Project description:A mutation that results in tumor rejection activity in a neoepitope (which is a poor binder of Kd) influences the immunogenicity of the tumor as a whole. Our results demonstrate the activity in vivo of a poorly-MHC I-binding cancer neoepitope.
Project description:By using >36,000 immunogenicity assay results, we developed a method to identify peptide-MHC complexes whose structural alignment facilitates T cell reaction. Our method accurately predicted neoepitopes for MHC II as well as MHC I that were responsive to checkpoint blockade when applied to >1,200 samples of various tumor types and on-therapy melanoma samples. To investigate selection by spontaneous immunity at the single epitope level, we analyzed the frequency spectrum of >25 million mutations in >9,000 treatment-naïve tumors in association with >100 immune phenotypes. MHC II immunogenicity specifically lowered variant frequencies in tumors under high immune pressure particularly with high TCR clonality and MHC II expression.
Project description:The immune response against tuberculosis relies, at least in part, on CD4+ T cells. Protective vaccines require the induction of antigen-specific CD4+ T cells via mycobacterial peptides presented by MHC class-II in infected macrophages. We have purified MHC class-I and MHC-II peptides and analysed them by mass spectrometry. We have successfully identified 97 mycobacterial peptides presented by MHC-II and 54 presented by MHC-I, from 76 and 41 antigens, respectively. The sequences of selected peptides were confirmed by spectral match validation and immunogenicity evaluated by IFN-gamma ELISpot against peripheral blood mononuclear cells from volunteers vaccinated with BCG, M.tb latently infected subjects or patients with tuberculosis disease. Three antigens were expressed in viral vectors, and evaluated as vaccine candidates alone or in combination in a murine aerosol M.tb challenge model. When delivered in combination, the three candidate vaccines conferred significant protection in the lungs and spleen compared with BCG alone, demonstrating proof-of-concept for this unbiased approach to identifying novel candidate antigens.
Project description:This mathematical model describes interactions between glioma tumors and the immune system that may occur following direct intra-tumoral administration of ex-vivo activated alloreactive cytotoxic-T-lymphocytes (aCTLs) as part of adoptive immunotherapy. The model includes descriptions of aCTL, neoplastic cells, MHC class I and II molecules, TGF-beta and IFN-gamma.
Project description:The appended raw files, csv files and other documents were deposited in the public domain in support for the publication "Expanding the MAPPs assay to accommodate MHC-II pan re-ceptors for improved predictability of potential T cell epitopes" by Katharina Hartman, Guido Steiner, Michel Siegel, Cary M. Looney, Timothy P. Hickling, Katharine Bray-French, Sebastian Springer, Celine Marban-Doran and Axel Ducret.
The abstract is as follows: A critical step in the immunogenicity cascade is attributed to human leukocyte antigen (HLA) II presentation triggering T cell immune responses. The liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based major histocompatibility complex (MHC) II-associated peptide proteomics (MAPPs) assay is implemented during preclinical risk assessments to identify bio-therapeutic-derived T cell epitopes. Although studies indicate HLA-DP and HLA-DQ alleles are linked to immunogenicity, most MAPPs studies are restricted to HLA-DR as the dominant HLA II genotype due to lack of well-characterized immunoprecipitating antibodies. Herein we ad-dress this issue by testing various commercially-available clones of MHC-II pan (CR3/43, WR18, and Tu39), HLA-DP (B7/21), and HLA-DQ (SPV-L3 and 1a3) antibodies in the MAPPs assay, and characterizing identified peptides according to binding specificity. Our results reveal that HLA II receptor-precipitating reagents with similar reported specificities differ based on clonality and that MHC-II pan antibodies do not entirely exhibit pan-specific tendencies. Since no individual antibody clone is able to recover the complete HLA II peptide repertoire, we recommend a mixed strategy of clones L243, WR18, and SPV-L3 in a single immunoprecipitation step for more robust compound-specific peptide detection. Ultimately, our optimized MAPPs strategy im-proves the predictability and additional identification of T cell epitopes in immunogenicity risk assessments.
The dataset is divided in two sections, one supporting the figures 1-4, the other one supporting the figure 5-6. The collective data has aslo be used to generate the supplementary tables S1-S9.
