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Tedeschi V, Paldino G, Alba J, Molteni E, Paladini F, Scrivo R, Congia M, Cauli A, Caccavale R, Paroli M, Di Franco M, Tuosto L, Sorrentino R, D’Abramo M, Fiorillo MT. ERAP1 and ERAP2 Haplotypes Influence Suboptimal HLA-B*27:05-Restricted Anti-Viral CD8+ T Cell Responses Cross-Reactive to Self-Epitopes. Int J Mol Sci 2023; 24:13335. [PMID: 37686141 PMCID: PMC10488187 DOI: 10.3390/ijms241713335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 08/22/2023] [Accepted: 08/25/2023] [Indexed: 09/10/2023] Open
Abstract
The human leukocyte antigen (HLA)-B*27 family of alleles is strongly associated with ankylosing spondylitis (AS), a chronic inflammatory disorder affecting the axial and peripheral joints, yet some HLA-B*27 variants not associated with AS have been shown. Since no major differences in the ligandome of associated compared to not-associated alleles have emerged, a plausible hypothesis is that the quantity rather than the quality of the presented epitopes makes the difference. In addition, the Endoplasmic Reticulum AminoPeptidases (ERAPs) 1 and 2, playing a crucial role in shaping the HLA class I epitopes, act as strong AS susceptibility factors, suggesting that an altered peptidome might be responsible for the activation of pathogenic CD8+ T cells. In this context, we have previously singled out a B*27:05-restricted CD8+ T cell response against pEBNA3A (RPPIFIRRL), an EBV peptide lacking the B*27 classic binding motif. Here, we show that a specific ERAP1/2 haplotype negatively correlates with such response in B*27:05 subjects. Moreover, we prove that the B*27:05 allele successfully presents peptides with the same suboptimal N-terminal RP motif, including the self-peptide, pDYNEIN (RPPIFGDFL). Overall, this study underscores the cooperation between the HLA-B*27 and ERAP1/2 allelic variants in defining CD8+ T cell reactivity to suboptimal viral and self-B*27 peptides and prompts further investigation of the B*27:05 peptidome composition.
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Affiliation(s)
- Valentina Tedeschi
- Department of Biology and Biotechnologies “Charles Darwin”, Sapienza University of Rome, 00185 Rome, Italy; (G.P.); (L.T.); (R.S.); (M.T.F.)
| | - Giorgia Paldino
- Department of Biology and Biotechnologies “Charles Darwin”, Sapienza University of Rome, 00185 Rome, Italy; (G.P.); (L.T.); (R.S.); (M.T.F.)
| | - Josephine Alba
- Department of Biology, University of Fribourg, Chemin du Musée, 1700 Fribourg, Switzerland;
| | - Emanuele Molteni
- Rheumatology Unit, Department of Clinical Internal, Anaesthesiological and Cardiovascular Sciences, Policlinico Umberto I, Sapienza University of Rome, 00161 Rome, Italy; (E.M.); (R.S.); (M.D.F.)
| | - Fabiana Paladini
- Department of Biology and Biotechnologies “Charles Darwin”, Sapienza University of Rome, 00185 Rome, Italy; (G.P.); (L.T.); (R.S.); (M.T.F.)
| | - Rossana Scrivo
- Rheumatology Unit, Department of Clinical Internal, Anaesthesiological and Cardiovascular Sciences, Policlinico Umberto I, Sapienza University of Rome, 00161 Rome, Italy; (E.M.); (R.S.); (M.D.F.)
| | - Mattia Congia
- Rheumatology Unit, AOU and University of Cagliari, 09042 Monserrato, Italy; (M.C.); (A.C.)
| | - Alberto Cauli
- Rheumatology Unit, AOU and University of Cagliari, 09042 Monserrato, Italy; (M.C.); (A.C.)
| | - Rosalba Caccavale
- Department of Biotechnology and Medical Surgical Sciences, Division of Clinical Immunology and Rheumatology, Sapienza University of Rome c/o Polo Pontino, 04100 Latina, Italy; (R.C.); (M.P.)
| | - Marino Paroli
- Department of Biotechnology and Medical Surgical Sciences, Division of Clinical Immunology and Rheumatology, Sapienza University of Rome c/o Polo Pontino, 04100 Latina, Italy; (R.C.); (M.P.)
| | - Manuela Di Franco
- Rheumatology Unit, Department of Clinical Internal, Anaesthesiological and Cardiovascular Sciences, Policlinico Umberto I, Sapienza University of Rome, 00161 Rome, Italy; (E.M.); (R.S.); (M.D.F.)
| | - Loretta Tuosto
- Department of Biology and Biotechnologies “Charles Darwin”, Sapienza University of Rome, 00185 Rome, Italy; (G.P.); (L.T.); (R.S.); (M.T.F.)
| | - Rosa Sorrentino
- Department of Biology and Biotechnologies “Charles Darwin”, Sapienza University of Rome, 00185 Rome, Italy; (G.P.); (L.T.); (R.S.); (M.T.F.)
| | - Marco D’Abramo
- Department of Chemistry, Sapienza University of Rome, 00185 Rome, Italy
| | - Maria Teresa Fiorillo
- Department of Biology and Biotechnologies “Charles Darwin”, Sapienza University of Rome, 00185 Rome, Italy; (G.P.); (L.T.); (R.S.); (M.T.F.)
