1
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Iesa M, Osman M, Hassan M, Dirar A, Abuzeid N, Mancuso J, Pandey R, Mohammed A, Borad M, Babiker H, Konozy E. SARS-CoV-2 and Plasmodium falciparum common immunodominant regions may explain low COVID-19 incidence in the malaria-endemic belt. New Microbes New Infect 2020; 38:100817. [PMID: 33230417 PMCID: PMC7674012 DOI: 10.1016/j.nmni.2020.100817] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 11/10/2020] [Accepted: 11/12/2020] [Indexed: 12/15/2022] Open
Abstract
Coronavirus disease 2019 (COVID-19) has caused significant morbidity and mortality and new cases are on the rise globally, yet malaria-endemic areas report statistically significant lower incidences. We identified potential shared targets for an immune response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) by immune determinants' shared identities with P. falciparum using the Immune Epitope Database and Analysis Resource Immune 9.0 browser tool. Probable cross-reactivity is suggested through HLA-A∗02:01 and subsequent CD8+ T-cell activation. The apparent immunodominant epitope conservation between SARS-CoV-2 (N and open reading frame (ORF) 1ab) and P. falciparum thrombospondin-related anonymous protein (TRAP) may underlie the low COVID-19 incidence in the malaria-endemic zone by providing immunity against virus infection to those previously infected with Plasmodium. Additionally, we hypothesize that the shared epitopes which lie within antigens that aid in the establishment of the P. falciparum erythrocyte invasion may be an alternative route for SARS-CoV-2 via the erythrocyte CD147 receptor, although this remains to be proven.
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Affiliation(s)
- M.A.M. Iesa
- Department of Physiology, Al Qunfudah Medical College, Umm Al Qura University, Mecca, Saudi Arabia
| | - M.E.M. Osman
- Department of Zoology, Faculty of Science, University of Khartoum, Khartoum, Sudan
| | - M.A. Hassan
- Department of Translation Bioinformatics, DetaVax Biotech, Kayseri, Turkey
| | - A.I.A. Dirar
- Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto City, Japan
| | - N. Abuzeid
- Department of Medical Microbiology, Faculty of Medical Laboratory of Sciences, Omdurman University, Khartoum, Sudan
| | - J.J. Mancuso
- Department of Immunology, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - R. Pandey
- Department of Cellular and Molecular Medicine, University of Arizona Cancer Center, Tucson, AZ, USA
| | - A.A. Mohammed
- Biotechnology Department, Africa City of Technology, Khartoum, Sudan
| | - M.J. Borad
- Department of Medicine, Division of Hematology-Oncology, Mayo Clinic, Scottsdale, AZ, USA
| | - H.M. Babiker
- Department of Medicine, Division of Hematology-Oncology, University of Arizona Cancer Center, AZ, USA
| | - E.H.E. Konozy
- Biotechnology Department, Africa City of Technology, Khartoum, Sudan
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2
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Fernandes RA, Li C, Wang G, Yang X, Savvides CS, Glassman CR, Dong S, Luxenberg E, Sibener LV, Birnbaum ME, Benoist C, Mathis D, Garcia KC. Discovery of surrogate agonists for visceral fat Treg cells that modulate metabolic indices in vivo. eLife 2020; 9:58463. [PMID: 32773038 PMCID: PMC7440915 DOI: 10.7554/elife.58463] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 08/04/2020] [Indexed: 12/22/2022] Open
Abstract
T regulatory (Treg) cells play vital roles in modulating immunity and tissue homeostasis. Their actions depend on TCR recognition of peptide-MHC molecules; yet the degree of peptide specificity of Treg-cell function, and whether Treg ligands can be used to manipulate Treg cell biology are unknown. Here, we developed an Ab-peptide library that enabled unbiased screening of peptides recognized by a bona fide murine Treg cell clone isolated from the visceral adipose tissue (VAT), and identified surrogate agonist peptides, with differing affinities and signaling potencies. The VAT-Treg cells expanded in vivo by one of the surrogate agonists preserved the typical VAT-Treg transcriptional programs. Immunization with this surrogate, especially when coupled with blockade of TNFα signaling, expanded VAT-Treg cells, resulting in protection from inflammation and improved metabolic indices, including promotion of insulin sensitivity. These studies suggest that antigen-specific targeting of VAT-localized Treg cells could eventually be a strategy for improving metabolic disease.
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Affiliation(s)
- Ricardo A Fernandes
- Departments of Molecular and Cellular Physiology and Structural Biology, Stanford University School of Medicine, Stanford, United States
| | - Chaoran Li
- Department of Immunology, Harvard Medical School; and Evergrande Center for Immunologic Diseases, Harvard Medical School and Brigham and Women's Hospital, Boston, United States
| | - Gang Wang
- Department of Immunology, Harvard Medical School; and Evergrande Center for Immunologic Diseases, Harvard Medical School and Brigham and Women's Hospital, Boston, United States
| | - Xinbo Yang
- Departments of Molecular and Cellular Physiology and Structural Biology, Stanford University School of Medicine, Stanford, United States
| | - Christina S Savvides
- Departments of Molecular and Cellular Physiology and Structural Biology, Stanford University School of Medicine, Stanford, United States
| | - Caleb R Glassman
- Departments of Molecular and Cellular Physiology and Structural Biology, Stanford University School of Medicine, Stanford, United States
| | - Shen Dong
- Departments of Molecular and Cellular Physiology and Structural Biology, Stanford University School of Medicine, Stanford, United States
| | - Eric Luxenberg
- Department of Electrical Engineering, Stanford University School of Engineering, Stanford, United States
| | - Leah V Sibener
- Departments of Molecular and Cellular Physiology and Structural Biology, Stanford University School of Medicine, Stanford, United States
| | - Michael E Birnbaum
- Departments of Molecular and Cellular Physiology and Structural Biology, Stanford University School of Medicine, Stanford, United States
| | - Christophe Benoist
- Department of Immunology, Harvard Medical School; and Evergrande Center for Immunologic Diseases, Harvard Medical School and Brigham and Women's Hospital, Boston, United States
| | - Diane Mathis
- Department of Immunology, Harvard Medical School; and Evergrande Center for Immunologic Diseases, Harvard Medical School and Brigham and Women's Hospital, Boston, United States
| | - K Christopher Garcia
- Departments of Molecular and Cellular Physiology and Structural Biology, Stanford University School of Medicine, Stanford, United States.,Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, United States
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3
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Paprckova D, Stepanek O. Narcissistic T cells: reactivity to self makes a difference. FEBS J 2020; 288:1778-1788. [PMID: 32738029 DOI: 10.1111/febs.15498] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 06/22/2020] [Accepted: 07/25/2020] [Indexed: 12/15/2022]
Abstract
It has been appreciated for more than three decades that the interactions between the T-cell antigen receptor and self-antigens are the major determinants of the cell fates of developing thymocytes and the establishment of central tolerance. However, recent evidence shows that the level of self-reactivity substantially contributes to fate choices of positively selected mature T cells in homeostasis, as well as during immune responses. This implies that individual clones of peripheral T cells are predisposed to specific functional properties based on the self-reactivity of their antigen receptors. Overall, the relative difference in the self-reactivity among peripheral T cells is an important factor contributing to the diversity of T-cell responses to foreign antigens.
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Affiliation(s)
- Darina Paprckova
- Laboratory of Adaptive Immunity, Institute of Molecular Genetics, Czech Academy of Sciences, Prague, Czech Republic
| | - Ondrej Stepanek
- Laboratory of Adaptive Immunity, Institute of Molecular Genetics, Czech Academy of Sciences, Prague, Czech Republic
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4
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Matson CA, Singh NJ. Manipulating the TCR signaling network for cellular immunotherapy: Challenges & opportunities. Mol Immunol 2020; 123:64-73. [PMID: 32422416 DOI: 10.1016/j.molimm.2020.04.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Revised: 02/24/2020] [Accepted: 04/11/2020] [Indexed: 02/06/2023]
Abstract
T cells can help confer protective immunity by eliminating infections and tumors or drive immunopathology by damaging host cells. Both outcomes require a series of steps from the activation of naïve T cells to their clonal expansion, differentiation and migration to tissue sites. In addition to specific recognition of the antigen via the T cell receptor (TCR), multiple accessory signals from costimulatory molecules, cytokines and metabolites also influence each step along the progression of the T cell response. Current efforts to modify effector T cell function in many clinical contexts focus on the latter - which encompass antigen-independent and broad, contextual regulators. Not surprisingly, such approaches are often accompanied by adverse events, as they also affect T cells not relevant to the specific treatment. In contrast, fine tuning T cell responses by precisely targeting antigen-specific TCR signals has the potential to radically alter therapeutic strategies in a focused manner. Development of such approaches, however, requires a better understanding of functioning of the TCR and the biochemical signaling network coupled to it. In this article, we review some of the recent advances which highlight important roles of TCR signals throughout the activation and differentiation of T cells during an immune response. We discuss how, an appreciation of specific signaling modalities and variant ligands that influence the function of the TCR has the potential to influence design principles for the next generation of pharmacologic and cellular therapies, especially in the context of tumor immunotherapies involving adoptive cell transfers.
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Affiliation(s)
- Courtney A Matson
- Department of Microbiology & Immunology, University of Maryland School of Medicine, 685 W Baltimore St, HSF1, Room 380, Baltimore, MD 21201, United States
| | - Nevil J Singh
- Department of Microbiology & Immunology, University of Maryland School of Medicine, 685 W Baltimore St, HSF1, Room 380, Baltimore, MD 21201, United States.
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5
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Vandamme C, Xicluna R, Hesnard L, Devaux M, Jaulin N, Guilbaud M, Le Duff J, Couzinié C, Moullier P, Saulquin X, Adjali O. Tetramer-Based Enrichment of Preexisting Anti-AAV8 CD8 + T Cells in Human Donors Allows the Detection of a T EMRA Subpopulation. Front Immunol 2020; 10:3110. [PMID: 32038634 PMCID: PMC6990124 DOI: 10.3389/fimmu.2019.03110] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Accepted: 12/20/2019] [Indexed: 12/26/2022] Open
Abstract
Pre-existing immunity to AAV capsid may compromise the safety and efficiency of rAAV-mediated gene transfer in patients. Anti-capsid cytotoxic immune responses have proven to be a challenge to characterize because of the scarcity of circulating AAV-specific CD8+ T lymphocytes which can seldom be detected with conventional flow cytometry or ELISpot assays. Here, we used fluorescent MHC class I tetramers combined with magnetic enrichment to detect and phenotype AAV8-specific CD8+ T cells in human PBMCs without prior amplification. We showed that all healthy individuals tested carried a pool of AAV8-specific CD8+ T cells with a CD45RA+ CCR7- terminally-differentiated effector memory cell (TEMRA) fraction. Ex vivo frequencies of total AAV-specific CD8+ T cells were not predictive of IFNγ ELISpot responses but interestingly we evidenced a correlation between the proportion of TEMRA cells and IFNγ ELISpot positive responses. TEMRA cells may then play a role in recombinant AAV-mediated cytotoxicity in patients with preexisting immunity. Overall, our results encourage the development of new methods combining increased detection sensitivity of AAV-specific T cells and their poly-functional assessment to better characterize and monitor AAV capsid-specific cellular immune responses in the perspective of rAAV-mediated clinical trials.
