | - James Scott-Browne
- Integrated Department of Immunology, National Jewish Medical and Research Center, Denver, CO 80206 USA
| | - Frances Crawford
- Howard Hughes Medical Institute, National Jewish Medical and Research Center, Denver, CO 80206 USA
- Integrated Department of Immunology, National Jewish Medical and Research Center, Denver, CO 80206 USA
| | | | - John W. Kappler
- Howard Hughes Medical Institute, National Jewish Medical and Research Center, Denver, CO 80206 USA
- Integrated Department of Immunology, National Jewish Medical and Research Center, Denver, CO 80206 USA
- Program in Biomolecular Structure, University of Colorado at Denver and Health Sciences Center, Aurora, CO 80045 USA
| | - Philippa Marrack
- Howard Hughes Medical Institute, National Jewish Medical and Research Center, Denver, CO 80206 USA
- Integrated Department of Immunology, National Jewish Medical and Research Center, Denver, CO 80206 USA
- Department of Biochemistry and Molecular Genetics, University of Colorado at Denver and Health Sciences Center, Aurora, CO 80045
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