Identification of Vaccinia Virus HLA Class I Peptides Presented by the Immune System
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PROVIDER: PRJNA107915 | ENA |
REPOSITORIES: ENA
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Project description:Seeking to identify HLA class I peptides that originate from vaccinia virus proteins to understand the mechanism of immune protection. Note that vaccinia-infected B cells will still continue to present (primarily) a wide variety of peptides originating from endogenous proteins; this data set contains evidence for more than 5000 such peptides. The objective and challenge is to detect and identify the peptides that originate from the pathogen (vaccinia virus) in the presence (background) of this large number of endogensous 'self' peptides. Keywords: Peptide search results from multiple injections of multiple strong cation exchange fractions combined into one set of results.
2009-08-31 | GSE10549 | GEO
Project description:Specific alterations in protein post-translational modification (PTMs) are recognized hallmarks of diseases. These modifications potentially provide a unique disease-related source of Human Leukocyte Antigen (HLA) class I-presented peptide antigens that can elicit specific immune responses. Although, phosphorylated HLA peptides have received already some attention, the frequency and characteristics of arginine methylated HLA class I peptide presentation have not been explored in detail. In a model human B-cell line we detected by mass spectrometry (MS) 149 HLA class I peptides harboring mono- and/or di-methylated arginine residues. The source proteins of these antigens play important roles in signal transduction, gene transcription and DNA repair. A striking preference was observed in presentation of arginine (di)methylated peptides predicted to bind HLA-B*07 molecules, most likely because the binding motifs of this allele resemble the substrates for arginine methyl-transferases. The HLA-B*07 peptides were preferentially di-methylated at the P3 position in the sequence, thus consecutively to the proline anchor residue at position P2. Such a proline-arginine sequnce has been associated with the arginine methyl-transferases CARM1 and PRMT5. Making use of the specific neutral losses in the MS/MS spectra we could further assign most of the peptides to be asymmetrically di-methylated, most likely by CARM1. The here presented data expand our knowledge of processing and presentation of arginine (di)methylated HLA class I peptides, indicating that this type of modification is frequently presented for recognition by T-cells and might thus present a potential target for immunotherapy.
2016-08-15 | PXD004233 | Pride
Project description:T cell-mediated immunity seems to play a critical role against SARS-CoV-2 infection and establishing protective memory. Yet the repertoire of viral epitopes responsible for activation of T cell responses remains mostly unknown. Identification and characterization of viral peptides presented on class I human leukocyte antigen (HLA-I) will reveal the viral signatures as seen by cytotoxic T cells that can then be harnessed for the development of effective vaccines. Here, we report the first HLA-I immunopeptidome of SARS-CoV-2 in two human cell lines at different times post-infection using mass spectrometry. We found HLA-I peptides derived not only from canonical ORFs, but also from internal out-of-frame ORFs in Spike and Nucleoprotein not currently captured by vaccine approaches. Whole proteome analysis revealed that expression of ubiquitination pathway proteins, and the proteasome maturation protein, POMP, were significantly altered in infected cells. Retrospective analysis of computational predictions highlighted shortcomings of in silico-only approaches in recovering the observed viral epitopes. Finally, given the experimental evidence for endogenous processing and presentation of the viral peptides we detected, we estimated that at least one HLA-A, -B, or -C allele is covered by at least one peptide for 99% of the population. These biological insights and the list of naturally presented SARS-CoV-2 peptides will facilitate data-driven selection of peptides for immune monitoring and vaccine development.
2020-10-08 | GSE159191 | GEO
Project description:Immune checkpoint inhibitor and adoptive lymphocyte transfer-based therapies have shown great therapeutic potential for cancers with high tumor mutation burden (TMB). Here, we employed mass spectrometry (MS)-based proteogenomic large-scale profiling to identify potential immunogenic human leukocyte antigen (HLA) Class ǀ-presented peptides in both melanoma, a “hot tumor” with high TMB, and EGFR mutant lung adenocarcinoma, a “cold tumor” with low TMB. We used cell line and patient-specific databases constructed using variants identified from whole-exome sequencing, as well as a de novo search algorithm from the PEAKS search algorithm to interrogate the mass spectrometry data of the Class I immunopeptidome. We identified 12 mutant neoantigens. Several classes of tumor-associated antigen-derived peptides were also identified. We constructed a cancer germline (CG) antigen database with 285 antigens and identified 42 Class I-presented CG antigens. We identified more than 1000 post-translationally modified (PTM) peptides representing 58 different PTMs. Our results suggest that PTMs play a critical role impacting HLA-binding affinity dramatically. Finally, leveraging de novo search and an annotated lncRNA database, we developed a novel non-canonical peptide discovery pipeline to identify 44 lncRNA-derived peptides that are presented by Class I. We validated MS/MS spectra of select peptides using synthetic peptides and performed HLA Class I binding assays to demonstrate binding of select neo-peptides and lncRNA-derived peptides to Class I proteins. In summary, we provide direct evidence of HLA Class I presentation of a large number of mutant and tumor-associated peptides for potential use as vaccine or adoptive cell therapy in melanoma and EGFR mutant lung cancer.