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Affiliation(s)
- Céline Vandamme
- INSERM UMR 1089, Université de Nantes, CHU de Nantes, Nantes, France
| | - Rebecca Xicluna
- INSERM UMR 1089, Université de Nantes, CHU de Nantes, Nantes, France
| | - Leslie Hesnard
- CRCINA, INSERM, CNRS, Université d'Angers, Université de Nantes, Nantes, France
| | - Marie Devaux
- INSERM UMR 1089, Université de Nantes, CHU de Nantes, Nantes, France
| | - Nicolas Jaulin
- INSERM UMR 1089, Université de Nantes, CHU de Nantes, Nantes, France
| | - Mickaël Guilbaud
- INSERM UMR 1089, Université de Nantes, CHU de Nantes, Nantes, France
| | - Johanne Le Duff
- INSERM UMR 1089, Université de Nantes, CHU de Nantes, Nantes, France
| | - Célia Couzinié
- INSERM UMR 1089, Université de Nantes, CHU de Nantes, Nantes, France
| | - Philippe Moullier
- INSERM UMR 1089, Université de Nantes, CHU de Nantes, Nantes, France
| | - Xavier Saulquin
- CRCINA, INSERM, CNRS, Université d'Angers, Université de Nantes, Nantes, France
| | - Oumeya Adjali
- INSERM UMR 1089, Université de Nantes, CHU de Nantes, Nantes, France
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6
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Hassert M, Brien JD, Pinto AK. Mouse Models of Heterologous Flavivirus Immunity: A Role for Cross-Reactive T Cells. Front Immunol 2019; 10:1045. [PMID: 31143185 PMCID: PMC6520664 DOI: 10.3389/fimmu.2019.01045] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 04/24/2019] [Indexed: 12/20/2022] Open
Abstract
Most of the world is at risk of being infected with a flavivirus such as dengue virus, West Nile virus, yellow fever virus, Japanese encephalitis virus, tick-borne encephalitis virus, and Zika virus, significantly impacting millions of lives. Importantly, many of these genetically similar viruses co-circulate within the same geographic regions, making it likely for individuals living in areas of high flavivirus endemicity to be infected with multiple flaviviruses during their lifetime. Following a flavivirus infection, a robust virus-specific T cell response is generated and the memory recall of this response has been demonstrated to provide long-lasting immunity, protecting against reinfection with the same pathogen. However, multiple studies have shown that this flavivirus specific T cell response can be cross-reactive and active during heterologous flavivirus infection, leading to the question: How does immunity to one flavivirus shape immunity to the next, and how does this impact disease? It has been proposed that in some cases unfavorable disease outcomes may be caused by lower avidity cross-reactive memory T cells generated during a primary flavivirus infection that preferentially expand during a secondary heterologous infection and function sub optimally against the new pathogen. While in other cases, these cross-reactive cells still have the potential to facilitate cross-protection. In this review, we focus on cross-reactive T cell responses to flaviviruses and the concepts and consequences of T cell cross-reactivity, with particular emphasis linking data generated using murine models to our new understanding of disease outcomes following heterologous flavivirus infection.
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Affiliation(s)
- Mariah Hassert
- Department of Molecular Microbiology and Immunology, Saint Louis University, St. Louis, MO, United States
| | - James D Brien
- Department of Molecular Microbiology and Immunology, Saint Louis University, St. Louis, MO, United States
| | - Amelia K Pinto
- Department of Molecular Microbiology and Immunology, Saint Louis University, St. Louis, MO, United States
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7
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Yang J, Jing L, James EA, Gebe JA, Koelle DM, Kwok WW. A Novel Approach of Identifying Immunodominant Self and Viral Antigen Cross-Reactive T Cells and Defining the Epitopes They Recognize. Front Immunol 2018; 9:2811. [PMID: 30619245 PMCID: PMC6298415 DOI: 10.3389/fimmu.2018.02811] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Accepted: 11/14/2018] [Indexed: 11/13/2022] Open
Abstract
Infection and vaccination can lead to activation of autoreactive T cells, including the activation of cross-reactive T cells. However, detecting these cross-reactive T cells and identifying the non-self and self-antigen epitopes is difficult. The current study demonstrates the utility of a novel approach that effectively accomplishes both. We utilized surface expression of CD38 on newly activated CD4 memory T cells as a strategy to identify type 1 diabetes associated autoreactive T cells activated by influenza vaccination in healthy subjects. We identified an influenza A matrix protein (MP) specific CD4+ T cell clone that cross-recognizes an immunodominant epitope from Glutamic Acid Decarboxylase 65 (GAD65) protein. The sequences of the MP and GAD65 peptides are rather distinct, with only 2 identical amino acids within the HLA-DR binding region. This result suggests that activation of autoreactive T cells by microbial infection under certain physiological conditions can occur amongst peptides with minimum amino acid sequence homology. This novel strategy also provides a new research pathway in which to examine activation of autoreactive CD4+ T cells after vaccination or natural infection.
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Affiliation(s)
- Junbao Yang
- Benaroya Research Institute at Virginia Mason, Seattle, WA, United States
| | - Lichen Jing
- Department of Medicine, University of Washington, Seattle, WA, United States
| | - Eddie A James
- Benaroya Research Institute at Virginia Mason, Seattle, WA, United States
| | - John A Gebe
- Benaroya Research Institute at Virginia Mason, Seattle, WA, United States
| | - David M Koelle
- Benaroya Research Institute at Virginia Mason, Seattle, WA, United States.,Department of Medicine, University of Washington, Seattle, WA, United States.,Vaccine and Infectious Diseases Division, Fred Hutchinson Cancer Research Center, Seattle, WA, United States
| | - William W Kwok
- Benaroya Research Institute at Virginia Mason, Seattle, WA, United States.,Department of Medicine, University of Washington, Seattle, WA, United States
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8
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Massilamany C, Koenig A, Reddy J, Huber S, Buskiewicz I. Autoimmunity in picornavirus infections. Curr Opin Virol 2015; 16:8-14. [PMID: 26554915 DOI: 10.1016/j.coviro.2015.10.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Revised: 10/14/2015] [Accepted: 10/18/2015] [Indexed: 12/16/2022]
Abstract
Enteroviruses are small, non-enveloped, positive-sense single-strand RNA viruses, and are ubiquitously found throughout the world. These viruses usually cause asymptomatic or mild febrile illnesses, but have a propensity to induce severe diseases including type 1 diabetes and pancreatitis, paralysis and neuroinflammatory disease, myocarditis, or hepatitis. This pathogenicity may result from induction of autoimmunity to organ-specific antigens. While enterovirus-triggered autoimmunity can arise from multiple mechanisms including antigenic mimicry and release of sequestered antigens, the recent demonstration of T cells expressing dual T cell receptors arising as a natural consequence of Theiler's virus infection is the first demonstration of this autoimmune mechanism.
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Affiliation(s)
- Chandirasegaran Massilamany
- School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, NE 68583, USA
| | - Andreas Koenig
- Department of Medicine and University of Vermont, Colchester, VT 05446, USA
| | - Jay Reddy
- School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, NE 68583, USA
| | - Sally Huber
- Department of Pathology and Vermont Center for Immunobiology and Infectious Diseases, University of Vermont, Colchester, VT 05446, USA
| | - Iwona Buskiewicz
- Department of Pathology and Vermont Center for Immunobiology and Infectious Diseases, University of Vermont, Colchester, VT 05446, USA.
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9
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Lythe G, Callard RE, Hoare RL, Molina-París C. How many TCR clonotypes does a body maintain? J Theor Biol 2015; 389:214-24. [PMID: 26546971 PMCID: PMC4678146 DOI: 10.1016/j.jtbi.2015.10.016] [Citation(s) in RCA: 87] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2015] [Revised: 09/13/2015] [Accepted: 10/07/2015] [Indexed: 01/08/2023]
Abstract
We consider the lifetime of a T cell clonotype, the set of T cells with the same T cell receptor, from its thymic origin to its extinction in a multiclonal repertoire. Using published estimates of total cell numbers and thymic production rates, we calculate the mean number of cells per TCR clonotype, and the total number of clonotypes, in mice and humans. When there is little peripheral division, as in a mouse, the number of cells per clonotype is small and governed by the number of cells with identical TCR that exit the thymus. In humans, peripheral division is important and a clonotype may survive for decades, during which it expands to comprise many cells. We therefore devise and analyse a computational model of homeostasis of a multiclonal population. Each T cell in the model competes for self pMHC stimuli, cells of any one clonotype only recognising a small fraction of the many subsets of stimuli. A constant mean total number of cells is maintained by a balance between cell division and death, and a stable number of clonotypes by a balance between thymic production of new clonotypes and extinction of existing ones. The number of distinct clonotypes in a human body may be smaller than the total number of naive T cells by only one order of magnitude. The number of T cells of one clonotype is an integer. The history of a clonotype starts with release from the thymus, and ends with extinction. Competition and cross-reactivity are included in a natural way. The average number of cells per clonotype, in a human body, is only of order 10.