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Lenart I, Truong LH, Nguyen DD, Rasiukienė O, Tsao E, Armstrong J, Kumar P, McHugh K, Pereira BI, Maan BS, Garstka MA, Bowness P, Blake N, Powis SJ, Gould K, Nesbeth D, Antoniou AN. Intrinsic Folding Properties of the HLA-B27 Heavy Chain Revealed by Single Chain Trimer Versions of Peptide-Loaded Class I Major Histocompatibility Complex Molecules. Front Immunol 2022; 13:902135. [PMID: 35958592 PMCID: PMC9359109 DOI: 10.3389/fimmu.2022.902135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Accepted: 06/14/2022] [Indexed: 11/13/2022] Open
Abstract
Peptide-loaded Major Histocompatibility Complex (pMHC) class I molecules can be expressed in a single chain trimeric (SCT) format, composed of a specific peptide fused to the light chain beta-2 microglobulin (β2m) and MHC class I heavy chain (HC) by flexible linker peptides. pMHC SCTs have been used as effective molecular tools to investigate cellular immunity and represent a promising vaccine platform technology, due to their intracellular folding and assembly which is apparently independent of host cell folding pathways and chaperones. However, certain MHC class I HC molecules, such as the Human Leukocyte Antigen B27 (HLA-B27) allele, present a challenge due to their tendency to form HC aggregates. We constructed a series of single chain trimeric molecules to determine the behaviour of the HLA-B27 HC in a scenario that usually allows for efficient MHC class I molecule folding. When stably expressed, a pMHC SCT incorporating HLA-B27 HC formed chaperone-bound homodimers within the endoplasmic reticulum (ER). A series of HLA-B27 SCT substitution mutations revealed that the F pocket and antigen binding groove regions of the HLA-B27 HC defined the folding and dimerisation of the single chain complex, independently of the peptide sequence. Furthermore, pMHC SCTs can demonstrate variability in their association with the intracellular antigen processing machinery.
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Affiliation(s)
- Izabela Lenart
- Division of Infection and Immunity/Centre of Rheumatology, University College London, London, United Kingdom
- Centre of Rheumatology, University College London, London, United Kingdom
- Clinical Trials and Regulatory Affairs, Science Pharma, Warsaw, Poland
| | - Linh-Huyen Truong
- Department of Applied Sciences, Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne, United Kingdom
- University of Oxford, Botnar Research Centre, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, Oxford, United Kingdom
| | - Dinh Dung Nguyen
- Department of Applied Sciences, Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne, United Kingdom
- Medical Genetics Department, Medical Genetics centre, Vinmec Research Institute of Stem Cell and Gene Technology, Hanoi, Vietnam
| | - Olga Rasiukienė
- Department of Applied Sciences, Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne, United Kingdom
| | - Edward Tsao
- Division of Infection and Immunity/Centre of Rheumatology, University College London, London, United Kingdom
| | - Jonathan Armstrong
- School of Medicine and Biological Sciences Research Complex, University of St. Andrews, Scotland, United Kingdom
| | - Pankaj Kumar
- School of Medicine and Biological Sciences Research Complex, University of St. Andrews, Scotland, United Kingdom
| | - Kirsty McHugh
- The Nuffield Department of Orthopaedics Rheumatology and Musculoskeletal Science, Oxford University, Oxford, United Kingdom
- Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Branca I. Pereira
- Division of Infection and Immunity/Centre of Rheumatology, University College London, London, United Kingdom
- Centre of Rheumatology, University College London, London, United Kingdom
- Research and Development Department, Chelsea and Westminster Hospital National Health Service (NHS) Foundation Trust, London, United Kingdom
| | - Balraj S. Maan
- Department of Applied Sciences, Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne, United Kingdom
- School of Medical Education, The Faculty of Medical Sciences, Newcastle University, Newcastle Upon Tyne, United Kingdom
| | - Malgorzata A. Garstka
- Core Research Laboratory, Department of Endocrinology, National & Local Joint Engineering Research Center of Biodiagnosis and Biotherapy, Second Affiliated Hospital, School of Medicine, Xi’an Jiaotong University, Xi’an, China
| | - Paul Bowness
- The Nuffield Department of Orthopaedics Rheumatology and Musculoskeletal Science, Oxford University, Oxford, United Kingdom
| | - Neil Blake
- Institute of Infection and Global Health, University of Liverpool, Liverpool, United Kingdom
| | - Simon J. Powis
- School of Medicine and Biological Sciences Research Complex, University of St. Andrews, Scotland, United Kingdom
| | - Keith Gould
- Wright-Fleming Institute, Imperial College London, London, United Kingdom
| | - Darren Nesbeth
- The Advanced Centre for Biochemical Engineering, University College London, London, United Kingdom
| | - Antony N. Antoniou
- Department of Applied Sciences, Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne, United Kingdom
- The Advanced Centre for Biochemical Engineering, University College London, London, United Kingdom
- *Correspondence: Antony N. Antoniou,
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Acid Stripping after Infection Improves the Detection of Viral HLA Class I Natural Ligands Identified by Mass Spectrometry. Int J Mol Sci 2021; 22:ijms221910503. [PMID: 34638844 PMCID: PMC8508920 DOI: 10.3390/ijms221910503] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 09/23/2021] [Accepted: 09/26/2021] [Indexed: 12/26/2022] Open
Abstract
Identification of a natural human leukocyte antigen (HLA) ligandome is a key element to understand the cellular immune response. Advanced high throughput mass spectrometry analyses identify a relevant, but not complete, fraction of the many tens of thousands of self-peptides generated by antigen processing in live cells. In infected cells, in addition to this complex HLA ligandome, a minority of peptides from degradation of the few proteins encoded by the viral genome are also bound to HLA class I molecules. In this study, the standard immunopeptidomics strategy was modified to include the classical acid stripping treatment after virus infection to enrich the HLA ligandome in virus ligands. Complexes of HLA-B*27:05-bound peptide pools were isolated from vaccinia virus (VACV)-infected cells treated with acid stripping after virus infection. The HLA class I ligandome was identified using high throughput mass spectrometry analyses, yielding 37 and 51 natural peptides processed and presented untreated and after acid stripping treatment VACV-infected human cells, respectively. Most of these virus ligands were identified in both conditions, but exclusive VACV ligands detected by mass spectrometry detected on acid stripping treatment doubled the number of those identified in the untreated VACV-infected condition. Theoretical binding affinity prediction of the VACV HLA-B*27:05 ligands and acute antiviral T cell response characterization in the HLA transgenic mice model showed no differences between HLA ligands identified under the two conditions: untreated and under acid stripping condition. These findings indicated that acid stripping treatment could be useful to identify HLA class I ligands from virus-infected cells.
