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Ballabio F, Broggini L, Paissoni C, Han X, Peqini K, Sala BM, Sun R, Sandalova T, Barbiroli A, Achour A, Pellegrino S, Ricagno S, Camilloni C. l- to d-Amino Acid Substitution in the Immunodominant LCMV-Derived Epitope gp33 Highlights the Sensitivity of the TCR Recognition Mechanism for the MHC/Peptide Structure and Dynamics. ACS OMEGA 2022; 7:9622-9635. [PMID: 35350306 PMCID: PMC8945122 DOI: 10.1021/acsomega.1c06964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Accepted: 02/04/2022] [Indexed: 06/14/2023]
Abstract
Presentation of pathogen-derived epitopes by major histocompatibility complex I (MHC-I) can lead to the activation and expansion of specific CD8+ T cell clones, eventually resulting in the destruction of infected target cells. Altered peptide ligands (APLs), designed to elicit immunogenicity toward a wild-type peptide, may affect the overall stability of MHC-I/peptide (pMHC) complexes and modulate the recognition by T cell receptors (TCR). Previous works have demonstrated that proline substitution at position 3 (p3P) of different MHC-restricted epitopes, including the immunodominant LCMV-derived epitope gp33 and escape variants, may be an effective design strategy to increase epitope immunogenicity. These studies hypothesized that the p3P substitution increases peptide rigidity, facilitating TCR binding. Here, molecular dynamics simulations indicate that the p3P modification rigidifies the APLs in solution predisposing them for the MHC-I loading as well as once bound to H-2Db, predisposing them for TCR binding. Our results also indicate that peptide position 6, key for interaction of H-2Db/gp33 with the TCR P14, takes a suboptimal conformation before as well as after binding to the TCR. Analyses of H-2Db in complex with APLs, in which position 6 was subjected to an l- to d-amino acid modification, revealed small conformational changes and comparable pMHC thermal stability. However, the l- to d-modification reduced significantly the binding to P14 even in the presence of the p3P modification. Our combined data highlight the sensitivity of the TCR for the conformational dynamics of pMHC and provide further tools to dissect and modulate TCR binding and immunogenicity via APLs.
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Affiliation(s)
- Federico Ballabio
- Dipartimento
di Bioscienze, Università degli Studi
di Milano, Milano 20133, Italy
| | - Luca Broggini
- Dipartimento
di Bioscienze, Università degli Studi
di Milano, Milano 20133, Italy
- Institute
of Molecular and Translational Cardiology, IRCCS Policlinico San Donato, San Donato Milanese 20097, Italy
| | - Cristina Paissoni
- Dipartimento
di Bioscienze, Università degli Studi
di Milano, Milano 20133, Italy
| | - Xiao Han
- Science
for Life Laboratory, Department of Medicine, Karolinska Institute,
& Division of Infectious Diseases, Karolinska
University Hospital, Stockholm 14186, Sweden
| | - Kaliroi Peqini
- DISFARM,
Dipartimento di Scienze Farmaceutiche, Sezione Chimica Generale e
Organica, Università degli Studi
di Milano, Milano 20122, Italy
| | - Benedetta Maria Sala
- Science
for Life Laboratory, Department of Medicine, Karolinska Institute,
& Division of Infectious Diseases, Karolinska
University Hospital, Stockholm 14186, Sweden
| | - Renhua Sun
- Science
for Life Laboratory, Department of Medicine, Karolinska Institute,
& Division of Infectious Diseases, Karolinska
University Hospital, Stockholm 14186, Sweden
| | - Tatyana Sandalova
- Science
for Life Laboratory, Department of Medicine, Karolinska Institute,
& Division of Infectious Diseases, Karolinska
University Hospital, Stockholm 14186, Sweden
| | - Alberto Barbiroli
- Dipartimento
di Scienze per gli Alimenti, la Nutrizione e l’Ambiente, Università degli Studi di Milano, Milano 20122, Italy
| | - Adnane Achour
- Science
for Life Laboratory, Department of Medicine, Karolinska Institute,
& Division of Infectious Diseases, Karolinska
University Hospital, Stockholm 14186, Sweden
| | - Sara Pellegrino
- DISFARM,
Dipartimento di Scienze Farmaceutiche, Sezione Chimica Generale e
Organica, Università degli Studi
di Milano, Milano 20122, Italy
| | - Stefano Ricagno
- Dipartimento
di Bioscienze, Università degli Studi
di Milano, Milano 20133, Italy
- Institute
of Molecular and Translational Cardiology, IRCCS Policlinico San Donato, San Donato Milanese 20097, Italy
| | - Carlo Camilloni
- Dipartimento
di Bioscienze, Università degli Studi
di Milano, Milano 20133, Italy
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2