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Affiliation(s)
- Grant Lythe
- Department of Applied Mathematics, School of Mathematics, University of Leeds, Leeds LS2 9JT, UK.
| | - Robin E Callard
- Institute for Child Health, University College London, 30 Guilford Street, London WC1N 1EH, UK; Centre for Mathematics and Physics in the Life Sciences and Experimental Biology, University College London, Gower Street, London WC1N 1EH, UK
| | - Rollo L Hoare
- Institute for Child Health, University College London, 30 Guilford Street, London WC1N 1EH, UK; Centre for Mathematics and Physics in the Life Sciences and Experimental Biology, University College London, Gower Street, London WC1N 1EH, UK
| | - Carmen Molina-París
- Department of Applied Mathematics, School of Mathematics, University of Leeds, Leeds LS2 9JT, UK
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10
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Sauer EL, Cloake NC, Greer JM. Taming the TCR: antigen-specific immunotherapeutic agents for autoimmune diseases. Int Rev Immunol 2015; 34:460-85. [PMID: 25970132 DOI: 10.3109/08830185.2015.1027822] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Current treatments for autoimmune diseases are typically non-specific anti-inflammatory agents that affect not only the autoreactive cells but also the parts of the immune system that are required to maintain health. There is a need for the development of antigen-specific therapeutic agents that can effectively prevent the autoimmune attack while leaving the rest of the immune system functioning as normal. The simplest way to achieve this is using the autoantigen itself as a tolerizing agent; however, there is some risk involved with administering a potentially pathogenic antigen. In this review, we focus instead on the development and use of modified T cell receptor (TCR) ligands, in which the peptide ligand is modified to change the response by the T cell from a disease inducing to a protective response, and still retain the antigen-specificity necessary to target the autoreactive T cells. We review the use of modified TCR ligands as therapeutic agents in animal models of autoimmunity and in human autoimmune disease, and finally consider how they need to be improved in order to use them effectively in patients with autoimmune disease.
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Affiliation(s)
- Evan L Sauer
- a UQ Centre for Clinical Research , The University of Queensland , Brisbane , Queensland , Australia
| | - Nancy C Cloake
- a UQ Centre for Clinical Research , The University of Queensland , Brisbane , Queensland , Australia
| | - Judith M Greer
- a UQ Centre for Clinical Research , The University of Queensland , Brisbane , Queensland , Australia
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11
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Cavallo F, Aurisicchio L, Mancini R, Ciliberto G. Xenogene vaccination in the therapy of cancer. Expert Opin Biol Ther 2014; 14:1427-42. [DOI: 10.1517/14712598.2014.927433] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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12
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Birnbaum ME, Mendoza JL, Sethi DK, Dong S, Glanville J, Dobbins J, Özkan E, Davis MM, Wucherpfennig KW, Garcia KC. Deconstructing the peptide-MHC specificity of T cell recognition. Cell 2014; 157:1073-87. [PMID: 24855945 PMCID: PMC4071348 DOI: 10.1016/j.cell.2014.03.047] [Citation(s) in RCA: 398] [Impact Index Per Article: 39.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Revised: 02/17/2014] [Accepted: 03/14/2014] [Indexed: 01/07/2023]
Abstract
In order to survey a universe of major histocompatibility complex (MHC)-presented peptide antigens whose numbers greatly exceed the diversity of the T cell repertoire, T cell receptors (TCRs) are thought to be cross-reactive. However, the nature and extent of TCR cross-reactivity has not been conclusively measured experimentally. We developed a system to identify MHC-presented peptide ligands by combining TCR selection of highly diverse yeast-displayed peptide-MHC libraries with deep sequencing. Although we identified hundreds of peptides reactive with each of five different mouse and human TCRs, the selected peptides possessed TCR recognition motifs that bore a close resemblance to their known antigens. This structural conservation of the TCR interaction surface allowed us to exploit deep-sequencing information to computationally identify activating microbial and self-ligands for human autoimmune TCRs. The mechanistic basis of TCR cross-reactivity described here enables effective surveillance of diverse self and foreign antigens without necessitating degenerate recognition of nonhomologous peptides.
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Affiliation(s)
- Michael E. Birnbaum
- Departments of Molecular and Cellular Physiology and Structural Biology, Stanford University School of Medicine, Stanford University, Stanford, CA 94305,Program in Immunology, Stanford University School of Medicine, Stanford University, Stanford, CA 94305
| | - Juan L. Mendoza
- Departments of Molecular and Cellular Physiology and Structural Biology, Stanford University School of Medicine, Stanford University, Stanford, CA 94305
| | - Dhruv K. Sethi
- Department of Cancer Immunology & AIDS, Dana-Farber Cancer Institute, Boston, MA 02115
| | - Shen Dong
- Departments of Molecular and Cellular Physiology and Structural Biology, Stanford University School of Medicine, Stanford University, Stanford, CA 94305
| | - Jacob Glanville
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford University, Stanford, CA 94305,Program in Immunology, Stanford University School of Medicine, Stanford University, Stanford, CA 94305
| | - Jessica Dobbins
- Department of Cancer Immunology & AIDS, Dana-Farber Cancer Institute, Boston, MA 02115,Program in Immunology, Harvard Medical School, Boston, MA 02115
| | - Engin Özkan
- Departments of Molecular and Cellular Physiology and Structural Biology, Stanford University School of Medicine, Stanford University, Stanford, CA 94305,The Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA 94305
| | - Mark M. Davis
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford University, Stanford, CA 94305,Program in Immunology, Stanford University School of Medicine, Stanford University, Stanford, CA 94305,The Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA 94305
| | - Kai W. Wucherpfennig
- Department of Cancer Immunology & AIDS, Dana-Farber Cancer Institute, Boston, MA 02115,Program in Immunology, Harvard Medical School, Boston, MA 02115
| | - K. Christopher Garcia
- Departments of Molecular and Cellular Physiology and Structural Biology, Stanford University School of Medicine, Stanford University, Stanford, CA 94305,Program in Immunology, Stanford University School of Medicine, Stanford University, Stanford, CA 94305,The Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA 94305
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13
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Abstract
αβ T cells are an integral part of protective immunity against pathogens. After precursor cells arise in the adult bone marrow or fetal liver, they migrate to the thymus where they rearrange their T-cell receptor genes (TCR) and undergo selection on the basis of their interactions with ligands expressed by thymic stroma and other cells. Those that survive then exit the thymus to populate the peripheral immune compartment, where they patrol the blood and lymphoid systems. The composition of this pre-immune peripheral repertoire is critically important in determining the robustness of an immune response. In both mice and humans, the magnitude and diversity of a response are directly correlated with the frequency of precursor T cells. Equally relevant are the functional characteristics of these lymphocytes. Engagement of a specific antigen to the TCR activates signaling pathways in the naive T cell that result in cellular proliferation and the acquisition of particular effector functions. A portion of these persist following the resolution of infection and become memory cells. These memory cells can mount a faster and stronger response when they encounter the same antigen at a later time. As the molecular basis for TCR ligand interaction has become better defined, it is clear that some T cells can recognize multiple distinct ligands and therefore T-cell memory developed by exposure to one ligand may play a significant role in the response to a different antigen. Thus, there is an increasing focus on understanding how exposure to related or unrelated antigens influences the T-cell repertoire and impacts subsequent immunity. In this review, we discuss the issue of TCR cross-reactivity in the development of memory phenotype CD4(+) T cells and the implications for pathogen-specific responses. We review both the human and mouse data and discuss the therapeutic implications of these findings in the contexts of infection and vaccination.
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Affiliation(s)
- Laura F Su
- The Division of Immunology and Rheumatology, Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
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14
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Nikoopour E, Cheung R, Bellemore S, Krougly O, Lee-Chan E, Stridsberg M, Singh B. Vasostatin-1 antigenic epitope mapping for induction of cellular and humoral immune responses to chromogranin A autoantigen in NOD mice. Eur J Immunol 2014; 44:1170-80. [DOI: 10.1002/eji.201343986] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Revised: 11/08/2013] [Accepted: 12/18/2013] [Indexed: 11/06/2022]
Affiliation(s)
- Enayat Nikoopour
- Department of Microbiology and Immunology and Centre for Human Immunology; Robarts Research Institute; University of Western Ontario; London Ontario Canada
| | - Rebecca Cheung
- Department of Microbiology and Immunology and Centre for Human Immunology; Robarts Research Institute; University of Western Ontario; London Ontario Canada
| | - Stacey Bellemore
- Department of Microbiology and Immunology and Centre for Human Immunology; Robarts Research Institute; University of Western Ontario; London Ontario Canada
| | - Olga Krougly
- Department of Microbiology and Immunology and Centre for Human Immunology; Robarts Research Institute; University of Western Ontario; London Ontario Canada
| | - Edwin Lee-Chan
- Department of Microbiology and Immunology and Centre for Human Immunology; Robarts Research Institute; University of Western Ontario; London Ontario Canada
| | - Mats Stridsberg
- Department of Medical Sciences; Uppsala University; Uppsala Sweden
| | - Bhagirath Singh
- Department of Microbiology and Immunology and Centre for Human Immunology; Robarts Research Institute; University of Western Ontario; London Ontario Canada
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15
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van den Berg HA, Ladell K, Miners K, Laugel B, Llewellyn-Lacey S, Clement M, Cole DK, Gostick E, Wooldridge L, Sewell AK, Bridgeman JS, Price DA. Cellular-level versus receptor-level response threshold hierarchies in T-cell activation. Front Immunol 2013; 4:250. [PMID: 24046768 PMCID: PMC3763380 DOI: 10.3389/fimmu.2013.00250] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Accepted: 08/09/2013] [Indexed: 12/02/2022] Open
Abstract
Peptide-MHC (pMHC) ligand engagement by T-cell receptors (TCRs) elicits a variety of cellular responses, some of which require substantially more TCR-mediated stimulation than others. This threshold hierarchy could reside at the receptor level, where different response pathways branch off at different stages of the TCR/CD3 triggering cascade, or at the cellular level, where the cumulative TCR signal registered by the T-cell is compared to different threshold values. Alternatively, dual-level thresholds could exist. In this study, we show that the cellular hypothesis provides the most parsimonious explanation consistent with data obtained from an in-depth analysis of distinct functional responses elicited in a clonal T-cell system by a spectrum of biophysically defined altered peptide ligands across a range of concentrations. Further, we derive a mathematical model that describes how ligand density, affinity, and off-rate all affect signaling in distinct ways. However, under the kinetic regime prevailing in the experiments reported here, the TCR/pMHC class I (pMHCI) dissociation rate was found to be the main governing factor. The CD8 coreceptor modulated the TCR/pMHCI interaction and altered peptide ligand potency. Collectively, these findings elucidate the relationship between TCR/pMHCI kinetics and cellular function, thereby providing an integrated mechanistic understanding of T-cell response profiles.
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16
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Eckle SBG, Rossjohn J, McCluskey J. Alloreactivity. Methods Mol Biol 2013; 1034:3-39. [PMID: 23775729 DOI: 10.1007/978-1-62703-493-7_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
Abstract
The alloimmune response between individuals genetically disparate for antigens encoded within the major histocompatibility complex (MHC) remains a substantial barrier to transplantation of solid organs, tissues, and hematopoietic stem cells. Alloreactivity has been an immunological paradox because of its apparent contradiction to the requirement of MHC restriction for the induction of normal T lymphocyte mediated immune responses. Through crystallographic analyses and experimental systems utilizing murine CD8(+) cytolytic T cell clones, major advances have been achieved in understanding the molecular and structural basis of T cell receptor recognition of MHC-peptide complexes and the basis of T cell mediated alloreactivity. These studies have further provided an explanation for the relatively high frequencies of alloreactive T cells compared to the frequencies of T cells for microbial derived antigens.
