Low avidity T cells drive endogenous tumor immunity in mice and humans
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE282069 | GEO | 2024/12/25
REPOSITORIES: GEO
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Project description:A major barrier of vaccines as cancer treatment is their failure to activate and maintain a complete cancer-specific CD8+ effector T cell repertoire. Low avidity T cells are more likely to escape clonal deletion in the thymus when compared to higher avidity T cells, and therefore comprise the major population of effector T cells available for activation in cancer patients. However, low avidity T cells fail to traffic into the tumor microenvironment and function in eradicating tumor under optimal vaccination conditions as opposed to higher avidity T cells that escape clonal deletion and do function in tumor killing. We utilized high and low avidity TCR transgenic CD8+ T cells specific for the immunodominant epitope of HER-2/neu (RNEU420-429) to identify signaling pathways responsible for the inferior activity of low avidity T cells. Adoptive transfer of these cells into tumor-bearing vaccinated mice identified members of apoptosis pathways as being upregulated in low avidity T cells. The increased expression of pro-apoptotic proteins by low avidity T cells promoted their own cell death and also that of other tumor-specific CD8+ T cells within their local environment. Importantly, this pro-apoptotic effect was overcome using a strong costimulatory signal that prevents activation-induced cell death and enables low avidity T cells to traffic into the tumor and assist in tumor clearance. These findings identify new therapeutic opportunities for activating the most potent anticancer T cell responses. High and low avidity T cells were isolated from TCR transgenic mice and adoptively transferred into Cy-treated, vaccinated, neu-N mice. Three days after adoptive transfer T cells were isolated from the tumor draining nodes and RNA was extracted for gene expression analysis.
2014-01-14 | E-GEOD-54020 | biostudies-arrayexpress
Project description:Personalized cancer immunotherapies such as vaccines and T cell receptor (TCR)-transgenic T cells rely on the presentation of tumor-specific peptides by human leukocyte antigen (HLA) class I molecules to cytotoxic T cells. Such neoepitopes can for example arise from somatic mutations and their identification is crucial for the rational design of new therapeutic interventions. For their detection by liquid chromatography mass spectrometry (LC-MS), we have developed a parameter optimization workflow to tune targeted assays for maximum detection sensitivity on a per peptide basis, termed optiPRM. Optimization of collision energy using optiPRM allows for improved detection of low abundant peptides that are very hard to detect using standard parameters. Applying this for to immunopeptidomics, we detected a neoepitope in a patient-derived xenograft (PDX) from as little as 2.5×106 cells input. Application of the workflow on small patient tumor samples allowed for the detection of five mutation-derived neoepitopes in three patients. One neoepitope was confirmed to be recognized by patient T cells. In conclusion, we here present optiPRM, a targeted MS workflow reaching ultra-high sensitivity by per peptide parameter optimization, which allowed for the identification of actionable neoepitopes from sample sizes usually available in the clinic.
2024-08-09 | PXD043542 | Pride
Project description:A major barrier of vaccines as cancer treatment is their failure to activate and maintain a complete cancer-specific CD8+ effector T cell repertoire. Low avidity T cells are more likely to escape clonal deletion in the thymus when compared to higher avidity T cells, and therefore comprise the major population of effector T cells available for activation in cancer patients. However, low avidity T cells fail to traffic into the tumor microenvironment and function in eradicating tumor under optimal vaccination conditions as opposed to higher avidity T cells that escape clonal deletion and do function in tumor killing. We utilized high and low avidity TCR transgenic CD8+ T cells specific for the immunodominant epitope of HER-2/neu (RNEU420-429) to identify signaling pathways responsible for the inferior activity of low avidity T cells. Adoptive transfer of these cells into tumor-bearing vaccinated mice identified members of apoptosis pathways as being upregulated in low avidity T cells. The increased expression of pro-apoptotic proteins by low avidity T cells promoted their own cell death and also that of other tumor-specific CD8+ T cells within their local environment. Importantly, this pro-apoptotic effect was overcome using a strong costimulatory signal that prevents activation-induced cell death and enables low avidity T cells to traffic into the tumor and assist in tumor clearance. These findings identify new therapeutic opportunities for activating the most potent anticancer T cell responses.
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Project description:Strategies for maximizing the potency and specificity of cancer immunotherapies have sparked efforts to identify recurrent epitopes presented in the context of defined tumor-associated neoantigens. Discovering these neoepitopes can be difficult owing to the limited number of peptides that arise from a single point mutation, a low number of copies presented on the cell surface, and variable binding specificity of the human leukocyte antigen (HLA) class I complex. Due to these limitations, many discovery efforts focus on identifying neoepitopes from a small number of cancer neoantigens in the context of few HLA alleles. Here we describe a systematic workflow to characterize binding and presentation of neoepitopes derived from 47 shared cancer neoantigens in the context of 15 HLA alleles. Through the development of a high-throughput neoepitope-HLA binding assay, we surveyed 24,149 candidate neoepitope-HLA combinations resulting in 587 stable complexes. These data were supplemented by computational prediction that identified an additional 257 neoepitope-HLA pairs, resulting in a total of 844 unique combinations. We used these results to build sensitive targeted mass spectrometry assays to validate neoepitope presentation on a panel of HLA-I monoallelic cell lines engineered to express neoantigens of interest as a single polypeptide. Altogether, our analyses detected 84 unique neoepitope-HLA pairs derived from 37 shared cancer neoantigens and presented across 12 HLA alleles. We subsequently identified multiple TCRs which specifically recognized two of these neoantigen-HLA combinations. Finally, these novel TCRs were utilized to elicit a T cell response suggesting that these neoepitopes are likely to be immunogenic. Together these data represent a validated, extensive resource of therapeutically relevant neoepitopes and the HLA context in which they can be targeted.