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Combining Well-Tempered Metadynamics Simulation and SPR Assays to Characterize the Binding Mechanism of the Universal T-Lymphocyte Tetanus Toxin Epitope TT830-843. BIOMED RESEARCH INTERNATIONAL 2021; 2021:5568980. [PMID: 34285916 PMCID: PMC8275407 DOI: 10.1155/2021/5568980] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 05/27/2021] [Accepted: 06/06/2021] [Indexed: 11/17/2022]
Abstract
Peptide TT830-843 from the tetanus toxin is a universal T-cell epitope. It helps in vaccination and induces T-cell activation. However, the fine molecular interaction between this antigen and the major histocompatibility complex (MHC) remains unknown. Molecular analysis of its interaction with murine MHC (H-2) was proposed to explore its immune response efficiency. Molecular dynamics simulations are important mechanisms for understanding the basis of protein-ligand interactions, and metadynamics is a useful technique for enhancing sampling in molecular dynamics. SPR (surface plasmon resonance) assays were used to validate whether the metadynamics results are in accordance with the experimental results. The peptide TT830-843 unbinding process was simulated, and the free energy surface reconstruction revealed a detailed conformational landscape. The simulation described the exiting path as a stepwise mechanism between progressive detachment states. We pointed out how the terminus regions act as anchors for binding and how the detachment mechanism includes the opening of α-helices to permit the peptide's central region dissociation. The results indicated the peptide/H-2 receptor encounter occurs within a distance lesser than 27.5 Å, and the encounter can evolve to form a stable complex. SPR assays confirmed the complex peptide/H-2 as a thermodynamically stable system, exhibiting enough free energy to interact with TCR on the antigen-presenting cell surface. Therefore, combining in silico and in vitro assays provided significant evidence to support the peptide/H-2 complex formation.
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3
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Josephs TM, Grant EJ, Gras S. Molecular challenges imposed by MHC-I restricted long epitopes on T cell immunity. Biol Chem 2017; 398:1027-1036. [PMID: 28141543 DOI: 10.1515/hsz-2016-0305] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Accepted: 01/25/2017] [Indexed: 11/15/2022]
Abstract
It has widely been accepted that major histocompatibility complex class I molecules (MHC-I) are limited to binding small peptides of 8-10 residues in length. However, this consensus has recently been challenged with the identification of longer peptides (≥11 residues) that can also elicit cytotoxic CD8+ T cell responses. Indeed, a growing number of studies demonstrate that these non-canonical epitopes are important targets for the immune system. As long epitopes represent up to 10% of the peptide repertoire bound to MHC-I molecules, here we review their impact on antigen presentation by MHC-I, TCR recognition, and T cell immunity.
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DockTope: a Web-based tool for automated pMHC-I modelling. Sci Rep 2015; 5:18413. [PMID: 26674250 PMCID: PMC4682062 DOI: 10.1038/srep18413] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2015] [Accepted: 11/18/2015] [Indexed: 11/08/2022] Open
Abstract
The immune system is constantly challenged, being required to protect the organism against a wide variety of infectious pathogens and, at the same time, to avoid autoimmune disorders. One of the most important molecules involved in these events is the Major Histocompatibility Complex class I (MHC-I), responsible for binding and presenting small peptides from the intracellular environment to CD8+ T cells. The study of peptide:MHC-I (pMHC-I) molecules at a structural level is crucial to understand the molecular mechanisms underlying immunologic responses. Unfortunately, there are few pMHC-I structures in the Protein Data Bank (PDB) (especially considering the total number of complexes that could be formed combining different peptides), and pMHC-I modelling tools are scarce. Here, we present DockTope, a free and reliable web-based tool for pMHC-I modelling, based on crystal structures from the PDB. DockTope is fully automated and allows any researcher to construct a pMHC-I complex in an efficient way. We have reproduced a dataset of 135 non-redundant pMHC-I structures from the PDB (Cα RMSD below 1 Å). Modelling of pMHC-I complexes is remarkably important, contributing to the knowledge of important events such as cross-reactivity, autoimmunity, cancer therapy, transplantation and rational vaccine design.