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Affiliation(s)
- Sidonia B G Eckle
- Department of Microbiology & Immunology, University of Melbourne, Parkville, VIC, Australia
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17
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Garbi N, Kreutzberg T. Dendritic cells enhance the antigen sensitivity of T cells. Front Immunol 2012; 3:389. [PMID: 23272004 PMCID: PMC3530030 DOI: 10.3389/fimmu.2012.00389] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2012] [Accepted: 12/04/2012] [Indexed: 11/13/2022] Open
Abstract
Naive T cells continuously migrate between the circulatory system and lymphoid organs, where they make dynamic contacts with rare dendritic cells (DCs) that strategically form an extensive dendrite network. In such a scenario, T cells spend most of their time quickly scanning the antigenic content of multiple DCs. These interactions provide the basis for efficient adaptive responses by increasing the probability of encounters between rare antigen-specific T cells and those DCs presenting the respective cognate antigens. In the absence of foreign antigen, however, T cells show different degrees of functional sensitivity toward TCR stimulation. Scanning of MHC/self-peptide complexes by naive T cells in the absence of infection is not without consequences but it increases their subsequent response toward antigenic challenge. This indicates that TCR sensitivity in naive T cells is tuned depending on the MHC/self-peptide signals they integrate from the environment even before T cells encounter cognate antigen. DCs have emerged as key components in providing MHC/self-peptide complexes and increasing the sensitivity of T cells toward subsequent TCR triggering. In the absence of cognate antigen, DCs maintain a tonic TCR signaling and license T cells for immune synapse (IS) maturation resulting in enhanced T cell responses toward a subsequent antigen stimulation. This review discusses recent findings on this subject and highlights the importance of the DC pool size for optimal T cell awareness to foreign antigen.
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Affiliation(s)
- Natalio Garbi
- Department of Molecular Immunology, Institutes of Molecular Medicine and Experimental Immunology, University of Bonn Bonn, Germany
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18
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Klinke DJ, Cheng N, Chambers E. Quantifying crosstalk among interferon-γ, interleukin-12, and tumor necrosis factor signaling pathways within a TH1 cell model. Sci Signal 2012; 5:ra32. [PMID: 22510470 DOI: 10.1126/scisignal.2002657] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
T helper (T(H)) cells integrate biochemical cues present in the tissue microenvironment and produce cytokines that orchestrate immune responses. Previous discoveries have revealed a qualitative understanding of how T(H) cells process this biochemical information; however, the lack of methods to quantify how well these depictions apply to a particular cell type limits our ability to translate our knowledge of the immune response from one biological system to another. We used model-based inference methods and quantitative flow cytometric analysis in mouse T(H)1 cells to determine the relative contributions of different putative branches in the signaling network that responds to the cytokine interleukin-12 (IL-12), which links innate and adaptive immunity. The response of T(H)1 cells to IL-12 exhibited hysteresis because it depended on both current and past exposure and engaged a positive feedback mechanism through the direct activation of signal transducer and activator of transcription 1. The hysteresis in the dose-response curve to IL-12 created a transient "memory" by sustaining cytokine secretion after the withdrawal of the stimulus. In summary, this combined experimental and computational approach illustrates how model-based inference can be used to better understand how cells process and act upon biochemical cues present in the tissue microenvironment.
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Affiliation(s)
- David J Klinke
- Department of Chemical Engineering, West Virginia University, Post Office Box 6102, Morgantown, WV 26506, USA.
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19
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Wooldridge L, Ekeruche-Makinde J, van den Berg HA, Skowera A, Miles JJ, Tan MP, Dolton G, Clement M, Llewellyn-Lacey S, Price DA, Peakman M, Sewell AK. A single autoimmune T cell receptor recognizes more than a million different peptides. J Biol Chem 2011; 287:1168-77. [PMID: 22102287 PMCID: PMC3256900 DOI: 10.1074/jbc.m111.289488] [Citation(s) in RCA: 307] [Impact Index Per Article: 23.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The T cell receptor (TCR) orchestrates immune responses by binding to foreign peptides presented at the cell surface in the context of major histocompatibility complex (MHC) molecules. Effective immunity requires that all possible foreign peptide-MHC molecules are recognized or risks leaving holes in immune coverage that pathogens could quickly evolve to exploit. It is unclear how a limited pool of <10(8) human TCRs can successfully provide immunity to the vast array of possible different peptides that could be produced from 20 proteogenic amino acids and presented by self-MHC molecules (>10(15) distinct peptide-MHCs). One possibility is that T cell immunity incorporates an extremely high level of receptor degeneracy, enabling each TCR to recognize multiple peptides. However, the extent of such TCR degeneracy has never been fully quantified. Here, we perform a comprehensive experimental and mathematical analysis to reveal that a single patient-derived autoimmune CD8(+) T cell clone of pathogenic relevance in human type I diabetes recognizes >one million distinct decamer peptides in the context of a single MHC class I molecule. A large number of peptides that acted as substantially better agonists than the wild-type "index" preproinsulin-derived peptide (ALWGPDPAAA) were identified. The RQFGPDFPTI peptide (sampled from >10(8) peptides) was >100-fold more potent than the index peptide despite differing from this sequence at 7 of 10 positions. Quantification of this previously unappreciated high level of CD8(+) T cell cross-reactivity represents an important step toward understanding the system requirements for adaptive immunity and highlights the enormous potential of TCR degeneracy to be the causative factor in autoimmune disease.
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Affiliation(s)
- Linda Wooldridge
- Institute of Infection and Immunity, Cardiff University School of Medicine, Henry Wellcome Building, Heath Park, Cardiff CF14 4XN, United Kingdom
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20
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Wucherpfennig KW, Sethi D. T cell receptor recognition of self and foreign antigens in the induction of autoimmunity. Semin Immunol 2011; 23:84-91. [PMID: 21306912 DOI: 10.1016/j.smim.2011.01.007] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2010] [Accepted: 01/10/2011] [Indexed: 10/18/2022]
Abstract
The major histocompatibility complex (MHC) on human chromosome 6 represents the most important genetic locus for a number of common human autoimmune diseases. Specific alleles that differ from closely related alleles by only one or a few amino acids in the peptide binding groove are frequently strongly associated with disease susceptibility, raising the important question of which peptide presentation events are critical in disease initiation and progression. This review will cover a number of topics pertinent to this fundamental question, including MHC linked disease susceptibility to autoimmune diseases, molecular mechanisms for the role of MHC molecules in autoimmune diseases as well as the recognition of self and microbial peptides by self-reactive T cell receptors (TCRs).
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Affiliation(s)
- Kai W Wucherpfennig
- Department of Cancer Immunology & AIDS, Dana-Farber Cancer Institute, Boston, MA 02115, USA.
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21
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McLean-Tooke A, Barge D, Spickett GP, Gennery AR. Flow Cytometric Analysis of TCR Vβ Repertoire in Patients with 22q11.2 Deletion Syndrome. Scand J Immunol 2011; 73:577-85. [DOI: 10.1111/j.1365-3083.2011.02527.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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22
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Duvvuri VRSK, Moghadas SM, Guo H, Duvvuri B, Heffernan JM, Fisman DN, Wu GE, Wu J. Highly conserved cross-reactive CD4+ T-cell HA-epitopes of seasonal and the 2009 pandemic influenza viruses. Influenza Other Respir Viruses 2010; 4:249-58. [PMID: 20716156 PMCID: PMC4634651 DOI: 10.1111/j.1750-2659.2010.00161.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Please cite this paper as: Duvvuri et al. (2010) Highly conserved cross‐reactive CD4+ T‐cell HA‐epitopes of seasonal and the 2009 pandemic influenza viruses. Influenza and Other Respiratory Viruses 4(5), 249–258. Background The relatively mild nature of the 2009 influenza pandemic (nH1N1) highlights the overriding importance of pre‐existing immune memory. The absence of cross‐reactive antibodies to nH1N1 in most individuals suggests that such attenuation may be attributed to pre‐existing cellular immune responses to epitopes shared between nH1N1 virus and previously circulating strains of inter‐pandemic influenza A viruses. Results We sought to identify potential CD4+ T cell epitopes and predict the level of cross‐reactivity of responding T cells. By performing large‐scale major histocompatibility complex II analyses on Hemagglutinin (HA) proteins, we investigated the degree of T‐cell cross‐reactivity between seasonal influenza A (sH1N1, H3N2) from 1968 to 2009 and nH1N1 strains. Each epitope was examined against all the protein sequences that correspond to sH1N1, H3N2, and nH1N1. T‐cell cross‐reactivity was estimated to be 52%, and maximum conservancy was found between sH1N1 and nH1N1 with a significant correlation (P < 0·05). Conclusions Given the importance of cellular responses in kinetics of influenza infection in humans, our findings underscore the role of T‐cell assays for understanding the inter‐pandemic variability in severity and for planning treatment methods for emerging influenza viruses.
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Affiliation(s)
- Venkata R S K Duvvuri
- MITACS Centre for Disease Modeling, York Institute of Health Research, Toronto, Ontario, Canada
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23
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Jenkins MK, Chu HH, McLachlan JB, Moon JJ. On the composition of the preimmune repertoire of T cells specific for Peptide-major histocompatibility complex ligands. Annu Rev Immunol 2010; 28:275-94. [PMID: 20307209 DOI: 10.1146/annurev-immunol-030409-101253] [Citation(s) in RCA: 172] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Millions of T cells are produced in the thymus, each expressing a unique alpha/beta T cell receptor (TCR) capable of binding to a foreign peptide in the binding groove of a host major histocompatibility complex (MHC) molecule. T cell-mediated immunity to infection is due to the proliferation and differentiation of rare clones in the preimmune repertoire that by chance express TCRs specific for peptide-MHC (pMHC) ligands derived from the microorganism. Here we review recent findings that have altered our understanding of how the preimmune repertoire is established. Recent structural studies indicate that a germline-encoded tendency of TCRs to bind MHC molecules contributes to the MHC bias of T cell repertoires. It has also become clear that the preimmune repertoire contains functionally heterogeneous subsets including recent thymic emigrants, mature naive phenotype cells, memory phenotype cells, and natural regulatory T cells. In addition, sensitive new detection methods have revealed that the repertoire of naive phenotype T cells consists of distinct pMHC-specific populations that consistently vary in size in different individuals. The implications of these new findings for the clonal selection theory, self-tolerance, and immunodominance are discussed.