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Project description:The avidity of the T-cell receptor (TCR) for antigenic peptides presented by the MHC (pMHC) on cells is an essential parameter for efficient T cell-mediated immunity. Yet, whether the TCR-ligand avidity can drive the clonal evolution of virus antigen-specific CD8 T cells, and how this process is determined in latent Cytomegalovirus (CMV)- against Epstein-Barr virus (EBV)-mediated infection remains largely unknown. Here, we quantified monomeric TCR-pMHC dissociation rates on CMV- and EBV-specific individual TCR-alpha-beta clonotypes and polyclonal CD8 T cell populations in healthy donors over a follow-up time of 15-18 years. Within CMV/pp65-specific T cell repertoires, a progressive contraction of clonotypes with high TCR-pMHC avidity and low CD8 binding dependency was observed, leading to an overall avidity decline during long-term antigen exposure. We identified a unique transcriptional signature preferentially expressed by high-avidity CMV/pp65-specific T cell clonotypes, including the inhibitory receptor LILRB1. Interestingly, T cell clonotypes of high-avidity showed higher LILRB1 expression than the low-avidity ones and LILRB1 blockade moderately increased T cell proliferation. Similar findings were made for CD8 T cell repertoires specific for the CMV/IE-1 epitope. There was a gradual in vivo loss of high-avidity T cells with time for both CMV specificities, corresponding to virus-specific CD8 T cells expressing enhanced LILRB1 levels. In sharp contrast, the EBV/BMFL1-specific T cell clonal composition and distribution, once established, displayed an exceptional stability, unrelated to TCR-pMHC binding avidity or LILRB1 expression. Together, these findings reveal an overall long-term avidity decline of CMV- but not EBV-specific T cell clonal repertoires, highlighting the differing role played by TCR-ligand avidity over the course of these two latent herpesvirus infections. Our data suggest that the inhibitor receptor LILRB1 potentially restricts the clonal expansion of high-avidity CMV-specific T cell clonotypes during latent infection. We propose that the mechanisms regulating the long-term outcome of CMV- and EBV-specific memory CD8 T cell clonotypes in humans are distinct.
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Project description:Cancer is characterized by an accumulation of somatic mutations, of which a significant subset can generate cancer-specific neoepitopes that are recognized by autologous T cells. Neoepitopes are emerging as important targets for cancer immunotherapy, including personalized cancer vaccination strategies. We used whole-exome and RNA sequencing analysis to identify potential neoantigens for a patient with non-small cell lung cancer. Sequencing revealed a low tumor mutational burden: 2,219 sequence variants were identified from the primary tumor, of which 23 were expressed in the transcriptome, involving 18 gene products. We assessed autologous T-cell reactivity to the candidate neoantigens using a long peptide approach and could demonstrate spontaneous T-cell responses to 5/18 (28%) mutated gene variants. Further, analysis of the TCR repertoire of neoantigen-specific CD4+ and CD8+ T cells revealed TCR clonotypes that were expanded in both blood and tumor tissue. In parallel, the 18 gene variants were incorporated into a Modified Vaccinia Ankara-based vaccine, which was evaluated in the transgenic HLA-A*02-restricted HHD mouse model. Following vaccination, de novo T-cell responses were generated to 4/18 (22%) mutated gene variants, of which 2 were also observed in the autologous setting; we determined the MHC restriction of the T-cell responses and used in silico prediction tools to determine the likely neoepitopes. Our study demonstrates the feasibility of efficiently identifying tumor-specific neoantigens that can be targeted by vaccination in tumors with a low mutational burden, and promises successful clinical application, with trials currently underway.
2022-04-27 | GSE179879 | GEO
Project description:Identification of neoepitopes that are effective in cancer therapy is a major challenge in creating cancer vaccines. Here, using an entirely unbiased approach, we have queried all possible neoepitopes in a mouse cancer model and asked which of those are effective in mediating tumor rejection, and independently, in eliciting a measurable CD8 response. This analysis uncovers a new universe of effective anticancer neoepitopes which have strikingly different properties from conventional epitopes and suggests a novel algorithm to predict them. It also reveals that our current methods of prediction discard the majority of true anticancer neoepitopes. These results from a single mouse model have been validated in another, independent mouse cancer model, and are consistent with data with human studies. T cells elicited by the active neoepitopes identified here demonstrate a stem-like early dysfunctional phenotype associated with effective responses against viruses and tumors of transgenic mice. These abundant and novel anticancer neoepitopes can be exploited for generation of personalized human cancer vaccines.