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Two distinct conformations of a rinderpest virus epitope presented by bovine major histocompatibility complex class I N*01801: a host strategy to present featured peptides. J Virol 2011; 85:6038-48. [PMID: 21450819 DOI: 10.1128/jvi.00030-11] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The presentation of viral peptide epitopes to host cytotoxic T lymphocytes (CTLs) is crucial for adaptive cellular immunity to clear the virus infection, especially for some chronic viral infections. Indeed, hosts have developed effective strategies to achieve this goal. The ideal scenario would be that the peptide epitopes stimulate a broad spectrum of CTL responses with diversified T-cell receptor (TCR) usage (the TCR repertoire). It is believed that a diversified TCR repertoire requires a "featured" peptide to be presented by the host major histocompatibility complex (MHC). A featured peptide can be processed and presented in a number of ways. Here, using the X-ray diffraction method, the crystal structures of an antigenic peptide derived from rinderpest virus presented by bovine MHC class I N*01801 (BoLA-A11) have been solved, and two distinct conformations of the presented peptide are clearly displayed. A detailed analysis of the structure and comparative sequences revealed that the polymorphic amino acid isoleucine 73 (Ile73) is extremely flexible, allowing the MHC groove to adopt different conformations to accommodate the rinderpest virus peptide. This makes the peptide more featured by exposing different amino acids for T-cell recognition. The crystal structures also demonstrated that the N*01801 molecule has an unusually large A pocket, resulting in the special conformation of the P1 residue at the N terminus of the peptide. We propose that this strategy of host peptide presentation might be beneficial for creating a diversified TCR repertoire, which is important for a more-effective CTL response.
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Macdonald IK, Harkiolaki M, Hunt L, Connelley T, Carroll AV, MacHugh ND, Graham SP, Jones EY, Morrison WI, Flower DR, Ellis SA. MHC class I bound to an immunodominant Theileria parva epitope demonstrates unconventional presentation to T cell receptors. PLoS Pathog 2010; 6:e1001149. [PMID: 20976198 PMCID: PMC2954893 DOI: 10.1371/journal.ppat.1001149] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2010] [Accepted: 09/10/2010] [Indexed: 01/07/2023] Open
Abstract
T cell receptor (TCR) recognition of peptide-MHC class I (pMHC) complexes is a crucial event in the adaptive immune response to pathogens. Peptide epitopes often display a strong dominance hierarchy, resulting in focusing of the response on a limited number of the most dominant epitopes. Such T cell responses may be additionally restricted by particular MHC alleles in preference to others. We have studied this poorly understood phenomenon using Theileria parva, a protozoan parasite that causes an often fatal lymphoproliferative disease in cattle. Despite its antigenic complexity, CD8+ T cell responses induced by infection with the parasite show profound immunodominance, as exemplified by the Tp1(214-224) epitope presented by the common and functionally important MHC class I allele N*01301. We present a high-resolution crystal structure of this pMHC complex, demonstrating that the peptide is presented in a distinctive raised conformation. Functional studies using CD8+ T cell clones show that this impacts significantly on TCR recognition. The unconventional structure is generated by a hydrophobic ridge within the MHC peptide binding groove, found in a set of cattle MHC alleles. Extremely rare in all other species, this feature is seen in a small group of mouse MHC class I molecules. The data generated in this analysis contribute to our understanding of the structural basis for T cell-dependent immune responses, providing insight into what determines a highly immunogenic p-MHC complex, and hence can be of value in prediction of antigenic epitopes and vaccine design.