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Affiliation(s)
- Marc K Jenkins
- Department of Microbiology, Center for Immunology, University of Minnesota Medical School, Minneapolis, 55455, USA.
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24
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Huber SA. Autoimmunity in Coxsackievirus B3 induced myocarditis: role of estrogen in suppressing autoimmunity. Future Virol 2010; 5:273-286. [PMID: 20963181 DOI: 10.2217/fvl.10.19] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Picornaviruses are small, non-enveloped, single stranded, positive sense RNA viruses which cause multiple diseases including myocarditis/dilated cardiomyopathy, type 1 diabetes, encephalitis, myositis, orchitis and hepatitis. Although picornaviruses directly kill cells, tissue injury primarily results from autoimmunity to self antigens. Viruses induce autoimmunity by: aborting deletion of self-reactive T cells during T cell ontogeny; reversing anergy of peripheral autoimmune T cells; eliminating T regulatory cells; stimulating self-reactive T cells through antigenic mimicry or cryptic epitopes; and acting as an adjuvant for self molecules released during virus infection. Most autoimmune diseases (SLE, rheumatoid arthritis, Grave's disease) predominate in females, but diseases associated with picornavirus infections predominate in males. T regulatory cells are activated in infected females because of the combined effects of estrogen and innate immunity.
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Affiliation(s)
- SA Huber
- Department of Pathology, University of Vermont, 208 S Park Drive, Colchester, VT 05446, USA
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25
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López de Castro JA. The HLA-B27 peptidome: Building on the cornerstone. ACTA ACUST UNITED AC 2010; 62:316-9. [DOI: 10.1002/art.27188] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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26
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Manipulating antigenic ligand strength to selectively target myelin-reactive CD4+ T cells in EAE. J Neuroimmune Pharmacol 2009; 5:176-88. [PMID: 19904613 DOI: 10.1007/s11481-009-9181-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2009] [Accepted: 10/15/2009] [Indexed: 10/20/2022]
Abstract
The development of antigen-specific therapies for the selective tolerization of autoreactive T cells remains the Holy Grail for the treatment of T-cell-mediated autoimmune diseases such as multiple sclerosis (MS) and its animal model experimental autoimmune encephalomyelitis (EAE). This quest remains elusive, however, as the numerous antigen-specific strategies targeting myelin-specific T cells over the years have failed to result in clinical success. In this review, we revisit the antigen-based therapies used in the treatment of myelin-specific CD4+ T cells in the context of the functional avidity and the strength of signal of the encephalitogenic CD4+ T cell repertoire. In light of differences in activation thresholds, we propose that autoreactive T cells are not all equal, and therefore tolerance induction strategies must incorporate ligand strength in order to be successful in treating EAE and ultimately the human disease MS.
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27
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Abstract
Two main etiological components are considered important in human autoimmune diseases including multiple sclerosis (MS), first the immunogenetic background and second environmental factors. Among the latter, infectious organisms are probably the most relevant, and epidemiological studies in MS firmly support that viral infections often precede disease exacerbations or the onset of MS. Infectious agents can contribute to disease development or phenotypic expression in different ways. Our focus will be directed on molecular mimicry, i.e. antigenic similarity between structural epitopes or peptide sequences from infectious organisms with those found in self proteins of the host. The intriguing concept of molecular mimicry has evolved substantially since its introduction over 20 years ago. We will summarize the most important developments and discuss puzzling questions, which remain open despite many claims that molecular mimicry is involved in the development of human autoimmune disease after infections or vaccinations.
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Affiliation(s)
- Mireia Sospedra
- Unitat de Neuroimmunologia Clinica, Hospital Universitari Vall d'Hebron, Pg. Vall d'Hebron, 119-129, Barcelona, 08035, Spain
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Iero M, Filipazzi P, Castelli C, Belli F, Valdagni R, Parmiani G, Patuzzo R, Santinami M, Rivoltini L. Modified peptides in anti-cancer vaccines: are we eventually improving anti-tumour immunity? Cancer Immunol Immunother 2009; 58:1159-67. [PMID: 18998128 PMCID: PMC11030573 DOI: 10.1007/s00262-008-0610-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2008] [Accepted: 10/03/2008] [Indexed: 12/22/2022]
Abstract
The discovery of tumour antigens recognized by T cells and the features of immune responses directed against them has paved the way to a multitude of clinical studies aimed at boosting anti-tumour T cell immunity as a therapeutic tool for cancer patients. One of the different strategies explored to ameliorate the immunogenicity of tumour antigens in vaccine protocols is represented by the use of optimized peptides or altered peptide ligands, whose amino acid sequence has been modified for improving HLA binding or TCR interaction with respect to native epitopes. However, despite the promising results achieved with preclinical studies, the clinical efficacy of this approach has not yet met the expectations. Although multiple reasons could explain the relative failure of altered peptide ligands as more effective cancer vaccines, the possibility that T cells primed by modified tumour peptides might may be unable to effectively cross-recognize tumour cells has not been sufficiently addressed. Indeed, the introduction of conservative amino acid substitutions may still produce diverse and unpredictable changes in the HLA/peptide interface, with consequent modifications of the TCR repertoire that can interact with the complex. This could lead to the expansion of a broad array of T cells whose TCRs may not necessarily react with equivalent affinity with the original antigenic epitope. Considering the results presently achieved with this vaccine approach, and the emerging availability of alternative strategies for boosting anti-tumour immunity, the use of modified tumour peptides could be reconsidered.
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Affiliation(s)
- Manuela Iero
- Unit of Immunotherapy of Human Tumours, Fondazione IRCCS Istituto Nazionale Tumori, Via Venezian 1, 20133 Milan, Italy
| | - Paola Filipazzi
- Unit of Immunotherapy of Human Tumours, Fondazione IRCCS Istituto Nazionale Tumori, Via Venezian 1, 20133 Milan, Italy
| | - Chiara Castelli
- Unit of Immunotherapy of Human Tumours, Fondazione IRCCS Istituto Nazionale Tumori, Via Venezian 1, 20133 Milan, Italy
| | - Filiberto Belli
- Unit of Colo-rectal Surgery, Fondazione IRCCS Istituto Nazionale Tumori, Milan, Italy
| | - Riccardo Valdagni
- Unit of Prostate Cancer Program, Fondazione IRCCS Istituto Nazionale Tumori, Milan, Italy
| | - Giorgio Parmiani
- Unit of Immunobiotherapy of Solid Tumours, San Raffaele Scientific Institute, Milan, Italy
| | - Roberto Patuzzo
- Unit of Melanoma and Sarcoma Surgery, Fondazione IRCCS Istituto Nazionale Tumori, Milan, Italy
| | - Mario Santinami
- Unit of Melanoma and Sarcoma Surgery, Fondazione IRCCS Istituto Nazionale Tumori, Milan, Italy
| | - Licia Rivoltini
- Unit of Immunotherapy of Human Tumours, Fondazione IRCCS Istituto Nazionale Tumori, Via Venezian 1, 20133 Milan, Italy
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29
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Cragnolini JJ, García-Medel N, de Castro JAL. Endogenous processing and presentation of T-cell epitopes from Chlamydia trachomatis with relevance in HLA-B27-associated reactive arthritis. Mol Cell Proteomics 2009; 8:1850-9. [PMID: 19443418 DOI: 10.1074/mcp.m900107-mcp200] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Chlamydia trachomatis triggers reactive arthritis, a spondyloarthropathy linked to the human major histocompatibility complex molecule HLA-B27, through an unknown mechanism that might involve molecular mimicry between chlamydial and self-derived HLA-B27 ligands. Chlamydia-specific CD8(+) T-cells are found in reactive arthritis patients, but the immunogenic epitopes are unknown. A previous screening of the chlamydial genome for putative HLA-B27 ligands predicted multiple peptides that were recognized in vitro by CD8(+) T-lymphocytes from patients. Here stable transfectants expressing bacterial fusion proteins in human cells were generated to investigate the endogenous processing and presentation by HLA-B27 of two such epitopes through comparative immunoproteomics of HLA-B27-bound peptide repertoires. A predicted T-cell epitope, from the CT610 gene product, was presented by HLA-B27. This is, to our knowledge, the first endogenously processed epitope involved in HLA-B27-restricted responses against C. trachomatis in reactive arthritis. A second predicted epitope, from the CT634 gene product, was not detected. Instead a non-predicted nonamer from the same protein was identified. Both bacterial peptides showed very high homology with human sequences containing the HLA-B27 binding motif. Thus, expression and intracellular processing of chlamydial proteins into human cells allowed us to identify two bacterial HLA-B27 ligands, including the first endogenous T-cell epitope from C. trachomatis involved in spondyloarthropathy. That human proteins contain sequences mimicking chlamydial T-cell epitopes suggests a basis for an autoimmune component of Chlamydia-induced HLA-B27-associated disease.
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Affiliation(s)
- Juan J Cragnolini
- Centro de Biología Molecular Severo Ochoa (Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid), Universidad Autónoma, 28049 Madrid, Spain
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30
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Armstrong K, Piepenbrink K, Baker B. Conformational changes and flexibility in T-cell receptor recognition of peptide-MHC complexes. Biochem J 2008; 415:183-96. [PMID: 18800968 PMCID: PMC2782316 DOI: 10.1042/bj20080850] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2008] [Revised: 06/23/2008] [Accepted: 07/09/2008] [Indexed: 01/07/2023]
Abstract
A necessary feature of the immune system, TCR (T-cell receptor) cross-reactivity has been implicated in numerous autoimmune pathologies and is an underlying cause of transplant rejection. Early studies of the interactions of alphabeta TCRs (T-cell receptors) with their peptide-MHC ligands suggested that conformational plasticity in the TCR CDR (complementarity determining region) loops is a dominant contributor to T-cell cross-reactivity. Since these initial studies, the database of TCRs whose structures have been solved both bound and free is now large enough to permit general conclusions to be drawn about the extent of TCR plasticity and the types and locations of motion that occur. In the present paper, we review the conformational differences between free and bound TCRs, quantifying the structural changes that occur and discussing their possible roles in specificity and cross-reactivity. We show that, rather than undergoing major structural alterations or 'folding' upon binding, the majority of TCR CDR loops shift by relatively small amounts. The structural changes that do occur are dominated by hinge-bending motions, with loop remodelling usually occurring near loop apexes. As predicted from previous studies, the largest changes are in the hypervariable CDR3alpha and CDR3beta loops, although in some cases the germline-encoded CDR1alpha and CDR2alpha loops shift in magnitudes that approximate those of the CDR3 loops. Intriguingly, the smallest shifts are in the germline-encoded loops of the beta-chain, consistent with recent suggestions that the TCR beta domain may drive ligand recognition.
