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Ma K, Chai Y, Guan J, Tan S, Qi J, Kawana-Tachikawa A, Dong T, Iwamoto A, Shi Y, Gao GF. Molecular Basis for the Recognition of HIV Nef138-8 Epitope by a Pair of Human Public T Cell Receptors. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2022; 209:1652-1661. [PMID: 36130828 DOI: 10.4049/jimmunol.2200191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 08/30/2022] [Indexed: 11/07/2022]
Abstract
Cross-recognized public TCRs against HIV epitopes have been proposed to be important for the control of AIDS disease progression and HIV variants. The overlapping Nef138-8 and Nef138-10 peptides from the HIV Nef protein are HLA-A24-restricted immunodominant T cell epitopes, and an HIV mutant strain with a Y139F substitution in Nef protein can result in immune escape and is widespread in Japan. Here, we identified a pair of public TCRs specific to the HLA-A24-restricted Nef-138-8 epitope using PBMCs from White and Japanese patients, respectively, namely TD08 and H25-11. The gene use of the variable domain for TD08 and H25-11 is TRAV8-3, TRAJ10 for the α-chain and TRBV7-9, TRBD1*01, TRBJ2-5 for the β-chain. Both TCRs can recognize wild-type and Y2F-mutated Nef138-8 epitopes. We further determined three complex structures, including TD08/HLA-A24-Nef138-8, H25-11/HLA-A24-Nef138-8, and TD08/HLA-A24-Nef138-8 (2F). Then, we revealed the molecular basis of the public TCR binding to the peptide HLA, which mostly relies on the interaction between the TCR and HLA and can tolerate the mutation in the Nef138-8 peptide. These findings promote the molecular understanding of T cell immunity against HIV epitopes and provide an important basis for the engineering of TCRs to develop T cell-based immunotherapy against HIV infection.
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Affiliation(s)
- Keke Ma
- Savaid Medical School, University of Chinese Academy of Sciences, Beijing, China.,Chinese Academy of Sciences Key Laboratory of Pathogen Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Yan Chai
- Chinese Academy of Sciences Key Laboratory of Pathogen Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Jiawei Guan
- Chinese Academy of Sciences Key Laboratory of Pathogen Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Shuguang Tan
- Chinese Academy of Sciences Key Laboratory of Pathogen Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Jianxun Qi
- Chinese Academy of Sciences Key Laboratory of Pathogen Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Ai Kawana-Tachikawa
- AIDS Research Center, National Institute of Infectious Diseases, Tokyo, Japan
| | - Tao Dong
- Chinese Academy of Medical Sciences Oxford Institute, Nuffield Department of Medicine, Oxford University, Oxford, UK; and
| | - Aikichi Iwamoto
- Department of Research Promotion, Japan Agency for Medical Research and Development, Tokyo, Japan
| | - Yi Shi
- Savaid Medical School, University of Chinese Academy of Sciences, Beijing, China; .,Chinese Academy of Sciences Key Laboratory of Pathogen Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - George F Gao
- Savaid Medical School, University of Chinese Academy of Sciences, Beijing, China; .,Chinese Academy of Sciences Key Laboratory of Pathogen Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
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Sánchez-Martínez A, Acevedo-Sáenz L, Alzate-Ángel JC, Álvarez CM, Guzmán F, Roman T, Urcuqui-Inchima S, Cardona-Maya WD, Velilla PA. Functional Profile of CD8 + T-Cells in Response to HLA-A*02:01-Restricted Mutated Epitopes Derived from the Gag Protein of Circulating HIV-1 Strains from Medellín, Colombia. Front Immunol 2022; 13:793982. [PMID: 35392101 PMCID: PMC8980466 DOI: 10.3389/fimmu.2022.793982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Accepted: 02/28/2022] [Indexed: 11/13/2022] Open
Abstract
CD8+ T-cells play a crucial role in the control of HIV replication. HIV-specific CD8+ T-cell responses rapidly expand since the acute phase of the infection, and it has been observed that HIV controllers harbor CD8+ T-cells with potent anti-HIV capacity. The development of CD8+ T-cell-based vaccine against HIV-1 has focused on searching for immunodominant epitopes. However, the strong immune pressure of CD8+ T-cells causes the selection of viral variants with mutations in immunodominant epitopes. Since HIV-1 mutations are selected under the context of a specific HLA-I, the circulation of viral variants with these mutations is highly predictable based on the most prevalent HLA-I within a population. We previously demonstrated the adaptation of circulating strains of HIV-1 to the HLA-A*02 molecule by identifying mutations under positive selection located in GC9 and SL9 epitopes derived from the Gag protein. Also, we used an in silico prediction approach and evaluated whether the mutations found had a higher or lower affinity to the HLA-A*02. Although this strategy allowed predicting the interaction between mutated peptides and HLA-I, the functional response of CD8+ T-cells that these peptides induce is unknown. In the present work, peripheral blood mononuclear cells from 12 HIV-1+ HLA-A*02:01+ individuals were stimulated with the mutated and wild-type peptides derived from the GC9 and SL9 epitopes. The functional profile of CD8+ T-cells was evaluated using flow cytometry, and the frequency of subpopulations was determined according to their number of functions and the polyfunctionality index. The results suggest that the quality of the response (polyfunctionality) could be associated with the binding affinity of the peptide to the HLA molecule, and the functional profile of specific CD8+ T-cells to mutated epitopes in individuals under cART is maintained.