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Affiliation(s)
- Isabel K. Macdonald
- The Jenner Institute, University of Oxford, Compton, Berkshire, United Kingdom
| | - Maria Harkiolaki
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
- * E-mail: (MH, for structural data); (SAE)
| | - Lawrence Hunt
- Institute for Animal Health, Compton, Berkshire, United Kingdom
| | - Timothy Connelley
- The Roslin Institute, Royal (Dick) School of Veterinary Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - A. Victoria Carroll
- The Roslin Institute, Royal (Dick) School of Veterinary Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Niall D. MacHugh
- The Roslin Institute, Royal (Dick) School of Veterinary Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Simon P. Graham
- Veterinary Laboratories Agency, Addlestone, Surrey, United Kingdom
| | - E. Yvonne Jones
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - W. Ivan Morrison
- The Roslin Institute, Royal (Dick) School of Veterinary Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Darren R. Flower
- The Jenner Institute, University of Oxford, Compton, Berkshire, United Kingdom
| | - Shirley A. Ellis
- Institute for Animal Health, Compton, Berkshire, United Kingdom
- * E-mail: (MH, for structural data); (SAE)
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7
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Brophy SE, Jones LL, Holler PD, Kranz DM. Cellular uptake followed by class I MHC presentation of some exogenous peptides contributes to T cell stimulatory capacity. Mol Immunol 2006; 44:2184-94. [PMID: 17169430 PMCID: PMC2547883 DOI: 10.1016/j.molimm.2006.11.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2006] [Accepted: 11/12/2006] [Indexed: 02/03/2023]
Abstract
The T cell stimulatory activity of peptides is known to be associated with the cell surface stability and lifetime of the peptide-MHC (pepMHC) complex. In this report, soluble high-affinity T cell receptors (TCRs) that are specific for pepMHC complexes recognized by the mouse CD8+ clone 2C were used to monitor the cell surface lifetimes of synthetic agonist peptides. In the 2C system, L(d)-binding peptide p2Ca (LSPFPFDL) has up to 10,000-fold lower activity than peptide QL9 (QLSPFPFDL) even though the 2C TCR binds to p2Ca-L(d) and QL9-L(d) complexes with similar affinities. Unexpectedly, p2Ca-L(d) complexes were found to have a longer cell surface lifetime than QL9-L(d) complexes. However, the strong agonist activity of QL9 correlated with its ability to participate in efficient intracellular delivery followed by cell surface expression of the peptide, resulting in high and persistent surface levels of QL9-L(d). The ability of target cells to take up and present QL9 was observed with TAP-deficient cells and TAP-positive cells, including dendritic cells. The process was brefeldin A-sensitive, indicating a requirement for transport of the pepMHC through the ER and/or golgi. Thus, strong T cell stimulatory activity of some pepMHC complexes can be accomplished not only through long cell surface lifetimes of the ligand, but through a mechanism that leads to delayed presentation of the exogenous antigen after intracellular uptake.
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Affiliation(s)
| | | | | | - David M. Kranz
- Author to whom correspondence should be sent: David M. Kranz, Department of Biochemistry, University of Illinois, 600 S. Matthews Ave., Urbana, IL 61801, Tel: 217-244-2821, Fax: 217-244-5858, E-mail:
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8
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Abstract
Classic major histocompatibility complex (MHC) proteins associate with antigen- and self-derived peptides in an allele-specific manner. Herein we present the crystal structure of the MHC class I protein H-2K(d) (K(d)) expressed by BALB/c mice in complex with an antigenic peptide derived from influenza A/PR/8/34 nucleoprotein (Flu, residues 147-155, TYQRTRALV). Analysis of our structure in conjunction with the sequences of naturally processed epitopes provides a comprehensive understanding of the dominant K(d) peptide-binding motif. We find that Flu residues Tyr(P2), Thr(P5), and Val(P9) are sequestered into the B, C, and F pockets of the K(d) groove, respectively. The shape and chemistry of the polymorphic B pocket make it an optimal binding site for the side chain of Tyr(P2) as the dominant anchoring residue of nonameric peptides. The non-polar F pocket limits the amino acid repertoire at P9 to hydrophobic residues such as Ile, Leu, or Val, whereas the C pocket restricts the size of the P5-anchoring side chain. We also show that Flu is accommodated in the complex through an unfavorable kink in the otherwise extended peptide backbone due to the presence of a prominent ridge in the K(d) groove. Surprisingly, this backbone conformation is strikingly similar to D(b)-presented peptides despite the fact that these proteins employ distinct motif-anchoring strategies. The results presented in this study provide a solid foundation for the understanding of K(d)-restricted antigen presentation and recognition events.