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Affiliation(s)
- Kathryn M. Armstrong
- *Department of Chemistry and Biochemistry, 251 Nieuwland Science Hall, University of Notre Dame, Notre Dame, IN 46556, U.S.A
| | - Kurt H. Piepenbrink
- *Department of Chemistry and Biochemistry, 251 Nieuwland Science Hall, University of Notre Dame, Notre Dame, IN 46556, U.S.A
| | - Brian M. Baker
- *Department of Chemistry and Biochemistry, 251 Nieuwland Science Hall, University of Notre Dame, Notre Dame, IN 46556, U.S.A
- †Walther Cancer Research Center, 251 Nieuwland Science Hall, University of Notre Dame, Notre Dame, IN 46556, U.S.A
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31
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Armstrong KM, Insaidoo FK, Baker BM. Thermodynamics of T-cell receptor-peptide/MHC interactions: progress and opportunities. J Mol Recognit 2008; 21:275-87. [PMID: 18496839 DOI: 10.1002/jmr.896] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
alphabeta T-cell receptors (TCRs) recognize peptide antigens presented by class I or class II major histocompatibility complex molecules (pMHC). Here we review the use of thermodynamic measurements in the study of TCR-pMHC interactions, with attention to the diversity in binding thermodynamics and how this is related to the variation in TCR-pMHC interfaces. We show that there is no enthalpic or entropic signature for TCR binding; rather, enthalpy and entropy changes vary in a compensatory manner that reflects a narrow free energy window for the interactions that have been characterized. Binding enthalpy and entropy changes do not correlate with structural features such as buried surface area or the number of hydrogen bonds within TCR-pMHC interfaces, possibly reflecting the myriad of contributors to binding thermodynamics, but likely also reflecting a reliance on van't Hoff over calorimetric measurements and the unaccounted influence of equilibria linked to binding. TCR-pMHC binding heat capacity changes likewise vary considerably. In some cases, the heat capacity changes are consistent with conformational differences between bound and free receptors, but there is little data indicating these conformational differences represent the need to organize disordered CDR loops. In this regard, we discuss how thermodynamics may provide additional insight into conformational changes occurring upon TCR binding. Finally, we highlight opportunities for the further use of thermodynamic measurements in the study of TCR-pMHC interactions, not only for understanding TCR binding in general, but also for understanding specifics of individual interactions and the engineering of TCRs with desired molecular recognition properties.
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Affiliation(s)
- Kathryn M Armstrong
- Department of Chemistry and Biochemistry, University of Notre Dame, 251 Nieuwland Science Hall, Notre Dame, IN 46556, USA
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32
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Chidgey AR, Boyd RL. Thymic stromal cells and positive selection. APMIS 2008. [DOI: 10.1111/j.1600-0463.2001.907801.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Voelter V, Rufer N, Reynard S, Greub G, Brookes R, Guillaume P, Grosjean F, Fagerberg T, Michelin O, Rowland-Jones S, Pinilla C, Leyvraz S, Romero P, Appay V. Characterization of Melan-A reactive memory CD8+ T cells in a healthy donor. Int Immunol 2008; 20:1087-96. [DOI: 10.1093/intimm/dxn066] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Abstract
Virus infections are implicated in several autoimmune diseases. Multiple mechanisms of autoimmunity induction have been proposed including antigenic mimicry, production of cryptic epitopes and infection acting as both adjuvant for self-antigens and the mechanism of releasing these cell antigens. Evidence for these mechanisms in coxsackievirus B3 induced myocarditis is discussed.
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Affiliation(s)
- Sally A Huber
- University of Vermont, Department of Pathology, Colchester, VT 05446, USA.
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Ryan KR, Patel SD, Stephens LA, Anderton SM. Death, adaptation and regulation: The three pillars of immune tolerance restrict the risk of autoimmune disease caused by molecular mimicry. J Autoimmun 2007; 29:262-71. [PMID: 17870412 DOI: 10.1016/j.jaut.2007.07.014] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Extensive cross-reactivity in T cell receptor (TCR) recognition of peptide-MHC (pMHC) complexes seems to be essential to give sufficient immune surveillance against invading pathogens. This carries with it an inherent risk that T cells activated during a response to clear an infection can, perhaps years later, respond to a self pMHC of sufficient similarity. This lies at the heart of the molecular mimicry theory. Here we discuss our studies on the disease-causing potential of altered peptide ligands (APL) based on the sequence of a single autoantigenic epitope, the Ac1-9 peptide of myelin basic protein that induces experimental autoimmune encephalomyelitis in mice. These show that the window of similarity to self for induction of disease by cross-reactive non-self peptides is actually quite restricted. We show that each of the three pillars of immune tolerance (death, anergy/adaptation and regulation) has a role in limiting the risk of molecular mimicry by maintaining a threshold for harm.
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Affiliation(s)
- Kelli R Ryan
- University of Edinburgh, Institute of Immunology and Infection Research, School of Biological Sciences, Kings Buildings, West Mains Road, Edinburgh, EH9 3JT, UK
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36
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Cragnolini JJ, de Castro JAL. Identification of endogenously presented peptides from Chlamydia trachomatis with high homology to human proteins and to a natural self-ligand of HLA-B27. Mol Cell Proteomics 2007; 7:170-80. [PMID: 17934211 DOI: 10.1074/mcp.m700386-mcp200] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A strategy for the stable expression of proteins, or large protein fragments, from Chlamydia trachomatis into human cells was designed to identify bacterial epitopes endogenously processed and presented by HLA-B27. Fusion protein constructs in which the green fluorescent protein gene was placed at the 5'-end of the bacterial DNA primase gene or some of its fragments were transfected into B*2705-C1R cells. One of these constructs, including residues 90-450 of the bacterial protein, was stably and efficiently expressed. Mass spectrometry-based comparative analysis of HLA-B27-bound peptide pools led to identification of three HLA-B27 ligands differentially presented in the transfectant cells. Sequencing of these peptides confirmed that they were derived from the bacterial DNA primase. One of them, spanning residues 211-221, showed 55% sequence identity with a known self-ligand of HLA-B27 derived from its own molecule. The other two bacterial ligands, P-(112-121) and P-(112-122), were derived from the same region and differed in length by one residue at the C terminus. Both peptides showed >50% identity with multiple human protein sequences that possessed the optimal peptide motifs for HLA-B27 binding. Thus, expression of proteins from arthritogenic bacteria in HLA-B27-positive human cells allows identifying bacterial peptides that are endogenously processed and presented by HLA-B27 and show molecular mimicry with known self-ligands of this molecule and human proteins.
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Affiliation(s)
- Juan J Cragnolini
- Centro de Biología Molecular Severo Ochoa (Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid), Universidad Autónoma, 28049 Madrid, Spain
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Moon JJ, Chu HH, Pepper M, McSorley SJ, Jameson SC, Kedl RM, Jenkins MK. Naive CD4(+) T cell frequency varies for different epitopes and predicts repertoire diversity and response magnitude. Immunity 2007; 27:203-13. [PMID: 17707129 PMCID: PMC2200089 DOI: 10.1016/j.immuni.2007.07.007] [Citation(s) in RCA: 763] [Impact Index Per Article: 44.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2007] [Revised: 06/21/2007] [Accepted: 07/02/2007] [Indexed: 01/21/2023]
Abstract
Cell-mediated immunity stems from the proliferation of naive T lymphocytes expressing T cell antigen receptors (TCRs) specific for foreign peptides bound to host major histocompatibility complex (MHC) molecules. Because of the tremendous diversity of the T cell repertoire, naive T cells specific for any one peptide:MHC complex (pMHC) are extremely rare. Thus, it is not known how many naive T cells of any given pMHC specificity exist in the body or how that number influences the immune response. By using soluble pMHC class II (pMHCII) tetramers and magnetic bead enrichment, we found that three different pMHCII-specific naive CD4(+) T cell populations vary in frequency from 20 to 200 cells per mouse. Moreover, naive population size predicted the size and TCR diversity of the primary CD4(+) T cell response after immunization with relevant peptide. Thus, variation in naive T cell frequencies can explain why some peptides are stronger immunogens than others.
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Affiliation(s)
- James J. Moon
- Department of Microbiology, University of Minnesota Medical School, Minneapolis, MN, 55455
- Center for Immunology, University of Minnesota Medical School, Minneapolis, MN, 55455
| | - H. Hamlet Chu
- Department of Microbiology, University of Minnesota Medical School, Minneapolis, MN, 55455
- Center for Immunology, University of Minnesota Medical School, Minneapolis, MN, 55455
| | - Marion Pepper
- Department of Microbiology, University of Minnesota Medical School, Minneapolis, MN, 55455
- Center for Immunology, University of Minnesota Medical School, Minneapolis, MN, 55455
| | - Stephen J. McSorley
- Department of Medicine, University of Minnesota Medical School, Minneapolis, MN, 55455
- Center for Immunology, University of Minnesota Medical School, Minneapolis, MN, 55455
| | - Stephen C. Jameson
- Laboratory Medicine and Pathology, University of Minnesota Medical School, Minneapolis, MN, 55455
- Center for Immunology, University of Minnesota Medical School, Minneapolis, MN, 55455
| | - Ross M. Kedl
- Integrated Department of Immunology, University of Colorado Health Sciences Center, Denver, CO 80206
| | - Marc K. Jenkins
- Department of Microbiology, University of Minnesota Medical School, Minneapolis, MN, 55455
- Center for Immunology, University of Minnesota Medical School, Minneapolis, MN, 55455
- To whom correspondence should be addressed, e-mail: ; Tel: (612) 626-2175; Fax: 612-625-2199
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38
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Wucherpfennig KW, Allen PM, Celada F, Cohen IR, De Boer R, Garcia KC, Goldstein B, Greenspan R, Hafler D, Hodgkin P, Huseby ES, Krakauer DC, Nemazee D, Perelson AS, Pinilla C, Strong RK, Sercarz EE. Polyspecificity of T cell and B cell receptor recognition. Semin Immunol 2007; 19:216-24. [PMID: 17398114 PMCID: PMC2034306 DOI: 10.1016/j.smim.2007.02.012] [Citation(s) in RCA: 153] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2007] [Accepted: 02/26/2007] [Indexed: 02/06/2023]
Abstract
A recent workshop discussed the recognition of multiple distinct ligands by individual T cell and B cell receptors and the implications of this discovery for lymphocyte biology. The workshop recommends general use of the term polyspecificity because it emphasizes two fundamental aspects, the inherent specificity of receptor recognition and the ability to recognize multiple ligands. Many different examples of polyspecificity and the structural mechanisms were discussed, and the group concluded that polyspecificity is a general, inherent feature of TCR and antibody recognition. This review summarizes the relevance of polyspecificity for lymphocyte development, activation and disease processes.