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Affiliation(s)
- Alexandra Sánchez-Martínez
- Grupo Inmunovirología, Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad de Antioquia UdeA, Medellín, Colombia
| | - Liliana Acevedo-Sáenz
- Grupo Cuidado Enfermería CES, Facultad de Enfermería, Universidad CES, Medellín, Colombia
| | - Juan Carlos Alzate-Ángel
- Grupo Inmunovirología, Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad de Antioquia UdeA, Medellín, Colombia.,Unidad de Micología Médica y Experimental, Corporación para Investigaciones Biológicas, Medellín, Universidad de Santander (CIB-UDES), Bucaramanga, Colombia
| | - Cristian M Álvarez
- Grupo de Inmunología Celular e Inmunogenética, Facultad de Medicina, Universidad de Antioquia UdeA, Medellín, Colombia
| | - Fanny Guzmán
- Núcleo de Biotecnología Curauma, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
| | - Tanya Roman
- Núcleo de Biotecnología Curauma, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
| | - Silvio Urcuqui-Inchima
- Grupo Inmunovirología, Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad de Antioquia UdeA, Medellín, Colombia
| | - Walter D Cardona-Maya
- Grupo Reproducción, Facultad de Medicina, Universidad de Antioquia UdeA, Medellín, Colombia
| | - Paula Andrea Velilla
- Grupo Inmunovirología, Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad de Antioquia UdeA, Medellín, Colombia
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3
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Pinilla C, Giulianotti MA, Santos RG, Houghten RA. Identification of B Cell and T Cell Epitopes Using Synthetic Peptide Combinatorial Libraries. Curr Protoc 2022; 2:e378. [PMID: 35263045 DOI: 10.1002/cpz1.378] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
This article presents a combinatorial library method that consists of the synthesis and screening of mixture-based synthetic combinatorial libraries of peptide molecules to identify B and T cell epitopes. The protocols employ peptide libraries to identify peptides recognized by MAbs and T cells. The first protocol uses a positional scanning peptide library made up of hexapeptides to identify antigenic determinants recognized by MAbs. The 120 mixtures in the hexapeptide library are tested for their inhibitory activity in a competitive ELISA. The second protocol uses a decapeptide library to identify T cell peptide ligands. The 200 mixtures of the decapeptide library are tested for their ability to induce T cell activation. Support protocols cover optimization of the assay conditions for each MAb or T cell, to achieve the best level of sensitivity and reproducibility, and preparation of a hexapeptide library, along with deconvolution approaches. © 2022 Wiley Periodicals LLC. Basic Protocol 1: Screening peptide library for antibody inhibition Basic Protocol 2: Screening a peptide library to identify CD4+ Or CD8+ T cell ligands Support Protocol 1: Optimizing antigen and antibody concentrations for screening assay Support Protocol 2: Preparing a positional scanning peptide library.
