Project description:Although mutations may represent attractive targets for immunotherapy, direct identification of mutated peptide ligands isolated from human leukocyte antigens (HLA) on the surface of native tumor tissue has so far not been successful. Using advanced mass spectrometry (MS) analysis, we survey the melanoma-associated immunopeptidome to a depth of 95,500 patient-presented peptides. We thereby discover a large spectrum of attractive target antigen candidates including cancer testis antigens and phosphopeptides. Most importantly, we identify peptide ligands presented on native tumor tissue samples harboring somatic mutations. Four of eleven mutated ligands prove to be immunogenic by neoantigen-specific T-cell responses. Moreover, tumor-reactive T cells with specificity for selected neoantigens identified by MS are detected in the patient`s tumor and peripheral blood. We conclude that direct identification of mutated peptide ligands from primary tumor material by MS is possible and yields true neoepitopes with high relevance for immunotherapeutic strategies in cancer.
Project description:Although mutations may represent attractive targets for immunotherapy, direct identification of mutated peptide ligands isolated from human leukocyte antigens (HLA) on the surface of native tumor tissue has so far not been successful. Using advanced mass spectrometry (MS) analysis, we survey the melanoma-associated immunopeptidome to a depth of 95,500 patient-presented peptides. We thereby discover a large spectrum of attractive target antigen candidates including cancer testis antigens and phosphopeptides. Most importantly, we identify peptide ligands presented on native tumor tissue samples harboring somatic mutations. Four of eleven mutated ligands prove to be immunogenic by neoantigen-specific T-cell responses. Moreover, tumor-reactive T cells with specificity for selected neoantigens identified by MS are detected in the patient`s tumor and peripheral blood. We conclude that direct identification of mutated peptide ligands from primary tumor material by MS is possible and yields true neoepitopes with high relevance for immunotherapeutic strategies in cancer.
Project description:These data were used for prediction of neoantigens and minor histocompatibility mismatch antigens, which were subsequently used for design of a machine-learning algorithm for tumor-specific antigen (TSA) immunogenicity prediction. TSA vaccines are a growing area of study for cancer immunotherapy, but identification of clinically relevant targets remains a challenge. The study associated with these data provides the first description of a computational method for direct prediction of TSA immunogenicity trained entirely from validated TSA immunogenicity scores. This tool has allowed us to 1) predict for clinically efficacious TSA targets, 2) identify genomic correlates of TSA immunogenicity, and 3) demonstrate evidence of alternative out-of-frame TSAs which can promote anti-tumor immunity.
Project description:In order to identify relevant targets for cancer immunotherapy in breast cancer, we characterized the immunopeptidome of 26 primary breast cancer samples with a proteogenomic approach relying on RNA-seq and mass spectrometry (MS). We were able to describe the landscape of MHC-I associated peptides presented by breast cancer tumors. Furthermore, bioinformatic analysis allowed us to identify tumor-specific and tumor associated antigens, which can be used for the development of anti-cancer vaccines or as targets for engineered T-cells.
Project description:Persistent therapy-resistant leukemia progenitor cells (LPC) are a main cause of disease relapse and recurrence in acute myeloid leukemia (AML). Specific LPC-targeting therapies may thus improve treatment outcome of AML patients. We demonstrated that LPCs present human leukocyte antigen (HLA)-restricted cancer antigens that induce T cell responses allowing for immune surveillance of AML. Using a mass spectrometry-based immunopeptidomics approach, we characterized the antigenic landscape of patient LPCs and identified AML/LPC-associated HLA-presented antigens including mutation-derived and cryptic neoepitopes as prime targets for development of T cell-based immunotherapeutic approaches. We observed frequent spontaneous memory T cells targeting these AML/LPC-associated antigens in AML patients and showed that antigen-specific T cell recognition and HLA class II immunopeptidome diversity impacts clinical outcome. Our results pave the way for implementation of AML/LPC-associated antigens for T cell-based immunotherapeutic approaches to specifically target and eliminate residual LPCs in AML patients.
Project description:We performed whole exome sequencing of tumor- as well as PBMC-derived DNA of five melanoma patients for identification of naturally presented patient-specific neoepitopes.