2021-08-23 | PXD022949 | Pride
Project description:Treatment of cancer cells with anti-cancer drugs often fails to achieve complete remission. Yet, such drug treatments may induce alteration in the tumorâs gene expression patterns, including those of Cancer/Testis Antigens (CTA). The degradation products of such antigens can be presented as HLA peptides on the surface of the tumor cells and be developed into anti-cancer immunotherapeutics. For example, the DNA methyl transferase inhibitor, 5-aza-2'-deoxycytidine (Decitabine) has limited anti-tumor efficacy, yet it induces the expression of many genes, including CTAs that are normally silenced in the healthy adult tissues. In this study, the presentation of many new HLA peptides derived from CTAs and induced by Decitabine was demonstrated in three human Glioblastoma cell lines. Such presentation of CTA-derived HLA peptides can be exploited for development of new treatment modalities, combining drug treatment with anti-CTA targeted immunotherapy. The Decitabine-induced HLA peptidomes include many CTAs that are not normally detected in healthy tissues or in cancer cells, unless treated with the drug. In addition, the study included large-scale analyses of the simultaneous effects of Decitabine on the transcriptomes, proteomes and HLA peptidomes of the human Glioblastoma cells. It demonstrates the poor correlations between these three levels of gene expression, both in their total levels and in their response to the drug. The transcriptomes, proteomes and HLA peptidomes of the U-87, T98G and LNT-229 GBM human cell lines were analyzed before and after treatment with Decitabine. Overall, the RNA-Seq transcriptome analyses resulted in the identification of above 26000 transcripts, the proteome analyses identified about 7500 proteins and the HLA class I peptidome analyses resulted in above 25000 identified HLA peptides. Two biological repetitions of the transcriptome, three of the proteome and three of the HLA peptidome were performed with each of the cell lines and treatment, resulting in highly reproducible datasets.
2016-07-19 | E-GEOD-80137 | biostudies-arrayexpress
Project description:Skin sensitisation following the covalent modification of proteins by low molecular weight chemicals (haptenation) is mediated by cytotoxic T lymphocyte (CTL) recognition of human leukocyte antigen molecules (HLA) presented on the surface of almost all nucleated cells. There are three nonmutually exclusive models for how haptens mediate CTL recognition: direct stimulation by haptenated peptides; hapten modification of HLA leading to an altered HLA-peptide repertoire; or a hapten altered proteome leading to an an altered HLA-peptide repertoire. To address the mechanism in skin, we set out to utilise proteomic analysis of keratinocyte presented antigens following exposure to 2,4-dinitrochlorobenzene (DNCB). We show that following DNCB exposure, cultured keratinocytes present cysteine haptenated (dinitrophenylated) peptides in multiple HLA molecules. In addition, we find that one of the DNCB modified peptides derives from the active site of cytosolic glutathione-S transferase-ω. These results provide support for the hypothesis that a key mechanism of skin sensitisation is stimulation of CTLs by haptenated peptides.
2021-01-04 | PXD021373 | Pride
Project description:Prediction of HLA epitopes is important for the development of cancer immunotherapies and vaccines. However, current prediction algorithms have limited predictive power, in part because they were not trained on high-quality epitope datasets covering a broad range of HLA alleles. To enable prediction of endogenous HLA class I-associated peptides across a large fraction of the human population, we used mass spectrometry to profile >185,000 peptides eluted from 95 HLA-A, -B, -C and -G mono-allelic cell lines. We identified canonical peptide motifs per HLA allele, unique and shared binding submotifs across alleles and distinct motifs associated with different peptide lengths. By integrating these data with transcript abundance and peptide processing, we developed HLAthena, providing allele-and-length-specific and pan-allele-pan-length prediction models for endogenous peptide presentation. These models predicted endogenous HLA class I-associated ligands with 1.5-fold improvement in positive predictive value compared with existing tools and correctly identified >75% of HLA-bound peptides that were observed experimentally in 11 patient-derived tumor cell lines.
2019-12-16 | GSE131267 | GEO
Project description:The recent success of monoclonal antibody checkpoint inhibitor therapies that enhance the ability of CD8+ T cells to detect cancer-related antigenic peptides has refocused the need to fully understand the repertoire of peptides being presented to the immune system. Whilst the peptide ligandome presented by cell surface HLA class I molecules on cancer cells has been studied extensively, the ligandome of extracellular vesicles remains poorly defined. Here we report the HLA class I ligandome of both cell surface and extracellular vesicles from eight breast cancer cell lines (MCF7, MDA-MB-231, MDA-MB-361, MDA-MB-415, MDA-MB-453, HCC 1806, HCC 1395, and HCC 1954), and additionally the melanoma cell line ESTDAB-056 and the multiple myeloma line RPMI 8226. Utilising HLA class I immunoisolation and mass spectrometry we detected a total of 6574 peptides from the cell surface and 2461 peptides from the extracellular vesicles of the cell lines studied. Within the extracellular vesicle HLA class I ligandome we identified 150 peptides derived from tumour associated antigenic proteins, of which 19 peptides have been shown to elicit T cell responses in previous studies. Our data thus confirms for the first time the presence of clinically relevant tumour-associated antigenic peptides in the HLA class I ligandome present on EV.
2022-04-01 | PXD025345 | Pride
Project description:The identification of peptides presented by HLA class I molecules to CD8+ T cells – i.e. the HLA-I immunopeptidome - is a useful tool to fish epitopes suitable for vaccinations and immunotherapies against cancer, infection and autoimmunity. These peptides are mainly generated by proteasomes through peptide hydrolysis and peptide splicing. Post-translationally spliced epitopes can enlarge the antigenic landscape and thus immunotherapy efficacy. Their identification is challenging, and the few methods proposed so far hinted toward a controversial broad spectrum of cis-spliced peptide frequencies in HLA-I immunopeptidomes. We here developed a new method named SPI-ART, which can identify cis-spliced peptides in HLA-I immunopeptidomes with precision and recall outperforming all other methods. The benchmark of the methods’ performances provided the proper analytical framework to explain the discordant results published so far. It also allowed to estimate the frequency of cis-spliced peptides in HLA-I immunopeptidomes, and to shed light on the biochemistry of these unconventional peptides and their potential antigenicity.
2022-08-12 | PXD025346 | Pride