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Affiliation(s)
- Clemencia Pinilla
- Center for Translational Science, Florida International University, Port St. Lucie, Florida
| | - Marc A Giulianotti
- Center for Translational Science, Florida International University, Port St. Lucie, Florida
| | | | - Richard A Houghten
- Center for Translational Science, Florida International University, Port St. Lucie, Florida
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Debebe BJ, Boelen L, Lee JC, Thio CL, Astemborski J, Kirk G, Khakoo SI, Donfield SM, Goedert JJ, Asquith B. Identifying the immune interactions underlying HLA class I disease associations. eLife 2020; 9:54558. [PMID: 32238263 PMCID: PMC7253178 DOI: 10.7554/elife.54558] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 03/06/2020] [Indexed: 12/11/2022] Open
Abstract
Variation in the risk and severity of many autoimmune diseases, malignancies and infections is strongly associated with polymorphisms at the HLA class I loci. These genetic associations provide a powerful opportunity for understanding the etiology of human disease. HLA class I associations are often interpreted in the light of 'protective' or 'detrimental' CD8+ T cell responses which are restricted by the host HLA class I allotype. However, given the diverse receptors which are bound by HLA class I molecules, alternative interpretations are possible. As well as binding T cell receptors on CD8+ T cells, HLA class I molecules are important ligands for inhibitory and activating killer immunoglobulin-like receptors (KIRs) which are found on natural killer cells and some T cells; for the CD94:NKG2 family of receptors also expressed mainly by NK cells and for leukocyte immunoglobulin-like receptors (LILRs) on myeloid cells. The aim of this study is to develop an immunogenetic approach for identifying and quantifying the relative contribution of different receptor-ligand interactions to a given HLA class I disease association and then to use this approach to investigate the immune interactions underlying HLA class I disease associations in three viral infections: Human T cell Leukemia Virus type 1, Human Immunodeficiency Virus type 1 and Hepatitis C Virus as well as in the inflammatory condition Crohn's disease.
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Affiliation(s)
- Bisrat J Debebe
- Department of Infectious Disease, Imperial College London, London, United Kingdom
| | - Lies Boelen
- Department of Infectious Disease, Imperial College London, London, United Kingdom
| | - James C Lee
- Cambridge Institute for Therapeutic Immunology and Infectious Disease, University of Cambridge, Cambridge, United Kingdom
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- Johns Hopkins University, Baltimore, United States.,Faculty of Medicine, University of Southampton, Southampton, United Kingdom
| | - Chloe L Thio
- Johns Hopkins University, Baltimore, United States
| | | | - Gregory Kirk
- Johns Hopkins University, Baltimore, United States
| | - Salim I Khakoo
- Faculty of Medicine, University of Southampton, Southampton, United Kingdom
| | | | - James J Goedert
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, Bethesda, United States
| | - Becca Asquith
- Department of Infectious Disease, Imperial College London, London, United Kingdom
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5
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Abstract
T cells recognize and respond to self antigens in both cancer and autoimmunity. One strategy to influence this response is to incorporate amino acid substitutions into these T cell-specific epitopes. This strategy is being reconsidered now with the goal of increasing time to regression with checkpoint blockade therapies in cancer and antigen-specific immunotherapies in autoimmunity. We discuss how these amino acid substitutions change the interactions with the MHC class I or II molecule and the responding T cell repertoire. Amino acid substitutions in epitopes that are the most effective in therapies bind more strongly to T cell receptor and/or MHC molecules and cross-react with the same repertoire of T cells as the natural antigen.
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Affiliation(s)
- Jill E Slansky
- Department of Immunology and Microbiology, University of Colorado School of Medicine, 12800 E. 19thAvenue, Aurora, CO 80045, USA.