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Affiliation(s)
- Kai W Wucherpfennig
- Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115, USA.
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Donermeyer DL, Weber KS, Kranz DM, Allen PM. The study of high-affinity TCRs reveals duality in T cell recognition of antigen: specificity and degeneracy. THE JOURNAL OF IMMUNOLOGY 2007; 177:6911-9. [PMID: 17082606 DOI: 10.4049/jimmunol.177.10.6911] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
TCRs exhibit a high degree of Ag specificity, even though their affinity for the peptide/MHC ligand is in the micromolar range. To explore how Ag specificity is achieved, we studied murine T cells expressing high-affinity TCRs engineered by in vitro evolution for binding to hemoglobin peptide/class II complex (Hb/I-Ek). These TCRs were shown previously to maintain Ag specificity, despite having up to 800-fold higher affinity. We compared the response of the high-affinity TCRs and the low-affinity 3.L2 TCR toward a comprehensive set of peptides containing single substitutions at each TCR contact residue. This specificity analysis revealed that the increase in affinity resulted in a dramatic increase in the number of stimulatory peptides. The apparent discrepancy between observed degeneracy in the recognition of single amino acid-substituted Hb peptides and overall Ag specificity of the high-affinity TCRs was examined by generating chimeric peptides between the stimulatory Hb and nonstimulatory moth cytochrome c peptides. These experiments showed that MHC anchor residues significantly affected TCR recognition of peptide. The high-affinity TCRs allowed us to estimate the affinity, in the millimolar range, of immunologically relevant interactions of the TCR with peptide/MHC ligands that were previously unmeasurable because of their weak nature. Thus, through the study of high-affinity TCRs, we demonstrated that a TCR is more tolerant of single TCR contact residue substitutions than other peptide changes, revealing that recognition of Ag by T cells can exhibit both specificity and degeneracy.
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Affiliation(s)
- David L Donermeyer
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA
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40
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Uhlin M, Masucci M, Levitsky V. Is the activity of partially agonistic MHC:peptide ligands dependent on the quality of immunological help? Scand J Immunol 2007; 64:581-7. [PMID: 17083613 DOI: 10.1111/j.1365-3083.2006.01850.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
CD8(+) cytotoxic T lymphocytes (CTL) are important for the immunological control of infections and tumours. Engagement of the T-cell receptor (TCR) with major histocompatibility complex (MHC) class I/peptide complexes on antigen-presenting cells (APC) is the key interaction, which initiates the process of T-cell activation. Depending on the affinity of this interaction, different arrays of signalling pathways and functional outcomes can be activated in the specific T cells. Molecular alterations in the peptide bound to the MHC class I can lead to a lower affinity of the MHC:TCR interaction resulting in incomplete or qualitatively different T-cell responses. Altered peptide ligands (APL) exhibiting such activity are referred to as partial agonists and often occur naturally through genetic instability, which affects T-cell epitopes derived from rapidly mutating viruses or tumour-associated cellular antigens. Partial agonists are usually viewed as peptide variants, which escape efficient CTL recognition. Our recent data suggest that APL can not only trigger incomplete activation but also induce and modulate intrinsic T-cell programmes leading to the shut-off of specific CTL responses. This APL-induced suppression appears to be more prominent in the absence of immunological help, suggesting that under conditions of immune deregulation APL may actively inhibit CTL responses against infectious agents or tumours. In this review, we discuss experimental data supporting this model and possible role of APL-induced immunosuppression in different pathological conditions.
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Affiliation(s)
- M Uhlin
- Department of Microbiology, Tumor and Cell Biology Center and, Karolinska Institutet, Stockholm, Sweden.
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41
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Sospedra M, Martin R. When T cells recognize a pattern, they might cause trouble. Curr Opin Immunol 2006; 18:697-703. [PMID: 17010587 DOI: 10.1016/j.coi.2006.09.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2006] [Accepted: 09/19/2006] [Indexed: 11/29/2022]
Abstract
The mechanisms of self and non-self discrimination by T cells remain a fascinating topic for immunologists. How the immune system achieves protection of the host against an ever-changing realm of pathogens using a rather limited repertoire of T-cell receptors and at the same time avoids inflicting damage against its own tissues is equally puzzling. Although a better understanding of these questions has come from studies of the extent of cross reactivity of T-cell clones specific for foreign or self antigens, and also from examination of the different antigen avidities by which they recognize either type of antigen, many details are still lacking. Recently, there has been investigation into how T cells of the adaptive immune system can recognize functional protein domains or amino acid patterns. This type of T-cell reactivity is reminiscent of the pattern recognition that is firmly established as an important function of innate immune receptors such as Toll-like receptors. Many functional protein domains are conserved in evolution and are shared by a wide spectrum of pathogens, as well as by proteins of animals and humans. Hence, pattern recognition by adaptive immune cells might represent an efficient mechanism for host protection by the above-mentioned limited number of T-cell receptors. However, the fact that such functional domains occur so frequently in nature also implies that pattern recognition by T cells might cause autoimmunity, and recent data support this hypothesis.
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Affiliation(s)
- Mireia Sospedra
- Institucio Catalana de Recerca i Estudis Avançats (ICREA), Institut de Recerca, Unitat de Neuroimmunologia Clinica, Hospital Universitari Vall D'Hebron, Passeig Vall D'Hebron 119-129, Barcelona, Spain
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42
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van den Boorn JG, Le Poole IC, Luiten RM. T-cell avidity and tuning: the flexible connection between tolerance and autoimmunity. Int Rev Immunol 2006; 25:235-58. [PMID: 16818373 PMCID: PMC3462655 DOI: 10.1080/08830180600743081] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Thymic T-cell selection mechanisms generate a cross-reactive, self-MHC restricted peripheral T-cell pool. Affinity and avidity are of profound influence on this selection and the generation of immunity. Autoreactive T cells can escape thymic deletion by lowering their avidity and retain this "tuned" state in the periphery. Upon activation, tuned T cells can cause autoimmunity, while immunotherapeutic strategies may be hampered by existing T-cell tolerance. The regulation of T-cell avidity and tuning therefore determines the balance between tolerance and autoimmunity and should be taken into account in the design of therapeutic strategies aimed at T-cell reactivity.
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Affiliation(s)
- Jasper G van den Boorn
- Netherlands Institute for Pigment Disorders and Department of Dermatology, AMC, University of Amsterdam, Amsterdam, The Netherlands.
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43
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Gómez P, Montserrat V, Marcilla M, Paradela A, de Castro JAL. B*2707 differs in peptide specificity from B*2705 and B*2704 as much as from HLA-B27 subtypes not associated to spondyloarthritis. Eur J Immunol 2006; 36:1867-81. [PMID: 16783853 DOI: 10.1002/eji.200635896] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
HLA-B*2707 is associated with ankylosing spondylitis in most populations. Like the non-associated allotypes B*2706 and B*2709, it lacks Asp116 and shows preference for peptides with nonpolar C-terminal residues. The relationships between the peptide specificity of B*2707 and those of the disease-associated B*2705 and the non-associated subtypes were analyzed by determining the overlap between the corresponding peptide repertoires, the sequence of shared and differential ligands, and by comparing allospecific T cell epitopes with peptide sharing. The B*2707-bound repertoire was as different from that of B*2705 as from those of B*2706, B*2709, or the two latter subtypes from each other. Differences between B*2707 and B*2705 were based on their C-terminal residue specificity and a subtle modulation at other positions. Differential usage of secondary anchor residues explained the disparity between the B*2707-, B*2706-, and B*2709-bound repertoires. Similar differences in residue usage were found between B*2707 and both B*2704 and B*2706, as expected from the high peptide overlap between the two latter subtypes. T cell cross-reaction paralleled peptide sharing, suggesting that many shared ligands conserve their alloantigenic features on distinct subtypes. Our results indicate that association of HLA-B27 subtypes with ankylosing spondylitis does not correlate with higher peptide sharing among disease-associated subtypes or with obvious peptide motifs.
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Affiliation(s)
- Patricia Gómez
- Centro de Biología Molecular Severo Ochoa (Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid), Facultad de Ciencias, Universidad Autónoma, Madrid, Spain
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44
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Wucherpfennig KW. The structural interactions between T cell receptors and MHC-peptide complexes place physical limits on self-nonself discrimination. Curr Top Microbiol Immunol 2006; 296:19-37. [PMID: 16329190 DOI: 10.1007/3-540-30791-5_2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/23/2023]
Abstract
The activation and expansion of T cells in an antimicrobial immune response is based on the ability of T cell receptors (TCR) to discriminate between MHC-bound peptides derived from different microbial agents as well as self-proteins. However, the specificity of T cells is constrained by the limited number of peptide side chains that are available for TCR binding. By considering the structural requirements for peptide binding to MHC molecules and TCR recognition of MHC-peptide complexes, we demonstrated that human T cell clones could recognize a number of peptides from different organisms that were remarkably distinct in their primary sequence. These peptides were particularly diverse at those sequence positions buried in pockets of the MHC binding site, whereas a higher degree of similarity was present at a limited number of peptide residues that created the interface with the TCR. These T cell clones had been isolated from multiple sclerosis patients with human myelin basic protein, demonstrating that activation of such autoreactive T cells by microbial peptides with sufficient structural similarity may contribute to the disease process. Similar findings have now been made for a variety of human and murine T cell clones, indicating that specificity and cross-reactivity are inherent properties of TCR recognition. The observations that particular TCR are highly sensitive to changes at particular peptide positions but insensitive to many other changes in peptide sequence are not contradictory, but rather the result of structural interactions in which a relatively flat TCR surface contacts a limited number of side chains from a peptide that is deeply embedded in the MHC binding site.
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Affiliation(s)
- K W Wucherpfennig
- Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, Boston, MA 02115, USA.