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Affiliation(s)
- Vesselin Mitaksov
- Department of Pathology and Immunology, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, USA
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9
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Brahic M, Bureau JF, Michiels T. The genetics of the persistent infection and demyelinating disease caused by Theiler's virus. Annu Rev Microbiol 2006; 59:279-98. [PMID: 16153171 DOI: 10.1146/annurev.micro.59.030804.121242] [Citation(s) in RCA: 117] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Theiler's virus causes a persistent and demyelinating infection of the central nervous system of the mouse, which is one of the best animal models to study multiple sclerosis. This review focuses on the mechanism of persistence. The virus infects neurons for a few weeks and then shifts to white matter, where it persists in glial cells and macrophages. Oligodendrocytes are crucial host cells, as shown by the resistance to persistent infection of mice bearing myelin mutations. Two viral proteins, L and L*, contribute to persistence by interfering with host defenses. L, a small zinc-finger protein, restricts the production of interferon. L*, a unique example of a picornaviral protein translated from an overlapping open reading frame, facilitates the infection of macrophages. Susceptibility to persistent infection, which varies among inbred mouse strains, is multigenic. H2 class I genes have a major effect on susceptibility. Among several non-H2 susceptibility loci, Tmevp3 appears to regulate the expression of important cytokines.
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Affiliation(s)
- Michel Brahic
- Unité des Virus Lents, URA CNRS 1930, Institut Pasteur, 75724 Paris Cedex 15, France.
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10
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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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Kellenberger C, Roussel A, Malissen B. The H-2KkMHC Peptide-Binding Groove Anchors the Backbone of an Octameric Antigenic Peptide in an Unprecedented Mode. THE JOURNAL OF IMMUNOLOGY 2005; 175:3819-25. [PMID: 16148128 DOI: 10.4049/jimmunol.175.6.3819] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
A wealth of data has accumulated on the structure of mouse MHC class I (MHCI) molecules encoded by the H-2(b) and H-2(d) haplotypes. In contrast, there is a dearth of structural data regarding H-2(k)-encoded molecules. Therefore, the structures of H-2K(k) complexed to an octameric peptide from influenza A virus (HA(259-266)) and to a nonameric peptide from SV40 (SV40(560-568)) have been determined by x-ray crystallography at 2.5 and 3.0 A resolutions, respectively. The structure of the H-2K(k)-HA(259-266) complex reveals that residues located on the floor of the peptide-binding groove contact directly the backbone of the octameric peptide and force it to lie deep within the H-2K(k) groove. This unprecedented mode of peptide binding occurs despite the presence of bulky residues in the middle of the floor of the H-2K(k) peptide-binding groove. As a result, the Calpha atoms of peptide residues P5 and P6 are more buried than the corresponding residues of H-2K(b)-bound octapeptides, making them even less accessible to TCR contact. When bound to H-2K(k), the backbone of the SV40(560-568) nonapeptide bulges out of the peptide-binding groove and adopts a conformation reminiscent of that observed for peptides bound to H-2L(d). This structural convergence occurs despite the totally different architectures of the H-2L(d) and H-2K(k) peptide-binding grooves. Therefore, these two H-2K(k)-peptide complexes provide insights into the mechanisms through which MHC polymorphism outside primary peptide pockets influences the conformation of the bound peptides and have implications for TCR recognition and vaccine design.
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Affiliation(s)
- Christine Kellenberger
- Centre d'Immunologie de Marseille-Luminy, Institut National de la Santé et de la Recherche Médicale-Centre National Recherche de la Scientifique-Université de la Méditerranée, Parc Scientifique de Luminy, Marseille, France.