| | - Maki Nakayama
- Department of Immunology and Microbiology, University of Colorado School of Medicine, 12800 E. 19thAvenue, Aurora, CO 80045, USA; Barbara Davis Center for Childhood Diabetes, University of Colorado School of Medicine, 1775 Aurora Court, Aurora, CO 80045, USA
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6
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Balamurugan A, Ng HL, Yang OO. Cross-Reactivity against Multiple HIV-1 Epitopes Is Characteristic of HIV-1-Specific Cytotoxic T Lymphocyte Clones. J Virol 2018; 92:e00617-18. [PMID: 29899094 PMCID: PMC6069174 DOI: 10.1128/jvi.00617-18] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Accepted: 06/05/2018] [Indexed: 11/20/2022] Open
Abstract
Although a high level of promiscuity for heterologous epitopes is believed to exist for cellular immunity, limited data explore this issue for human immunodeficiency virus type 1 (HIV-1)-specific CD8+ T lymphocyte (CTL) responses. Here, we found an unexpected degree of heterologous cross-reactivity against HIV-1 epitopes, in addition to the targeted index epitope. Most CTL clones screened cross-reacted against other known HIV-1 epitopes of the same major histocompatibility complex type I (MHC-I) restriction, up to 40% of tested nonindex epitopes in some cases. The observed cross-reactivity was universally lower avidity than recognition of the index epitope when examined for several A*02- and B*57-restricted CTL clones, demonstrating that the high concentrations of exogenous epitope typically used for screening of CTL responses are prone to detect such cross-reactivity spuriously. In agreement with this, we found that these cross-reactive responses do not appear to mediate CTL activity against HIV-1-infected cells. Overall, our data indicate that low-level cross-reactivity is remarkably common for HIV-1-specific CTLs. The role of this phenomenon is unclear, but low-avidity interactions have been shown to foster homeostatic proliferation of memory T cells.IMPORTANCE This study raises two issues related to HIV-1-specific CTL responses. These are key immune responses that retard disease progression in infected persons that are highly relevant to immunotherapies and vaccines for HIV-1. First, we make the novel observation that these responses are promiscuous and that CTLs targeting one epitope may cross-recognize other, completely distinct epitopes in the virus. While these are low-avidity interactions that do not appear to contribute directly to the antiviral activity of CTLs, this raises interesting biologic implications regarding the purpose of the phenomenon, such as providing a stimulus for these responses to persist long term. Second, the data raise a technical caveat to detection of CTL responses against particular epitopes, suggesting that some methodologies may unintentionally detect cross-reactivity and overestimate responses against an epitope.
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Affiliation(s)
- Arumugam Balamurugan
- Division of Infectious Diseases, Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California USA
- UCLA AIDS Institute, University of California, Los Angeles, Los Angeles, California, USA
| | - Hwee L Ng
- Division of Infectious Diseases, Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California USA
- UCLA AIDS Institute, University of California, Los Angeles, Los Angeles, California, USA
| | - Otto O Yang
- Division of Infectious Diseases, Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California USA
- UCLA AIDS Institute, University of California, Los Angeles, Los Angeles, California, USA
- Department of Microbiology, Immunology and Molecular Genetics, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California, USA
- AIDS Healthcare Foundation, Los Angeles, California, USA
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7
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Cross-Reactivity Between Influenza Matrix- and HIV-1 P17-Specific CTL-A Large Cohort Study. J Acquir Immune Defic Syndr 2015; 69:528-35. [PMID: 25900164 DOI: 10.1097/qai.0000000000000657] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND It has been reported that HIV-1-specific cytotoxic T cells (CTL) recognizing the HLA-A2-restricted p17 epitope SLYNTVATL (SL9) can cross-react with the HLA-A2-restricted influenza matrix epitope GILGFVFTL (GL9). So far, the prevalence of GL9-cross-reacting HIV-1-specific CTL in larger cohorts of HIV-1-infected patients is unknown, and there are no data yet on whether SL9/GL9-cross-reactive CTL may influence the course of HIV-1 infection. METHODS We analyzed the presence of SL9/GL9-cross-reacting CTL in a cohort of 175 HLA-A2-positive HIV-1-infected patients. Peripheral blood mononuclear cells were stimulated in vitro with SL9 and GL9 peptides, and outgrowing cell lines regarding cross-reactivity and recognition of viral variants in γ-interferon enzyme-linked immunospot assays were analyzed. RESULTS SL9- and GL9-specific CTL could be generated in 52.6% and 53.7% of 175 patients, respectively. Both SL9- and GL9-specific CTL were more frequently observed in patients on antiretroviral therapy (ART). Of the 92 SL9-specific CTL and the 94 GL9-specific CTL, 65.2% and 66%, respectively, showed at least partial SL9/GL9 cross-reactivity. SL9/GL9-cross-reactive CTL could be detected in 42.9% of the 175 patients. Recognition of SL9 was associated with lower viral loads and higher CD4 cell counts in patients on ART. Patients with GL9/SL9 cross-reactivity displayed similar CD4 cell counts than patients without GL9/SL9-cross-reactive cells. GL9/SL9-cross-reactive cells were associated with higher viral loads in patients on ART. CONCLUSIONS Partially SL9/GL9-cross-reactive CTL are frequently observed in HIV-1-infected patients. So far, we could not detect a significant influence of the presence of SL9/GL9-cross-reacting CTL on the course of HIV-1 infection.