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Tedeschi V, Paldino G, Paladini F, Mattorre B, Tuosto L, Sorrentino R, Fiorillo MT. The Impact of the 'Mis-Peptidome' on HLA Class I-Mediated Diseases: Contribution of ERAP1 and ERAP2 and Effects on the Immune Response. Int J Mol Sci 2020; 21:ijms21249608. [PMID: 33348540 PMCID: PMC7765998 DOI: 10.3390/ijms21249608] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 12/09/2020] [Accepted: 12/14/2020] [Indexed: 01/08/2023] Open
Abstract
The strong association with the Major Histocompatibility Complex (MHC) class I genes represents a shared trait for a group of autoimmune/autoinflammatory disorders having in common immunopathogenetic basis as well as clinical features. Accordingly, the main risk factors for Ankylosing Spondylitis (AS), prototype of the Spondyloarthropathies (SpA), the Behçet's disease (BD), the Psoriasis (Ps) and the Birdshot Chorioretinopathy (BSCR) are HLA-B*27, HLA-B*51, HLA-C*06:02 and HLA-A*29:02, respectively. Despite the strength of the association, the HLA pathogenetic role in these diseases is far from being thoroughly understood. Furthermore, Genome-Wide Association Studies (GWAS) have highlighted other important susceptibility factors such as Endoplasmic Reticulum Aminopeptidase (ERAP) 1 and, less frequently, ERAP2 that refine the peptidome presented by HLA class I molecules to CD8+ T cells. Mass spectrometry analysis provided considerable knowledge of HLA-B*27, HLA-B*51, HLA-C*06:02 and HLA-A*29:02 immunopeptidome. However, the combined effect of several ERAP1 and ERAP2 allelic variants could generate an altered pool of peptides accounting for the "mis-immunopeptidome" that ranges from suboptimal to pathogenetic/harmful peptides able to induce non-canonical or autoreactive CD8+ T responses, activation of NK cells and/or garbling the classical functions of the HLA class I molecules. This review will focus on this class of epitopes as possible elicitors of atypical/harmful immune responses which can contribute to the pathogenesis of chronic inflammatory diseases.
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Affiliation(s)
- Valentina Tedeschi
- Department of Biology and Biotechnology ‘Charles Darwin’, Sapienza University, 00185 Rome, Italy; (G.P.); (F.P.); (B.M.); (L.T.); (R.S.); (M.T.F.)
- Correspondence:
| | - Giorgia Paldino
- Department of Biology and Biotechnology ‘Charles Darwin’, Sapienza University, 00185 Rome, Italy; (G.P.); (F.P.); (B.M.); (L.T.); (R.S.); (M.T.F.)
| | - Fabiana Paladini
- Department of Biology and Biotechnology ‘Charles Darwin’, Sapienza University, 00185 Rome, Italy; (G.P.); (F.P.); (B.M.); (L.T.); (R.S.); (M.T.F.)
| | - Benedetta Mattorre
- Department of Biology and Biotechnology ‘Charles Darwin’, Sapienza University, 00185 Rome, Italy; (G.P.); (F.P.); (B.M.); (L.T.); (R.S.); (M.T.F.)
| | - Loretta Tuosto
- Department of Biology and Biotechnology ‘Charles Darwin’, Sapienza University, 00185 Rome, Italy; (G.P.); (F.P.); (B.M.); (L.T.); (R.S.); (M.T.F.)
- Laboratory Affiliated to Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Sapienza University, 00185 Rome, Italy
| | - Rosa Sorrentino
- Department of Biology and Biotechnology ‘Charles Darwin’, Sapienza University, 00185 Rome, Italy; (G.P.); (F.P.); (B.M.); (L.T.); (R.S.); (M.T.F.)
| | - Maria Teresa Fiorillo
- Department of Biology and Biotechnology ‘Charles Darwin’, Sapienza University, 00185 Rome, Italy; (G.P.); (F.P.); (B.M.); (L.T.); (R.S.); (M.T.F.)
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5
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Lorente E, Fontela MG, Barnea E, Martín-Galiano AJ, Mir C, Galocha B, Admon A, Lauzurica P, López D. Modulation of Natural HLA-B*27:05 Ligandome by Ankylosing Spondylitis-associated Endoplasmic Reticulum Aminopeptidase 2 (ERAP2). Mol Cell Proteomics 2020; 19:994-1004. [PMID: 32265295 PMCID: PMC7261815 DOI: 10.1074/mcp.ra120.002014] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Indexed: 12/20/2022] Open
Abstract
The HLA-B*27:05 allele and the endoplasmic reticulum-resident aminopeptidases are strongly associated with AS, a chronic inflammatory spondyloarthropathy. This study examined the effect of ERAP2 in the generation of the natural HLA-B*27:05 ligandome in live cells. Complexes of HLA-B*27:05-bound peptide pools were isolated from human ERAP2-edited cell clones, and the peptides were identified using high-throughput mass spectrometry analyses. The relative abundance of a thousand ligands was established by quantitative tandem mass spectrometry and bioinformatics analysis. The residue frequencies at different peptide position, identified in the presence or absence of ERAP2, determined structural features of ligands and their interactions with specific pockets of the antigen-binding site of the HLA-B*27:05 molecule. Sequence alignment of ligands identified with species of bacteria associated with HLA-B*27-dependent reactive arthritis was performed. In the absence of ERAP2, peptides with N-terminal basic residues and minority canonical P2 residues are enriched in the natural ligandome. Further, alterations of residue frequencies and hydrophobicity profile at P3, P7, and PΩ positions were detected. In addition, several ERAP2-dependent cellular peptides were highly similar to protein sequences of arthritogenic bacteria, including one human HLA-B*27:05 ligand fully conserved in a protein from Campylobacter jejuni These findings highlight the pathogenic role of this aminopeptidase in the triggering of AS autoimmune disease.