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12
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Meijers R, Lai CC, Yang Y, Liu JH, Zhong W, Wang JH, Reinherz EL. Crystal structures of murine MHC Class I H-2 D(b) and K(b) molecules in complex with CTL epitopes from influenza A virus: implications for TCR repertoire selection and immunodominance. J Mol Biol 2004; 345:1099-110. [PMID: 15644207 DOI: 10.1016/j.jmb.2004.11.023] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2004] [Revised: 11/08/2004] [Accepted: 11/09/2004] [Indexed: 11/16/2022]
Abstract
Cytotoxic T lymphocyte (CTL) responses against influenza A virus in C57BL/6 mice are dominated by a small number of viral peptides among many that are capable of binding to major histocompatibility complex (MHC) class I molecules. The basis of this limited immune recognition is unknown. Here, we present X-ray structures of MHC class I molecules in complex with two immunodominant epitopes (PA(224-233)/D(b) and PB1(703-711)/K(b)) and one non-immunogenic epitope (HA(468-477)/D(b)) of the influenza A virus. The immunodominant peptides are each characterized by a bulge at the C terminus, lifting P6 and P7 residues out of the MHC groove, presenting featured structural elements to T-cell receptors (TCRs). Immune recognition of PA(224-233)/D(b) will focus largely on the exposed P7 arginine residue. In contrast, the non-immunogenic HA(468-477) peptide lacks prominent features in this C-terminal bulge. In the K(b)-bound PB1(703-711) epitope, the bulge results from a non-canonical binding motif, such that the mode of presentation of this peptide strongly resembles that of D(b)-bound peptides. Given that PA(224-233)/D(b), PB1(703-711)/K(b) and the previously defined NP(366-374)/D(b) epitopes dominate the primary response to influenza A virus in C57BL/6 mice, our findings indicate that residues of the C-terminal bulge are important in selection of the immunodominant CTL repertoire.
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Affiliation(s)
- Rob Meijers
- Laboratory of Immunobiology, Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115, USA
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Meulen JT, Badusche M, Satoguina J, Strecker T, Lenz O, Loeliger C, Sakho M, Koulemou K, Koivogui L, Hoerauf A. Old and New World arenaviruses share a highly conserved epitope in the fusion domain of the glycoprotein 2, which is recognized by Lassa virus-specific human CD4+ T-cell clones. Virology 2004; 321:134-43. [PMID: 15033572 DOI: 10.1016/j.virol.2003.12.013] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2003] [Revised: 11/12/2003] [Accepted: 12/04/2003] [Indexed: 11/23/2022]
Abstract
Data from human studies and animal experiments indicate a dominant role of T-cells over antibodies in controlling acute Lassa virus infection and providing immunity to reinfection. Knowledge of the epitopes recognized by T-cells may therefore be crucial to the development of a recombinant Lassa virus vaccine. In order to study human T-cell reactivity to the most conserved structural protein of Lassa virus, the glycoprotein 2 (GP2), seven GP2-specific CD4+ T-cell clones (TCCs) were generated from the lymphocytes of a Lassa antibody positive individual. All TCC displayed high specific proliferation, showed DR-restriction, and produced IFN-gamma upon stimulation with recombinant GP2. The epitope of four of the clones was localized to a short stretch of 13 amino acids located in the N-terminal part of GP2 (aa 289-301, numbering according to sequence of GPC). This epitope is conserved in all strains of Lassa virus and lymphocytic choriomeningitis virus (LCMV), shows >90% similarity in all New World arenaviruses of clade B, and overlaps with the proposed fusion domain of GP2. Peptides with conservative aa exchanges, as they naturally occur in the epitope 289-301 of the Old World arenavirus Mopeia and some New World arenaviruses, continued to effectively stimulate the Lassa-GP2-specific T-cell clones tested. The finding of a human T-helper cell epitope, which is highly conserved between Old and New World arenaviruses, is of importance for the design of arenavirus vaccines.
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Affiliation(s)
- Jan ter Meulen
- Institute of Virology, Philipps University, 35037 Marburg, Germany.
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14
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Ciatto C, Capitani G, Tissot AC, Pecorari F, Plückthun A, Grütter MG. Structural analysis of mycobacterial and murine hsp60 epitopes in complex with the class I MHC molecule H-2Db. FEBS Lett 2003; 543:11-5. [PMID: 12753896 DOI: 10.1016/s0014-5793(03)00325-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The decameric peptide SALQNAASIA from the Mycobacterium bovis heat shock protein (hsp) 60 is recognized by the murine T-cell receptor UZ-3-4 in complex with the murine class I major histocompatibility complex molecule H-2D(b). This T-cell receptor cross-reacts with the H-2D(b)-bound non-homologous decameric peptide KDIGNIISDA from the murine hsp60, but does not recognize the nonameric mycobacterial peptide SALQNAASI. Cross-recognition of the KDIGNIISDA/H-2D(b) complex induces autoimmune pathology in immunodeficient mice. We solved the X-ray crystal structure of the SALQNAASIA/H-2D(b) complex at 3.0 A resolution, and we modelled the KDIGNIISDA and SALQNAASI peptides in the H-2D(b) binding site. The structural analysis of the H-2D(b)-bound hsp60 epitopes offers insight into T-cell receptor cross-reactivity.