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Calis JJA, Maybeno M, Greenbaum JA, Weiskopf D, De Silva AD, Sette A, Keşmir C, Peters B. Properties of MHC class I presented peptides that enhance immunogenicity. PLoS Comput Biol 2013; 9:e1003266. [PMID: 24204222 PMCID: PMC3808449 DOI: 10.1371/journal.pcbi.1003266] [Citation(s) in RCA: 509] [Impact Index Per Article: 46.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2012] [Accepted: 08/23/2013] [Indexed: 12/14/2022] Open
Abstract
T-cells have to recognize peptides presented on MHC molecules to be activated and elicit their effector functions. Several studies demonstrate that some peptides are more immunogenic than others and therefore more likely to be T-cell epitopes. We set out to determine which properties cause such differences in immunogenicity. To this end, we collected and analyzed a large set of data describing the immunogenicity of peptides presented on various MHC-I molecules. Two main conclusions could be drawn from this analysis: First, in line with previous observations, we showed that positions P4–6 of a presented peptide are more important for immunogenicity. Second, some amino acids, especially those with large and aromatic side chains, are associated with immunogenicity. This information was combined into a simple model that was used to demonstrate that immunogenicity is, to a certain extent, predictable. This model (made available at http://tools.iedb.org/immunogenicity/) was validated with data from two independent epitope discovery studies. Interestingly, with this model we could show that T-cells are equipped to better recognize viral than human (self) peptides. After the past successful elucidation of different steps in the MHC-I presentation pathway, the identification of variables that influence immunogenicity will be an important next step in the investigation of T-cell epitopes and our understanding of cellular immune responses. T-cells have to recognize peptides presented on MHC molecules to be activated and elicit their effector functions. Some peptide-MHC-I complexes (pMHCs) are better recognized by T-cells; we call such pMHCs more immunogenic. For other pMHCs, no recognizing T-cells seem to exist; we call such pMHCs non-immunogenic. We set out to determine which properties of pMHCs cause such differences in immunogenicity, by carefully collecting a large set of immunogenic and non-immunogenic pMHCs, and analysing the difference between these sets. Two important observations were made: First, in line with previous observations, we showed that positions P4–6 of a presented peptide are more important for immunogenicity. Second, some amino acids, especially those with large and aromatic side chains, seem to be better recognized by T-cells as they associate with immunogenicity. Next, this information was combined into a simple model to predict the immunogenicity of new pMHCs (this model is made available at http://tools.iedb.org/immunogenicity/). Interestingly, with this model we could show that T-cells are equipped to strongly recognize viral peptides. After the past successful elucidation of different steps in the MHC-I presentation pathway, the identification of variables that influence immunogenicity will be an important next step in the investigation of T-cell epitopes and our understanding of cellular immune responses.
