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:Through analyzing publicly available single-cell and bulk sequencing data from ICI-treated cohorts, ZNF180-regulome was predictive of ICI responses in independent bulk sequencing cohorts, and ZNF180+ tumors persisted after the therapy with immune-suppressive features such as MHC-I loss and CD155 expressions, the primary ligand to TIGIT inhibitory receptor. To investigate regulatory roles of ZNF180 to confer these immune suppressive phenotypes, we performed ZNF180 knock-down in melanoma cells in vitro with different genetic backgrounds, namely A375 (BRAF-mutant) and SKMEL147 (NRAS-mutant) cells, and performed RNA- and ATAC-sequencing. The integrative analysis revealed ZNF180 silencing promoted tumor immunogenicity through gain of accessibility on MHC-I/-II coding genes, CD155 down-regulation to avoid TIGIT/CD155 checkpoint signaling, and suppressed AP-1 transcription factor activities as the drivers of melanoma reprogramming towards MITFlowAXLhigh de-differentiated cells. Further, ZNF180 silencing increased CD4 helper T-cell infiltrations in tumors and regressed the tumors in vivo. Collectively, these results indicate ZNF180 is a tumor intrinsic regulator of melanoma plasticity to drive de-differentiated phenotypes with immune-suppressive features including loss of immunogenicity, T-cell inhibitory signals through TIGIT/CD155 checkpoint and exclusion of CD4 helper T-cells. As ZNF180-regulome manifests in non-metastatic melanoma in contrast to the current focus of standard-of-care ICI on the metastatic disease, these results establish ZNF180-regulome as a biomarker and novel therapeutic avenue for early stage melanoma to intervene ICI resistance.
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:While the IFN-γ-STAT1 signaling pathway is well-characterized in promoting MHC class II (MHC-II)-dependent antigen presentation within pro-inflammatory macrophages during acute infections, its functional dynamics in tumor-associated macrophages (TAMs) remain poorly understood. Here, we systematically investigated the immunomodulatory role of IFN-γ-STAT1 axis in TAMs through integrative bioinformatics and experimental validation. Transcriptomic analysis of tumor-infiltrating myeloid cells across multiple cancer cohorts revealed a strong correlation between STAT1 activation and MHC-II pathway enrichment, particularly in IFN-γ-high TAM subsets. To mechanistically dissect this relationship, we employed bone marrow-derived macrophages (BMDMs) polarized under tumor-conditioned media and subjected them to IFN-γ stimulation. Single-cell RNA sequencing demonstrated that IFN-γ triggered STAT1 nuclear translocation, upregulating MHC-II genes. Our findings establish IFN-γ-STAT1 as a master regulator of TAM immunogenicity, proposing targeted STAT1 activation as a strategy to overcome myeloid-driven immunosuppression in cancer.
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:MHC-I loss is a prevalent mechanism for immune evasion and resistance to immunotherapy. However, the mechanisms by which MHC-I loss shapes the tumor microenvironment (TME) and influences the interactions between MHC-I-deficient tumors and immune cells, ultimately affecting tumor growth, remain largely unknown. Here, we found that MHC-I/B2M loss increased tumor growth rates in the MC38, AKR and LLC1 tumor models, but surprisingly led to regression of Hepa1-6 tumors. The effect of MHC-I/B2M loss on tumor growth was associated with the changes in immune infiltrates. CD4+ T cell, NK cells and macrophages were required to suppress the growth of MHC-I-deficient Hepa1-6 tumors, with CD4+ T cells appearing essential for maintaining of the tumoricidal phenotype of monocytes/macrophages and for recruiting NK cells and monocytes/macrophages. Moreover, the differential infiltration of CD4+ T cells was attributed to the upregulation of CXCL16 expression in Hepa1-6 upon loss of MHC-I/B2M, and the downregulation of CXCL16 due to MHC-I deficiency in other tumor models. CXCL16 exhibited a potent antitumor effect on MHC-I-deficient tumors by recruiting CD4+ T cells. In summary, CXCL16-driven CD4+ T cells are central regulators of antitumor immunity against MHC-I-deficient tumors.