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Affiliation(s)
- Carlo Ciatto
- Department of Biochemistry, University of Zürich, Winterthurerstrasse 190, CH-8057, Zürich, Switzerland
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Hülsmeyer M, Hillig RC, Volz A, Rühl M, Schröder W, Saenger W, Ziegler A, Uchanska-Ziegler B. HLA-B27 Subtypes Differentially Associated with Disease Exhibit Subtle Structural Alterations. J Biol Chem 2002; 277:47844-53. [PMID: 12244049 DOI: 10.1074/jbc.m206392200] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The reasons for the association of the human major histocompatibility complex protein HLA-B27 with spondyloarthropathies are unknown. To uncover the underlying molecular causes, we determined the crystal structures of the disease-associated B*2705 and the nonassociated B*2709 subtypes complexed with the same nonapeptide (GRFAAAIAK). Both differ in only one residue (Asp(116) and His(116), respectively) in the F-pocket that accommodates the peptide C terminus. Several different effects of the Asp(116) --> His replacement are observed. The bulkier His(116) induces a movement of peptide C-terminal pLys(9), allowing the formation of a novel salt bridge to Asp(77), whereas the salt bridge between pLys(9) and Asp(116) is converted into a hydrogen bond with His(116). His(116) but not Asp(116) adopts two alternative conformations, one of which leads to breakage of hydrogen bonds. Water molecules near residue 116 differ with regard to number, position, and contacts made. Furthermore, F-pocket atoms exhibit higher B-factors in B*2709 than in B*2705, indicating an increased flexibility of the entire region in the former subtype. These changes induce subtle peptide conformational alterations that may be responsible for the immunobiological differences between these HLA-B27 subtypes.
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Affiliation(s)
- Martin Hülsmeyer
- Institut für Immungenetik, Universitätsklinikum Charité, Humboldt-Universität zu Berlin, Spandauer Damm 130, 14050 Berlin, Germany
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16
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Ogata K, Wodak SJ. Conserved water molecules in MHC class-I molecules and their putative structural and functional roles. Protein Eng Des Sel 2002; 15:697-705. [PMID: 12364585 DOI: 10.1093/protein/15.8.697] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
A set of conserved water positions making direct contacts with the alpha1 and alpha2 domains of the MHC class-I protein was identified by a cluster analysis in 12 high-resolution crystal structures of proteins from different allele types and different species, comprising human, mouse and rat. The analysis revealed a total of 63 clusters, corresponding to water molecules, whose positions are conserved in half or more of the analyzed structures. Analysis of these clusters shows that the most conserved water positions-those appearing in the largest fraction of the structures-were also the most accurately defined, as measured by their normalized crystallographic B-factor. Not too surprisingly, these positions displayed better overlap and formed more H-bonds with the protein. In a second part of this work, a detailed analysis is presented of three of the most conserved water positions and their putative structural and functional roles are discussed. The most highly conserved of the three appears to play an important role in stabilizing the conformation of a twisted beta-turn between residues 118 and 122 (numbering of HLA-B3501, PDB code 1A1N). An equivalent water molecule was found to be associated with a similar beta-turn in 43 unrelated structures surveyed in the PDB, leading to the suggestion that this water molecule plays an important structural role in this type of turn. The second water molecule makes hydrogen bonds with residues lining pocket B in the peptide-binding groove and is suggested to play a role in modulating peptide recognition. The third highly conserved water molecule is located at the first kink of the alpha2 helix, possibly playing a role in determining the position of the N-terminal segment of that helix, which also carries side chains in contact with the bound peptide. This information on conserved water positions in MHC class-I molecules should be helpful in modeling interactions with bound peptide antigens and in designing new peptides with tailor-made affinities.
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Affiliation(s)
- Koji Ogata
- Service de Conformation de Macromolécules Biologiques, Centre de Biologie Structurale et Bioinformatique, Université Libre de Bruxelles,av. F.D. Roosevelt 50, CP160/16, B-1050 Brussels, Belgium
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