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Affiliation(s)
- Elena Lorente
- Unidad de Presentación y Regulación Inmunes, 28220 Majadahonda (Madrid), Spain
| | - Miguel G Fontela
- Unidad de Presentación y Regulación Inmunes, 28220 Majadahonda (Madrid), Spain
| | - Eilon Barnea
- Department of Biology, Technion-Israel Institute of Technology, 32000 Haifa, Israel
| | | | - Carmen Mir
- Unidad de Presentación y Regulación Inmunes, 28220 Majadahonda (Madrid), Spain
| | - Begoña Galocha
- Unidad de Presentación y Regulación Inmunes, 28220 Majadahonda (Madrid), Spain
| | - Arie Admon
- Department of Biology, Technion-Israel Institute of Technology, 32000 Haifa, Israel
| | - Pilar Lauzurica
- Unidad de Presentación y Regulación Inmunes, 28220 Majadahonda (Madrid), Spain
| | - Daniel López
- Unidad de Presentación y Regulación Inmunes, 28220 Majadahonda (Madrid), Spain.
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Tedeschi V, Alba J, Paladini F, Paroli M, Cauli A, Mathieu A, Sorrentino R, D'Abramo M, Fiorillo MT. Unusual Placement of an EBV Epitope into the Groove of the Ankylosing Spondylitis-Associated HLA-B27 Allele Allows CD8+ T Cell Activation. Cells 2019; 8:cells8060572. [PMID: 31212633 PMCID: PMC6627668 DOI: 10.3390/cells8060572] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 06/06/2019] [Accepted: 06/08/2019] [Indexed: 02/02/2023] Open
Abstract
The human leukocyte antigen HLA-B27 is a strong risk factor for Ankylosing Spondylitis (AS), an immune-mediated disorder affecting axial skeleton and sacroiliac joints. Additionally, evidence exists sustaining a strong protective role for HLA-B27 in viral infections. These two aspects could stem from common molecular mechanisms. Recently, we have found that the HLA-B*2705 presents an EBV epitope (pEBNA3A-RPPIFIRRL), lacking the canonical B27 binding motif but known as immunodominant in the HLA-B7 context of presentation. Notably, 69% of B*2705 carriers, mostly patients with AS, possess B*2705-restricted, pEBNA3A-specific CD8+ T cells. Contrarily, the non-AS-associated B*2709 allele, distinguished from the B*2705 by the single His116Asp polymorphism, is unable to display this peptide and, accordingly, B*2709 healthy subjects do not unleash specific T cell responses. Herein, we investigated whether the reactivity towards pEBNA3A could be a side effect of the recognition of the natural longer peptide (pKEBNA3A) having the classical B27 consensus (KRPPIFIRRL). The stimulation of PBMC from B*2705 positive patients with AS in parallel with both pEBNA3A and pKEBNA3A did not allow to reach an unambiguous conclusion since the differences in the magnitude of the response measured as percentage of IFNγ-producing CD8+ T cells were not statistically significant. Interestingly, computational analysis suggested a structural shift of pEBNA3A as well as of pKEBNA3A into the B27 grooves, leaving the A pocket partially unfilled. To our knowledge this is the first report of a viral peptide: HLA-B27 complex recognized by TCRs in spite of a partially empty groove. This implies a rethinking of the actual B27 immunopeptidome crucial for viral immune-surveillance and autoimmunity.
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Affiliation(s)
- Valentina Tedeschi
- Department of Biology and Biotechnology 'Charles Darwin', Sapienza University of Rome, 00185 Rome, Italy.
| | - Josephine Alba
- Department of Chemistry, Sapienza University of Rome, 00185 Rome, Italy.
| | - Fabiana Paladini
- Department of Biology and Biotechnology 'Charles Darwin', Sapienza University of Rome, 00185 Rome, Italy.
| | - Marino Paroli
- Division of Clinical Immunology and Rheumatology, Department of Biotechnology and Medical Surgical Sciences, Sapienza University of Rome, 00185 Rome, Italy.
| | - Alberto Cauli
- Rheumatology Unit, Department of Medical Sciences and Public Health, University and AOU of Cagliari, Monserrato, 09042 Cagliari, Italy.
| | - Alessandro Mathieu
- Rheumatology Unit, Department of Medical Sciences and Public Health, University and AOU of Cagliari, Monserrato, 09042 Cagliari, Italy.
| | - Rosa Sorrentino
- Department of Biology and Biotechnology 'Charles Darwin', Sapienza University of Rome, 00185 Rome, Italy.
| | - Marco D'Abramo
- Department of Chemistry, Sapienza University of Rome, 00185 Rome, Italy.
| | - Maria Teresa Fiorillo
- Department of Biology and Biotechnology 'Charles Darwin', Sapienza University of Rome, 00185 Rome, Italy.