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Affiliation(s)
- Jorg J. A. Calis
- Theoretical Biology & Bioinformatics, Utrecht University, Utrecht, The Netherlands
- * E-mail:
| | - Matt Maybeno
- Division of Vaccine Discovery, La Jolla Institute for Allergy and Immunology, La Jolla, California, United States of America
| | - Jason A. Greenbaum
- Division of Vaccine Discovery, La Jolla Institute for Allergy and Immunology, La Jolla, California, United States of America
| | - Daniela Weiskopf
- Division of Vaccine Discovery, La Jolla Institute for Allergy and Immunology, La Jolla, California, United States of America
| | - Aruna D. De Silva
- Division of Vaccine Discovery, La Jolla Institute for Allergy and Immunology, La Jolla, California, United States of America
- Genetech Research Institute, Colombo, Sri Lanka
| | - Alessandro Sette
- Division of Vaccine Discovery, La Jolla Institute for Allergy and Immunology, La Jolla, California, United States of America
| | - Can Keşmir
- Theoretical Biology & Bioinformatics, Utrecht University, Utrecht, The Netherlands
| | - Bjoern Peters
- Division of Vaccine Discovery, La Jolla Institute for Allergy and Immunology, La Jolla, California, United States of America
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Pinilla C, Appel JR, Judkowski V, Houghten RA. Identification of B cell and T cell epitopes using synthetic peptide combinatorial libraries. CURRENT PROTOCOLS IN IMMUNOLOGY 2012; Chapter 9:9.5.1-9.5.16. [PMID: 23129156 PMCID: PMC3511046 DOI: 10.1002/0471142735.im0905s99] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
This unit presents a combinatorial library method that consists of the synthesis and screening of mixture-based synthetic combinatorial libraries of peptide molecules. The protocols employ peptide libraries to identify peptides recognized by MAbs and T cells. The first protocol uses a positional scanning peptide library made up of hexapeptides to identify antigenic determinants recognized by MAbs. The 120 mixtures in the hexapeptide library are tested for their inhibitory activity in a competitive ELISA. The second protocol uses a decapeptide library to identify T cell peptide ligands. The 200 mixtures of the decapeptide library are tested for their ability to induce T cell activation. Support protocols cover optimization of the assay conditions for each MAb or T cell, to achieve the best level of sensitivity and reproducibility, and preparation of a hexapeptide library, along with deconvolution approaches.
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Affiliation(s)
| | - Jon R Appel
- Torrey Pines Institute for Molecular Studies, San Diego, California
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10
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Calis JJA, de Boer RJ, Keşmir C. Degenerate T-cell recognition of peptides on MHC molecules creates large holes in the T-cell repertoire. PLoS Comput Biol 2012; 8:e1002412. [PMID: 22396638 PMCID: PMC3291541 DOI: 10.1371/journal.pcbi.1002412] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2011] [Accepted: 01/18/2012] [Indexed: 11/18/2022] Open
Abstract
The cellular immune system screens peptides presented by host cells on MHC molecules to assess if the cells are infected. In this study we examined whether the presented peptides contain enough information for a proper self/nonself assessment by comparing the presented human (self) and bacterial or viral (nonself) peptides on a large number of MHC molecules. For all MHC molecules tested, only a small fraction of the presented nonself peptides from 174 species of bacteria and 1000 viral proteomes ([Formula: see text]0.2%) is shown to be identical to a presented self peptide. Next, we use available data on T-cell receptor-peptide-MHC interactions to estimate how well T-cells distinguish between similar peptides. The recognition of a peptide-MHC by the T-cell receptor is flexible, and as a result, about one-third of the presented nonself peptides is expected to be indistinguishable (by T-cells) from presented self peptides. This suggests that T-cells are expected to remain tolerant for a large fraction of the presented nonself peptides, which provides an explanation for the "holes in the T-cell repertoire" that are found for a large fraction of foreign epitopes. Additionally, this overlap with self increases the need for efficient self tolerance, as many self-similar nonself peptides could initiate an autoimmune response. Degenerate recognition of peptide-MHC-I complexes by T-cells thus creates large and potentially dangerous overlaps between self and nonself.
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Affiliation(s)
- Jorg J A Calis
- Theoretical Biology & Bioinformatics, Utrecht University, Utrecht, The Netherlands.
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11
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Yerly D, Heckerman D, Allen T, Suscovich TJ, Jojic N, Kadie C, Pichler WJ, Cerny A, Brander C. Design, expression, and processing of epitomized hepatitis C virus-encoded CTL epitopes. THE JOURNAL OF IMMUNOLOGY 2009; 181:6361-70. [PMID: 18941227 DOI: 10.4049/jimmunol.181.9.6361] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Hepatitis C virus (HCV) vaccine efficacy may crucially depend on immunogen length and coverage of viral sequence diversity. However, covering a considerable proportion of the circulating viral sequence variants would likely require long immunogens, which for the conserved portions of the viral genome, would contain unnecessarily redundant sequence information. In this study, we present the design and in vitro performance analysis of a novel "epitome" approach that compresses frequent immune targets of the cellular immune response against HCV into a shorter immunogen sequence. Compression of immunological information is achieved by partial overlapping shared sequence motifs between individual epitopes. At the same time, sequence diversity coverage is provided by taking advantage of emerging cross-reactivity patterns among epitope variants so that epitope variants associated with the broadest variant cross-recognition are preferentially included. The processing and presentation analysis of specific epitopes included in such a compressed, in vitro-expressed HCV epitome indicated effective processing of a majority of tested epitopes, although re-presentation of some epitopes may require refined sequence design. Together, the present study establishes the epitome approach as a potential powerful tool for vaccine immunogen design, especially suitable for the induction of cellular immune responses against highly variable pathogens.