Project description:Decoy receptor 3 (DcR3) is a member of the TNF receptor superfamily and is up-regulated in tumors that originate from a diversity of lineages. DcR3 is capable of promoting angiogenesis, inducing dendritic cell apoptosis, and modulating macrophage differentiation. Since tumor-associated macrophages (TAMs) are the major infiltrating leukocytes in most malignant tumors, we used microarray technology to investigate whether DcR3 contributes to the development of TAMs. Among the DcR3-modulated genes expressed by TAMs, those that encode proteins involved in MHC class II (MHC-II)-dependent antigen presentation were down-regulated substantially, together with the master regulator of MHC-II expression (the class II transactivator, CIITA). The ERK- and JNK-induced deacetylation of histones associated with the CIITA promoters was responsible for DcR3-mediated down-regulation of MHC-II expression. Furthermore, the expression level of DcR3 in cancer cells correlated inversely with HLA-DR levels on TAMs and with the overall survival time of pancreatic cancer patients. The role of DcR3 in the development of TAMs was further confirmed using transgenic mice over-expressing DcR3. This elucidates the molecular mechanism of impaired MHC-II-mediated antigen presentation by TAMs, and raises the possibility that subversion of TAM-induced immunosuppression via inhibition of DcR3 expression might represent a target for the design of new therapeutics. Experiment Overall Design: Freshly isolated human monocytes were cultured with DcR3 or control hIgG1 in the presence of M-CSF for 2 days. Data were collected from two independent donors
Project description:Immune checkpoint blockade (ICB) therapy is a cornerstone of oncologic treatment for patients with advanced stage non-small cell lung cancer (NSCLC) and other malignancies. Neoantigen immunoediting drives ICB efficacy, yet the fundamental physiochemical characteristics of neoantigens and how neoantigen immunogenicity shapes treatment response remains poorly understood. To help address these questions, a prospective clinical trial of NSCLC patients treated with nivolumab was conducted. We assessed genomic alterations in tumors from 58 patients and performed large-scale neoepitope immunogenicity analyses, before and during treatment (CheckMate153, CA209-153). Tumors were analyzed by whole-exome and transcriptome sequencing. In responding patients, loss of mutation and neoantigen burden early during therapy associated with clinical benefit. We evaluated the immunogenicity of 1,453 candidate neoantigens and identified 502 neopeptides that bound to MHC I and 196 neopeptides that were immunogenically recognized by T cells in the setting of nivolumab treatment. These T cell reactive neoantigens were differentially present in clonal populations that underwent distinctive evolutionary trajectories across responders and nonresponders. Mapping these neoantigens to tumor clonal dynamics and clinical response revealed strong selection against immunogenic neoantigen harboring clones compared to non-immunogenic clones. Using this large collection of neoantigens, we identified position specific amino acid features related to immunogenicity, which we used to develop and validate an immunogenicity score. Changes in the genomic and neoantigen immunogenicity landscapes were accompanied by temporal changes in the tumor microenvironment. Nivolumab-induced microenvironmental evolution in NSCLC shared some similarities with that in melanoma, yet critical differences in immunologic programs were apparent from comparative network analysis between tumor types. This study provides unprecedented molecular portraits of the neoantigen landscapes underlying nivolumab’s mechanism of action.
Project description:Immune checkpoint blockade (ICB) therapy is a cornerstone of oncologic treatment for patients with advanced stage non-small cell lung cancer (NSCLC) and other malignancies. Neoantigen immunoediting drives ICB efficacy, yet the fundamental physiochemical characteristics of neoantigens and how neoantigen immunogenicity shapes treatment response remains poorly understood. To help address these questions, a prospective clinical trial of NSCLC patients treated with nivolumab was conducted. We assessed genomic alterations in tumors from 58 patients and performed large-scale neoepitope immunogenicity analyses, before and during treatment (CheckMate153, CA209-153). Tumors were analyzed by whole-exome and transcriptome sequencing. In responding patients, loss of mutation and neoantigen burden early during therapy associated with clinical benefit. We evaluated the immunogenicity of 1,453 candidate neoantigens and identified 502 neopeptides that bound to MHC I and 196 neopeptides that were immunogenically recognized by T cells in the setting of nivolumab treatment. These T cell reactive neoantigens were differentially present in clonal populations that underwent distinctive evolutionary trajectories across responders and nonresponders. Mapping these neoantigens to tumor clonal dynamics and clinical response revealed strong selection against immunogenic neoantigen harboring clones compared to non-immunogenic clones. Using this large collection of neoantigens, we identified position specific amino acid features related to immunogenicity, which we used to develop and validate an immunogenicity score. Changes in the genomic and neoantigen immunogenicity landscapes were accompanied by temporal changes in the tumor microenvironment. Nivolumab-induced microenvironmental evolution in NSCLC shared some similarities with that in melanoma, yet critical differences in immunologic programs were apparent from comparative network analysis between tumor types. This study provides unprecedented molecular portraits of the neoantigen landscapes underlying nivolumab’s mechanism of action.
Project description:Pluripotent stem cells, including human embryonic stem (hES) and human induced pluripotent stem (hiPS) cells, have been regarded as potential sources for cell-based transplantation therapy. However, the immunogenicity of these cells remains the major determinant for successful clinical application. We therefore studied multiple hES and hiPS cell lines for MHC expression, HLA haplotyping, expression of immune-related genes and T cell activation. The data showed lower levels of MHC class I (MHC-I), b2-microglobulin and HLA-E in undifferentiated stem cells, but the levels were increased to near the levels of somatic cells after co-treatment with interferon gamma. However, the percentages of cells expressing antigen presenting cell markers and MHC-II molecules remained consistently low. Activation of responder lymphocytes by the pluripotent stem cells was significantly lower than by allogeneic lymphocytes in mixed lymphocyte reactions. Finally, the data showed significant differential expression of immune privilege genes (TGF-beta2, Arginase 2, Indo1, GATA3, POMC, VIP, CACLA, CACLB, IL-1RN, CD95L, CR1L, Serpine 1, HMOX1, IL6, LGALS3, HEBP1, THBS1, CD59 and LGALS1) between pluripotent stem cells/derivatives and somatic cells. We concluded that pluripotent stem cell progeny may retain some level of immune privilege and will likely behave in a way different from those of somatic cells after transplantation. Confirmed hiPSC cells and their parental cells were selected for RNA extraction and Affymetrix array analysis. To minimize the clone variation, we selected two clones from each type of iPSC.