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de Castro JAL, Stratikos E. Intracellular antigen processing by ERAP2: Molecular mechanism and roles in health and disease. Hum Immunol 2018; 80:310-317. [PMID: 30414458 DOI: 10.1016/j.humimm.2018.11.001] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Revised: 10/19/2018] [Accepted: 11/05/2018] [Indexed: 02/05/2023]
Abstract
Endoplasmic Reticulum Aminopeptidase 2 (ERAP2) is an intracellular enzyme localized in the ER that has been shown to play roles in the generation of peptides that serve as ligands for MHC class I (MHC-1) molecules. Although ERAP2 has been primarily described as an accessory and complementary enzyme to the homologous ERAP1, several lines of evidence during the last few years suggest that it can play distinct and important roles in processing antigenic peptides and influencing cellular cytotoxic immune responses. Such emerging evidence has been shaping ERAP2 as a potentially tractable target for regulating select autoimmune and anti-cancer responses for therapeutic purposes. Here, we review the state-of-the-art knowledge on the role of ERAP2 in antigen processing, its structure and molecular mechanism, influence on shaping MHC-I-bound immunopeptidomes and its involvement in disease pathogenesis.
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Affiliation(s)
- José A López de Castro
- Centro de Biología Molecular Severo Ochoa (Consejo Superior de Investigaciones Científicas and Universidad Autónoma), Madrid, Spain.
| | - Efstratios Stratikos
- National Centre for Scientific Research Demokritos, Agia Paraskevi, Athens, Greece.
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Serçinoğlu O, Ozbek P. Computational characterization of residue couplings and micropolymorphism-induced changes in the dynamics of two differentially disease-associated human MHC class-I alleles. J Biomol Struct Dyn 2017; 36:724-740. [DOI: 10.1080/07391102.2017.1295884] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Onur Serçinoğlu
- Department of Bioengineering, Institute of Pure and Applied Sciences, Marmara University, Istanbul, Turkey
- Faculty of Engineering, Department of Bioengineering, Marmara University, Istanbul, Turkey
| | - Pemra Ozbek
- Faculty of Engineering, Department of Bioengineering, Marmara University, Istanbul, Turkey
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9
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Barnea E, Melamed Kadosh D, Haimovich Y, Satumtira N, Dorris ML, Nguyen MT, Hammer RE, Tran TM, Colbert RA, Taurog JD, Admon A. The Human Leukocyte Antigen (HLA)-B27 Peptidome in Vivo, in Spondyloarthritis-susceptible HLA-B27 Transgenic Rats and the Effect of Erap1 Deletion. Mol Cell Proteomics 2017; 16:642-662. [PMID: 28188227 DOI: 10.1074/mcp.m116.066241] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Revised: 02/05/2017] [Indexed: 01/20/2023] Open
Abstract
HLA-B27 is a class I major histocompatibility (MHC-I) allele that confers susceptibility to the rheumatic disease ankylosing spondylitis (AS) by an unknown mechanism. ERAP1 is an aminopeptidase that trims peptides in the endoplasmic reticulum for binding to MHC-I molecules. ERAP1 shows genetic epistasis with HLA-B27 in conferring susceptibility to AS. Male HLA-B27 transgenic rats develop arthritis and serve as an animal model of AS, whereas female B27 transgenic rats remain healthy. We used large scale quantitative mass spectrometry to identify over 15,000 unique HLA-B27 peptide ligands, isolated after immunoaffinity purification of the B27 molecules from the spleens of HLA-B27 transgenic rats. Heterozygous deletion of Erap1, which reduced the Erap1 level to less than half, had no qualitative or quantitative effects on the B27 peptidome. Homozygous deletion of Erap1 affected approximately one-third of the B27 peptidome but left most of the B27 peptidome unchanged, suggesting the possibility that some of the HLA-B27 immunopeptidome is not processed in the presence of Erap1. Deletion of Erap1 was permissive for the AS-like phenotype, increased mean peptide length and increased the frequency of C-terminal hydrophobic residues and of N-terminal Ala, Ser, or Lys. The presence of Erap1 increased the frequency of C-terminal Lys and Arg, of Glu and Asp at intermediate residues, and of N-terminal Gly. Several peptides of potential interest in AS pathogenesis, previously identified in human cell lines, were isolated. However, rats susceptible to arthritis had B27 peptidomes similar to those of non-susceptible rats, and no peptides were found to be uniquely associated with arthritis. Whether specific B27-bound peptides are required for AS pathogenesis remains to be determined. Data are available via ProteomeXchange with identifier PXD005502.