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Affiliation(s)
- Daniel Yerly
- Clinic for Rheumatology and Clinical Immunology, University of Bern, Bern, Switzerland
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12
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Blondelle SE, Moya-Castro R, Osawa K, Schroder K, Wilson DB. Immunogenically optimized peptides derived from natural mutants of HIV CTL epitopes and peptide combinatorial libraries. Biopolymers 2008; 90:683-94. [PMID: 18481808 DOI: 10.1002/bip.21020] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Two strategies were aimed at identifying immunogenically optimized peptides for the potential use in the formulation of an effective prophylactic or therapeutic HIV-1 vaccine. Three CTL epitopes were investigated: Gag p24(19-27) TV9, Gag p17(77-85) SL9, and RT(309-317) IV9. The first strategy derives from the hypothesis that a number of rare mutant CTL epitopes of HIV-1 may be more immunogenic than the common ones. As such, these rare mutant sequences might be highly effective in generating cross reactive anti-HIV-1 CTL responses against a range of mutant sequences. As anticipated, several rare mutant peptide sequences were identified that generated strong CTL responses against both the consensus sequences and several naturally occurring mutants in human PBL cultures primed ex vivo and in HLA-A2 transgenic mice immunized in vivo. Finally, to reach beyond the sequence diversity of the "natural" library of mutated sequences, a synthetic combinatorial peptide library was screened with a TV9 specific T-cell line; this resulted in the identification of an immunogenically optimized mimic peptide sequence that provoked highly effective CTL immune responses against TV9 and mutants. Sequence homologies between the natural mutants and synthetic mimic may provide insight into key contact positions in the MHC/TCR/peptide complex.
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Affiliation(s)
- Sylvie E Blondelle
- Mixture Sciences, Inc., 3550 General Atomics Ct, San Diego, CA 92121, USA.
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Capturing viral diversity for in-vitro test reagents and HIV vaccine immunogen design. Curr Opin HIV AIDS 2007; 2:183-8. [DOI: 10.1097/coh.0b013e3280f3bfe2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Bihl F, Frahm N, Di Giammarino L, Sidney J, John M, Yusim K, Woodberry T, Sango K, Hewitt HS, Henry L, Linde CH, Chisholm JV, Zaman TM, Pae E, Mallal S, Walker BD, Sette A, Korber BT, Heckerman D, Brander C. Impact of HLA-B Alleles, Epitope Binding Affinity, Functional Avidity, and Viral Coinfection on the Immunodominance of Virus-Specific CTL Responses. THE JOURNAL OF IMMUNOLOGY 2006; 176:4094-101. [PMID: 16547245 DOI: 10.4049/jimmunol.176.7.4094] [Citation(s) in RCA: 131] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Immunodominance is variably used to describe either the most frequently detectable response among tested individuals or the strongest response within a single individual, yet factors determining either inter- or intraindividual immunodominance are still poorly understood. More than 90 individuals were tested against 184 HIV- and 92 EBV-derived, previously defined CTL epitopes. The data show that HLA-B-restricted epitopes were significantly more frequently recognized than HLA-A- or HLA-C-restricted epitopes. HLA-B-restricted epitopes also induced responses of higher magnitude than did either HLA-A- or HLA-C-restricted epitopes, although this comparison only reached statistical significance for EBV epitopes. For both viruses, the magnitude and frequency of recognition were correlated with each other, but not with the epitope binding affinity to the restricting HLA allele. The presence or absence of HIV coinfection did not impact EBV epitope immunodominance patterns significantly. Peptide titration studies showed that the magnitude of responses was associated with high functional avidity, requiring low concentration of cognate peptide to respond in in vitro assays. The data support the important role of HLA-B alleles in antiviral immunity and afford a better understanding of the factors contributing to inter- and intraindividual immunodominance.
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Affiliation(s)
- Florian Bihl
- Partners AIDS Research Center, Massachusetts General Hospital, Charlestown, 02129, USA
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