Single-cell landscape of tumor-infiltrating T cells in renal cell carcinoma reveals novel insights into double-positive/double-negative T cells 2441

Abstract Description Renal cell carcinoma (RCC) patients exhibit variable responses to immune checkpoint blockade therapies. Identifying reliable biomarkers to predict response remains a critical challenge. Tumor-infiltrating T cells (TILs) are implicated in immunotherapy outcomes, but their phenotypic diversity and spatial distribution within the tumor microenvironment are poorly understood. In this study, we performed multi-omic profiling of matched tumor, adjacent normal kidney, and peripheral blood samples with high-resolution spatial transcriptomics was conducted on formalin-fixed paraffin-embedded samples. We identified distinct subsets of CD4+CD8+ double-positive (DP) and CD4-CD8- double-negative (DN) T cells, each with unique gene expression signatures and TCR repertoires. DP T cells exhibited an exhausted phenotype, marked by co-inhibitory receptor expression and clonal TCR expansion, suggesting chronic antigen exposure. DN T cells displayed a heterogeneous profile, expressing both cytotoxic and regulatory molecules, alongside with diverse TCR repertoires, indicating potential tumor-specific reactivity. Spatial transcriptomics revealed distinct localization patterns of DP and DN T cells within the tumor microenvironment. This study provides a comprehensive analysis of TILs in RCC, highlighting the heterogeneity and functional specialization of DP and DN T cells. Funding Sources Supported by Sungkyunkwan University Start-up Fund 2024-1239-000-1; National Research Foundation of Korea RS-2024-00405650 Topic Categories Tumor Immunology: Cellular Responses and Tumor Microevironment (TIME)