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Affiliation(s)
- Eilon Barnea
- From the ‡Department of Biology, Technion-Israel Institute of Technology, Haifa 32000, Israel
| | - Dganit Melamed Kadosh
- From the ‡Department of Biology, Technion-Israel Institute of Technology, Haifa 32000, Israel
| | - Yael Haimovich
- From the ‡Department of Biology, Technion-Israel Institute of Technology, Haifa 32000, Israel
| | - Nimman Satumtira
- §Department of Internal Medicine, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390-8884
| | - Martha L Dorris
- §Department of Internal Medicine, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390-8884
| | - Mylinh T Nguyen
- ¶Department of Biochemistry, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390-8816
| | - Robert E Hammer
- ¶Department of Biochemistry, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390-8816
| | - Tri M Tran
- ‖NIAMS, National Institutes of Health, Bethesda, Maryland 20892-1560
| | - Robert A Colbert
- ‖NIAMS, National Institutes of Health, Bethesda, Maryland 20892-1560
| | - Joel D Taurog
- §Department of Internal Medicine, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390-8884;
| | - Arie Admon
- From the ‡Department of Biology, Technion-Israel Institute of Technology, Haifa 32000, Israel;
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Analysis of Major Histocompatibility Complex-Bound HIV Peptides Identified from Various Cell Types Reveals Common Nested Peptides and Novel T Cell Responses. J Virol 2016; 90:8605-20. [PMID: 27440904 DOI: 10.1128/jvi.00599-16] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Accepted: 07/13/2016] [Indexed: 12/18/2022] Open
Abstract
UNLABELLED Despite the critical role of epitope presentation for immune recognition, we still lack a comprehensive definition of HIV peptides presented by HIV-infected cells. Here we identified 107 major histocompatibility complex (MHC)-bound HIV peptides directly from the surface of live HIV-transfected 293T cells, HIV-infected B cells, and primary CD4 T cells expressing a variety of HLAs. The majority of peptides were 8 to 12 amino acids (aa) long and mostly derived from Gag and Pol. The analysis of the total MHC-peptidome and of HLA-A02-bound peptides identified new noncanonical HIV peptides of up to 16 aa that could not be predicted by HLA anchor scanning and revealed an heterogeneous surface peptidome. Nested sets of surface HIV peptides included optimal and extended HIV epitopes and peptides partly overlapping or distinct from known epitopes, revealing new immune responses in HIV-infected persons. Surprisingly, in all three cell types, a majority of Gag peptides derived from p15 rather than from the most immunogenic p24. The cytosolic degradation of peptide precursors in corresponding cells confirmed the generation of identified surface-nested peptides. Cytosolic degradation revealed peptides commonly produced in all cell types and displayed by various HLAs, peptides commonly produced in all cell types and selectively displayed by specific HLAs, and peptides produced in only one cell type. Importantly, we identified areas of proteins leading to common presentations of noncanonical peptides by several cell types with distinct HLAs. These peptides may benefit the design of immunogens, focusing T cell responses on relevant markers of HIV infection in the context of HLA diversity. IMPORTANCE The recognition of HIV-infected cells by immune T cells relies on the presentation of HIV-derived peptides by diverse HLA molecules at the surface of cells. The landscape of HIV peptides displayed by HIV-infected cells is not well defined. Considering the diversity of HLA molecules in the human population, it is critical for vaccine design to identify HIV peptides that may be displayed despite the HLA diversity. We identified 107 HIV peptides directly from the surface of three cell types infected with HIV. They corresponded to nested sets of HIV peptides of canonical and novel noncanonical lengths not predictable by the presence of HLA anchors. Importantly, we identified areas of HIV proteins leading to presentation of noncanonical peptides by several cell types with distinct HLAs. Including such peptides in vaccine immunogen may help to focus immune responses on common markers of HIV infection in the context of HLA diversity.
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Schittenhelm RB, Sivaneswaran S, Lim Kam Sian TCC, Croft NP, Purcell AW. Human Leukocyte Antigen (HLA) B27 Allotype-Specific Binding and Candidate Arthritogenic Peptides Revealed through Heuristic Clustering of Data-independent Acquisition Mass Spectrometry (DIA-MS) Data. Mol Cell Proteomics 2016; 15:1867-76. [PMID: 26929215 DOI: 10.1074/mcp.m115.056358] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Indexed: 01/07/2023] Open
Abstract
Expression of HLA-B27 is strongly associated with ankylosing spondylitis (AS) and other spondyloarthropathies. While this is true for the majority of HLA-B27 allotypes, HLA-B*27:06 and HLA-B*27:09 are not associated with AS. These two subtypes contain polymorphisms that are ideally positioned to influence the bound peptide repertoire. The existence of disease-inducing peptides (so-called arthritogenic peptides) has therefore been proposed that are exclusively presented by disease-associated HLA-B27 allotypes. However, we have recently demonstrated that this segregation of allotype-bound peptides is not the case and that many peptides that display sequence features predicted to favor binding to disease-associated subtypes are also capable of being presented naturally by protective alleles. To further probe more subtle quantitative changes in peptide presentation, we have used a combination of data-independent acquisition (DIA) and multiple reaction monitoring (MRM) mass spectrometry to quantify the abundance of 1646 HLA-B27 restricted peptides across the eight most frequent HLA-B27 allotypes (HLA-B*27:02-HLA-B*27:09). We utilized K means cluster analysis to group peptides with similar allelic binding preferences across the eight HLA-B27 allotypes, which enabled us to identify the most-stringent binding characteristics for each HLA-B27 allotype and further refined their existing consensus-binding motifs. Moreover, a thorough analysis of this quantitative dataset led to the identification of 26 peptides, which are presented in lower abundance by HLA-B*27:06 and HLA-B*27:09 compared with disease-associated HLA-B27 subtypes. Although these differences were observed to be very subtle, these 26 peptides might encompass the sought-after arthritogenic peptide(s).
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Affiliation(s)
- Ralf B Schittenhelm
- From the ‡Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC 3800, Australia
| | - Saranjah Sivaneswaran
- From the ‡Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC 3800, Australia
| | - Terry C C Lim Kam Sian
- From the ‡Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC 3800, Australia
| | - Nathan P Croft
- From the ‡Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC 3800, Australia
| | - Anthony W Purcell
- From the ‡Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC 3800, Australia
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Schittenhelm RB, Sian TCCLK, Wilmann PG, Dudek NL, Purcell AW. Revisiting the arthritogenic peptide theory: quantitative not qualitative changes in the peptide repertoire of HLA-B27 allotypes. Arthritis Rheumatol 2015; 67:702-13. [PMID: 25418920 DOI: 10.1002/art.38963] [Citation(s) in RCA: 86] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Accepted: 11/11/2014] [Indexed: 01/07/2023]
Abstract
OBJECTIVE The association of HLA-B27 with spondyloarthropathy is one of the strongest documented for any autoimmune disease. A common hypothesis for this association is the arthritogenic peptide concept. This dictates that differences in the peptide binding preferences of disease-associated and non-disease-associated HLA-B27 allotypes underlie the presentation of bacterial and self-peptides, leading to cross-reactive T cell immunity and subsequent autoimmune attack of affected tissues. The aim of this study was to analyze and compare self-peptides from 8 HLA-B27 allotypes, to increase existing data sets of HLA-B27 ligands, to refine and compare their consensus-binding motifs, and to reveal similarities and differences in the peptide repertoire of the HLA-B27 subtypes. METHODS Qualitative differences in the peptides bound to the 8 most frequent HLA-B27 subtypes were determined by tandem mass spectrometry, and quantitative changes in allelic binding specificities were determined by highly sensitive and targeted multiple reaction monitoring mass spectrometry. RESULTS We identified >7,500 major histocompatibility complex class I peptides derived from the 8 most common HLA-B27 allotypes (HLA-B*27:02 to HLA-B*27:09). We describe individual binding motifs for these alleles for the 9-12-mer ligands. The peptide repertoires of these closely related alleles showed significant overlap. Allelic polymorphisms resulting in changes in the amino acid composition of the antigen-binding cleft manifested largely as quantitative changes in the peptide cargo of these molecules. CONCLUSION Absolute binding preferences of HLA-B27 allotypes do not explain disease association. The arthritogenic peptide theory needs to be reassessed in terms of quantitative changes in self-peptide presentation, T cell selection, and altered conformation of bound peptides.