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45
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Merino E, Montserrat V, Paradela A, López de Castro JA. Two HLA-B14 subtypes (B*1402 and B*1403) differentially associated with ankylosing spondylitis differ substantially in peptide specificity but have limited peptide and T-cell epitope sharing with HLA-B27. J Biol Chem 2005; 280:35868-80. [PMID: 16115862 DOI: 10.1074/jbc.m505641200] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The peptide specificity of HLA-B*1403, an allotype associated with ankylosing spondylitis (Lopez-Larrea, C., Mijiyawa, M., Gonzalez, S., Fernandez-Morera, J. L., Blanco-Gelaz, M. A., Martinez-Borra, J., and Lopez-Vazquez, A. (2002) Arthritis Rheum. 46, 2968-2971) was compared with those of the non-associated B*1402 and the prototypic disease-associated B*2705 allotypes. Although differing by a single residue (L156R), B*1402 and B*1403 shared only 32-35% of their peptide repertoires. Subtype-related differences observed in multiple peptide positions, including P3 and P7, were largely explained by a direct effect of the L156R change on peptide specificity. The HLA-B14 subtypes shared only approximately 3% of their peptide repertoires with B*2705. This was due to distinct residue usage at most positions, as revealed by statistical comparison of B*1402, B*1403, and B*2705-bound nonamers. Nevertheless, shared ligands between B*2705 and B*1403 were formally identified, although ligands common to B*2705 and B*1403, but absent from B*1402, were not found. Alloreactive T-cells were used as a tool to analyze epitope sharing among B*1402, B*1403, and B*2705. The percentage of cross-reactive T-cell clones closely paralleled peptide overlap, suggesting that shared ligands tend to maintain their antigenic features when bound to the different allotypes. Our results indicate that B*1403 and B*2705 can present common peptides. However, both the disparity of their peptide repertoires and the lack of binding features shared by these two allotypes, but not B*1402, argue against, although do not exclude, a mechanism of spondyloarthritis mediated by specific ligands of B*2705 and B*1403.
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Affiliation(s)
- Elena Merino
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid, Facultad de Ciencias, Universidad Autónoma, 28049 Madrid, Spain
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46
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Han B, Serra P, Yamanouchi J, Amrani A, Elliott JF, Dickie P, Dilorenzo TP, Santamaria P. Developmental control of CD8 T cell-avidity maturation in autoimmune diabetes. J Clin Invest 2005; 115:1879-87. [PMID: 15937548 PMCID: PMC1142112 DOI: 10.1172/jci24219] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2004] [Accepted: 04/26/2005] [Indexed: 11/17/2022] Open
Abstract
The progression of immune responses is generally associated with an increase in the overall avidity of antigen-specific T cell populations for peptide-MHC. This is thought to result from preferential expansion of high-avidity clonotypes at the expense of their low-avidity counterparts. Since T cell antigen-receptor genes do not mutate, it is puzzling that high-avidity clonotypes do not predominate from the outset. Here we provide a developmental basis for this phenomenon in the context of autoimmunity. We have carried out comprehensive studies of the diabetogenic CD8 T cell population that targets residues 206-214 of the beta cell antigen islet-specific glucose-6-phosphatase catalytic subunit-related protein (IGRP(206-214)) and undergoes avidity maturation as disease progresses. We find that the succession of IGRP(206-214)-specific clonotypes with increasing avidities during the progression of islet inflammation to overt diabetes in nonobese diabetic mice is fueled by autoimmune inflammation but opposed by systemic tolerance. As expected, naive high-avidity IGRP(206-214)-specific T cells respond more efficiently to antigen and are significantly more diabetogenic than their intermediate- or low-avidity counterparts. However, central and peripheral tolerance selectively limit the contribution of these high-avidity T cells to the earliest stages of disease without abrogating their ability to progressively accumulate in inflamed islets and kill beta cells. These results illustrate the way in which incomplete deletion of autoreactive T cell populations of relatively high avidity can contribute to the development of pathogenic autoimmunity in the periphery.
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Affiliation(s)
- Bingye Han
- Department of Microbiology and Infectious Diseases, Julia McFarlane Diabetes Research Centre, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada
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47
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Sandalova T, Michaëlsson J, Harris RA, Odeberg J, Schneider G, Kärre K, Achour A. A structural basis for CD8+ T cell-dependent recognition of non-homologous peptide ligands: implications for molecular mimicry in autoreactivity. J Biol Chem 2005; 280:27069-75. [PMID: 15845547 DOI: 10.1074/jbc.m500927200] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Molecular mimicry of self-epitopes by viral antigens is one possible pathogenic mechanism underlying induction of autoimmunity. A self-epitope, mDBM, derived from mouse dopamine beta-mono-oxygenase (KALYDYAPI) sharing 44% sequence identity with the lymphocytic choriomeningitis virus-derived immunodominant epitope gp33 (KAVYNFATC/M), has previously been identified as a cross-reactive self-ligand, presentation of which results in autoimmunity. A rat peptide homologue, rDBM (KALYNYAPI, 56% identity to gp33), which displayed similar properties to mDBM, has also been identified. We herein report the crystal structure of H-2Db.rDBM and a comparison with the crystal structures of the cross-reactive H-2Db.gp33 and non-cross-reactive H-2Db.gp33 (V3L) escape variant (KALYNFATM, 88% identity to gp33). Despite the large sequence disparity, rDBM and gp33 peptides are presented in nearly identical manners by H-2Db, with a striking juxtaposition of the central sections of both peptides from residues p3 to p7. The structural similarity provides H-2Db in complex with either a virus-derived or a dopamine beta-mono-oxygenase-derived peptide with a shared antigenic identity that conserves the positioning of the heavy chain and peptide residues that interact with the T cell receptor (TCR). This stands in contrast to the structure of H-2Db.gp33 (V3L), in which a single conserved mutation, also present in rDBM, induces large movements of both the peptide backbone and the side chains that interact with the TCR. The TCR-interacting surfaces of the H-2Db.rDBM and H-2Db.gp33 major histocompatibility complexes are very similar with regard to shape, topology, and charge distribution, providing a structural basis for CD8 T cell activation by molecular mimicry and potential subsequent development of autoreactivity.
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Affiliation(s)
- Tatyana Sandalova
- Department of Medical Biochemistry and Biophysics, Microbiology and Tumor Biology Center, and Strategic Research Center IRIS for Studies of Integrated Recognition in the Immune System, Karolinska Institutet, SE-171 77 Stockholm, Sweden
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Wheatland R. Molecular mimicry of ACTH in SARS - implications for corticosteroid treatment and prophylaxis. Med Hypotheses 2005; 63:855-62. [PMID: 15488660 PMCID: PMC7126000 DOI: 10.1016/j.mehy.2004.04.009] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2004] [Accepted: 04/14/2004] [Indexed: 01/21/2023]
Abstract
For a virus to survive and replicate in an organism, it must employ strategies to evade and misdirect the host's immune response. There is compelling evidence that the primary immunoevasive strategy utilized by the SARS virus, like influenza, is to inhibit its host's corticosteroid stress response. This is accomplished by viral expression of amino acid sequences that are molecular mimics of the host's adrenocorticotropin hormone (ACTH). When the host produces antibodies against these viral antigens, the antibodies also bind to the host's own ACTH, which limits the host's stress response by interfering with ACTH's ability to stimulate the secretion of corticosteroids. This inadequate corticosteroid response provokes symptoms as a result of a relative adrenocortical insufficiency. Treatment with corticosteroids can relieve the patient's symptoms of adrenocortical insufficiency and give them the corticosteroid levels needed to fight their infection. Similarly, by taking moderate daily doses of corticosteroids as a prophylactic, it may be possible to avoid clinical infection with SARS. If SARS's ACTH mimic strategy never has an opportunity to get started, SARS's ability to evade its host's immune system while its viral load is low will be significantly impaired. In this article, amino acid sequences from the SARS and influenza viruses representing likely homology to human ACTH are identified. Evidence demonstrating that ACTH autoantibodies are produced during influenza infection is also presented. Early treatment with corticosteroids should lower the dose necessary to counteract SARS's ACTH autoantibody mechanism. If corticosteroid treatment is delayed until inflammatory cytokine levels are causing serious injury, only high doses of corticosteroids are likely to be effective.
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Affiliation(s)
- R Wheatland
- The Endocrine Research Project, 574 Sims Road, Santa Cruz, CA 95060, USA.
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Luo W, Hsu JCF, Kieber-Emmons T, Wang X, Ferrone S. Human tumor associated antigen mimicry by xenoantigens, anti-idiotypic antibodies and peptide mimics: Implications for immunotherapy of malignant diseases. ACTA ACUST UNITED AC 2005; 22:769-87. [PMID: 16110640 DOI: 10.1016/s0921-4410(04)22036-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Affiliation(s)
- Wei Luo
- Department of Immunology, Roswell Park Cancer Institute, Buffalo, NY 14263, USA
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Ryan KR, McNeil LK, Dao C, Jensen PE, Evavold BD. Modification of peptide interaction with MHC creates TCR partial agonists. Cell Immunol 2004; 227:70-8. [PMID: 15051516 DOI: 10.1016/j.cellimm.2004.01.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2003] [Accepted: 01/16/2004] [Indexed: 10/26/2022]
Abstract
We report the creation of TCR partial agonists by the novel approach of manipulating the interaction between immunogenic peptide and MHC. Amino acids at MHC anchor positions of the I-E(k)-restricted hemoglobin (64-76) and moth cytochrome c (88-103) peptides were exchanged with MHC anchor residues from the low affinity class II invariant chain peptide (CLIP), resulting in antigenic peptides with altered affinity for MHC class II. Several low affinity peptides were identified as TCR partial agonists, as defined by the ability to stimulate cytolytic function but not proliferation. For example, a peptide containing methionine substitutions at positions one and nine of the I-E(k) binding motif acted as a partial agonist for two hemoglobin-reactive T cell clones (PL.17 and 3.L2). The identical MHC anchor substitutions in moth cytochrome c (88-103) also created a partial agonist for a mCC-reactive T cell (A.E7). Thus, peptides containing MHC anchor modifications mediated similar T cell responses regardless of TCR fine specificity or antigen reactivity. This data contrasts with the unique specificity among individual clones demonstrated using traditional altered peptide ligands containing substitutions at TCR contact residues. In conclusion, we demonstrate that altering the MHC anchor residues of the immunogenic peptide can be a powerful method to create TCR partial agonists.
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Affiliation(s)
- Kelli R Ryan
- Graduate Program in Immunology and Molecular Pathogenesis, Department of Microbiology and Immunology, Emory University, 1510 Clifton Rd. Atlanta, GA 30322, USA
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