2020-12-15 | GSE162432 | GEO
Project description:The success of cancer immunotherapy depends in part on the strength of antigen recognition by T cells. We characterized the T cell receptor (TCR) functional (antigen sensitivity) and structural (monomeric pMHC-TCR off-rates) avidities of 371 CD8 T cell clones specific for neoantigens, tumor-associated antigens (TAAs) or viral antigens isolated from tumors or blood of patients and healthy subjects. T cells from tumors exhibit stronger functional and structural avidity than their blood counterparts. Relative to TAA, neoantigen-specific T cells are of higher structural avidity and, consistently, are preferentially detected in tumors. Effective tumor infiltration in mice models is associated with high structural avidity and CXCR3 expression. Based on TCRs biophysicochemical properties, we derived and applied an in silico model predicting TCR structural avidity and validated the enrichment in high avidity T cells in patients’ tumors. These observations indicate a direct relationship between neoantigen recognition, T cell functionality and tumor infiltration. These results delineate a rational approach to identify potent T cells for personalized cancer immunotherapy.
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Project description:The success of cancer immunotherapy depends in part on the strength of antigen recognition by T cells. We characterized the T cell receptor (TCR) functional (antigen sensitivity) and structural (monomeric pMHC-TCR off-rates) avidities of 371 CD8 T cell clones specific for neoantigens, tumor-associated antigens (TAAs) or viral antigens isolated from tumors or blood of patients and healthy subjects. T cells from tumors exhibit stronger functional and structural avidity than their blood counterparts. Relative to TAA, neoantigen-specific T cells are of higher structural avidity and, consistently, are preferentially detected in tumors. Effective tumor infiltration in mice models is associated with high structural avidity and CXCR3 expression. Based on TCRs biophysicochemical properties, we derived and applied an in silico model predicting TCR structural avidity and validated the enrichment in high avidity T cells in patients’ tumors. These observations indicate a direct relationship between neoantigen recognition, T cell functionality and tumor infiltration. These results delineate a rational approach to identify potent T cells for personalized cancer immunotherapy.
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Project description:This experiment compares the transciptional changes in antigen specific murine CD8 T cells (P14 T cells) after exposure in vivo to dendritic cells (DC) pulsed with low dose cognate peptide (1uM KAVYNFATC), high dose cognate peptide (100uM KAVYNFATC) or no antigen. Splenic dendritic cells were freshly isolated, peptide pulsed, washed and then adoptively transferred s.c. to the right footpad of C57BL/6 hosts. After 18h, freshly isolated P14 CD8 T cells were labelled with CMFDA and adoptively transferred iv. Two hours after T cell transfer, anti-L selectin antibody was given iv. At 12 and 24 hours, recipients were sacrificed and The right popliteal LN was harvested at 12 or 24h post T cell transfer and a single cell suspension was created and stained with PE CD4, B220 and CD19 (dump channel). Cells were then sorted on a FacsARIA for being non-doublets, CMFDA positive and dump channel negative. This experiment compares the transciptional changes in antigen specific murine CD8 T cells (P14 T cells) after exposure in vivo to dendritic cells (DC) pulsed with low dose cognate peptide (1uM KAVYNFATC), high dose cognate peptide (100uM KAVYNFATC) or no antigen. Splenic dendritic cells were freshly isolated, peptide pulsed, washed and then adoptively transferred s.c. to the right footpad of C57BL/6 hosts. After 18h, freshly isolated P14 CD8 T cells were labelled with CMFDA and adoptively transferred iv. Two hours after T cell transfer, anti-L selectin antibody was given iv. At 12 and 24 hours, recipients were sacrificed and The right popliteal LN was harvested at 12 or 24h post T cell transfer and a single cell suspension was created and stained with PE CD4, B220 and CD19 (dump channel). Cells were then sorted on a FacsARIA for being non-doublets, CMFDA positive and dump channel negative. The experiment was conducted for 39 samples out of which 35 passsed transcriptional quality control tests. The phenotypic distribution for the 35 samples includes: (1) high dose (100uM KAVYNFATC ) cognate peptide pulsed samples harvested at 12h post T cell transfer: 6 biological replicates (2) high dose (100uM KAVYNFATC ) cognate peptide pulsed samples harvested at 24h post T cell transfer: 7 biological replicates (3) low dose (1uM KAVYNFATC) cognate peptide pulsed samples harvested at 12h post T cell transfer: 6 biological replicates (4) low dose (1uM KAVYNFATC) cognate peptide pulsed samples harvested at 24h post T cell transfer: 9 biological replicates (5) no antigen pulsed samples harvested at 12h post T cell transfer: 3 biological replicates (6) no antigen pulsed samples harvested at 24h post T cell transfer: 4 biological replicates.
2013-11-21 | E-GEOD-49274 | biostudies-arrayexpress