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García-Medel N, Sanz-Bravo A, Alvarez-Navarro C, Gómez-Molina P, Barnea E, Marcilla M, Admon A, de Castro JAL. Peptide handling by HLA-B27 subtypes influences their biological behavior, association with ankylosing spondylitis and susceptibility to endoplasmic reticulum aminopeptidase 1 (ERAP1). Mol Cell Proteomics 2014; 13:3367-80. [PMID: 25187574 DOI: 10.1074/mcp.m114.039214] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
HLA-B27 is strongly associated with ankylosing spondylitis (AS). We analyzed the relationship between structure, peptide specificity, folding, and stability of the seven major HLA-B27 subtypes to determine the role of their constitutive peptidomes in the pathogenicity of this molecule. Identification of large numbers of ligands allowed us to define the differences among subtype-bound peptidomes and to elucidate the peptide features associated with AS and molecular stability. The peptides identified only in AS-associated or high thermostability subtypes with identical A and B pockets were longer and had bulkier and more diverse C-terminal residues than those found only among non-AS-associated/lower-thermostability subtypes. Peptides sequenced from all AS-associated subtypes and not from non-AS-associated ones, thus strictly correlating with disease, were very rare. Residue 116 was critical in determining peptide binding, thermodynamic properties, and folding, thus emerging as a key feature that unified HLA-B27 biology. HLA-B27 ligands were better suited to TAP transport than their N-terminal precursors, and AS-associated subtype ligands were better than those from non-AS-associated subtypes, suggesting a particular capacity of AS-associated subtypes to bind epitopes directly produced in the cytosol. Peptides identified only from AS-associated/high-thermostability subtypes showed a higher frequency of ERAP1-resistant N-terminal residues than ligands found only in non-AS-associated/low-thermostability subtypes, reflecting a more pronounced effect of ERAP1 on the former group. Our results reveal the basis for the relationship between peptide specificity and other features of HLA-B27, provide a unified view of HLA-B27 biology and pathogenicity, and suggest a larger influence of ERAP1 polymorphism on AS-associated than non-AS-associated subtypes.
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Affiliation(s)
- Noel García-Medel
- From the ‡Centro de Biología Molecular Severo Ochoa (Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid), Madrid, Spain
| | - Alejandro Sanz-Bravo
- From the ‡Centro de Biología Molecular Severo Ochoa (Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid), Madrid, Spain
| | - Carlos Alvarez-Navarro
- From the ‡Centro de Biología Molecular Severo Ochoa (Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid), Madrid, Spain
| | - Patricia Gómez-Molina
- From the ‡Centro de Biología Molecular Severo Ochoa (Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid), Madrid, Spain
| | - Eilon Barnea
- §Faculty of Biology, Technion-Israel Institute of Technology, Haifa 32000, Israel
| | - Miguel Marcilla
- ¶Functional Proteomics Unit. Centro Nacional de Biotecnología (Consejo Superior de Investigaciones Científicas), Madrid, Spain
| | - Arie Admon
- §Faculty of Biology, Technion-Israel Institute of Technology, Haifa 32000, Israel
| | - José A López de Castro
- From the ‡Centro de Biología Molecular Severo Ochoa (Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid), Madrid, Spain;
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Nitschke K, Barriga A, Schmidt J, Timm J, Viazov S, Kuntzen T, Kim AY, Lauer GM, Allen TM, Gaudieri S, Rauch A, Lange CM, Sarrazin C, Eiermann T, Sidney J, Sette A, Thimme R, López D, Neumann-Haefelin C. HLA-B*27 subtype specificity determines targeting and viral evolution of a hepatitis C virus-specific CD8+ T cell epitope. J Hepatol 2014; 60:22-9. [PMID: 23978718 PMCID: PMC3867523 DOI: 10.1016/j.jhep.2013.08.009] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2013] [Revised: 07/29/2013] [Accepted: 08/02/2013] [Indexed: 01/17/2023]
Abstract
BACKGROUND & AIMS HLA-B*27 is associated with spontaneous HCV genotype 1 clearance. HLA-B*27-restricted CD8+ T cells target three NS5B epitopes. Two of these epitopes are dominantly targeted in the majority of HLA-B*27+ patients. In chronic infection, viral escape occurs consistently in these two epitopes. The third epitope (NS5B2820) was dominantly targeted in an acutely infected patient. This was in contrast, however, to the lack of recognition and viral escape in the large majority of HLA-B*27+ patients. Here, we set out to determine the host factors contributing to selective targeting of this epitope. METHODS Four-digit HLA class I typing and viral sequence analyses were performed in 78 HLA-B*27+ patients with chronic HCV genotype 1 infection. CD8+ T cell analyses were performed in a subset of patients. In addition, HLA/peptide affinity was compared for HLA-B*27:02 and 05. RESULTS The NS5B2820 epitope is only restricted by the HLA-B*27 subtype HLA-B*27:02 (that is frequent in Mediterranean populations), but not by the prototype HLA-B*27 subtype B*27:05. Indeed, the epitope is very dominant in HLA-B*27:02+ patients and is associated with viral escape mutations at the anchor position for HLA-binding in 12 out of 13 HLA-B*27:02+ chronically infected patients. CONCLUSIONS The NS5B2820 epitope is immunodominant in the context of HLA-B*27:02, but is not restricted by other HLA-B*27 subtypes. This finding suggests an important role of HLA subtypes in the restriction of HCV-specific CD8+ responses. With minor HLA subtypes covering up to 39% of specific populations, these findings may have important implications for the selection of epitopes for global vaccines.
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Affiliation(s)
- Katja Nitschke
- Department of Medicine II, University of Freiburg, Freiburg, Germany,Faculty of Biology, University of Freiburg, Freiburg, Germany
| | | | - Julia Schmidt
- Department of Medicine II, University of Freiburg, Freiburg, Germany
| | - Jörg Timm
- Institute of Virology, University Hospital, University of Duisburg-Essen, Essen, Germany
| | - Sergei Viazov
- Institute of Virology, University Hospital, University of Duisburg-Essen, Essen, Germany
| | - Thomas Kuntzen
- Ragon Institute of MGH, MIT and Harvard, Charlestown, MA, USA
| | - Arthur Y. Kim
- Division of Infectious Diseases, MGH, Boston, MA, USA
| | | | - Todd M. Allen
- Ragon Institute of MGH, MIT and Harvard, Charlestown, MA, USA
| | - Silvana Gaudieri
- School of Anatomy, Physiology and Human Biology, University of Western Australia, Perth Australia,Institute of Immunology and Infectious Disease, Murdoch University, Perth, Western Australia, Australia
| | - Andri Rauch
- Department of Infectious Diseases, Bern University Hospital and University of Bern, Switzerland
| | - Christian M. Lange
- Department of Medicine I, J. W. Goethe University Hospital, Frankfurt, Germany
| | - Christoph Sarrazin
- Department of Medicine I, J. W. Goethe University Hospital, Frankfurt, Germany
| | - Thomas Eiermann
- Transfusion Medicine, HLA-Laboratory, University Hospital Hamburg-Eppendorf, Hamburg, Germany
| | - John Sidney
- La Jolla Institute for Allergy and Immunology, La Jolla, CA, USA
| | - Alessandro Sette
- La Jolla Institute for Allergy and Immunology, La Jolla, CA, USA
| | - Robert Thimme
- Department of Medicine II, University of Freiburg, Freiburg, Germany
| | - Daniel López
- Instituto de Salud Carlos III, Majadahonda, Madrid, Spain
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Short peptide sequence identity between human viruses and HLA-B27-binding human 'self' peptides. Theory Biosci 2013; 133:79-89. [PMID: 24362932 DOI: 10.1007/s12064-013-0196-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2013] [Accepted: 12/02/2013] [Indexed: 10/25/2022]
Abstract
Molecular mimicry and arthritogenic peptides form the basis of hypotheses that attempt to explain the pathogenesis of HLA-B27-positive ankylosing spondylitis (AS). We propose, therefore, that certain human viruses may possess peptide sequences that mimic HLA-B27-binding human 'self' peptides which might induce or play a significant role in AS. In the present study, we performed bioinformatic analysis, using BLASTP, of the human virus proteome and HLA-B27-binding human 'self' peptides including peptides derived from arthritogenic sequences. We identified that some HLA-B27-binding peptides, particularly those present in proteins of the cartilage and bone, are highly similar to those present in viruses known to cause chronic infection. We suggest that the identical short amino acid sequences shared between human viruses and HLA-B27 peptides may play a role in the pathogenesis of AS.
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Sorrentino R, Böckmann RA, Fiorillo MT. HLA-B27 and antigen presentation: at the crossroads between immune defense and autoimmunity. Mol Immunol 2013; 57:22-7. [PMID: 23916069 DOI: 10.1016/j.molimm.2013.06.017] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Revised: 06/17/2013] [Accepted: 06/18/2013] [Indexed: 10/26/2022]
Abstract
The HLA-B27 is historically studied as a susceptibility factor in spondyloarthropathies and, primarily, in ankylosing spondylitis (AS). Over the recent years however, it has been rediscovered as protective factor against some severe viral infections. This is due to the high capacity of virus-specific, HLA-B27-restricted CD8+ T cells for both intrinsic (i.e. polyfunctionality, high avidity, low sensitivity to Treg cell-mediated suppression) and extrinsic (i.e. rapid and efficient antigen processing and presentation) factors. It is tempting to speculate that these two aspects are not independent and that the association of B27 molecules to autoimmunity is the downside of this superior functional efficacy which, in given genetic backgrounds and environmental conditions, can support a chronic inflammation leading to spondyloarthropathies. Still, the pathogenic role of HLA-B27 molecules in AS is elusive. Here, we focus on the biology of HLA-B27 from the genetics to the biochemistry and to the structural/dynamical properties of B27:peptide complexes as obtained from atomistic molecular dynamics simulation. Overall, the results point at the antigen presentation as the key event in the disease pathogenesis. In particular, an extensive comparison of HLA-B*2705 and B*2709 molecules, that differ in a single amino acid (Asp116 to His116) and are differentially associated with AS, indicates that position 116 is crucial for shaping the entire peptide-presenting groove.
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Affiliation(s)
- Rosa Sorrentino
- Istituto Pasteur-Fondazione Cenci Bolognetti, Sapienza, University of Rome, Italy; Department of Biology and Biotechnology "C. Darwin", Sapienza, University of Rome, Italy
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