Transcriptomic profiling of immune and stromal cells from the non small cell lung cancer (NSCLC) environment

T lymphocytes can efficiently counteract the growth of tumors within the tumor microenvironment. Specialized immune-interacting fibroblasts, termed fibroblastic reticular cells (FRC) are responsible for the formation of specialized niches promoting immune cell activation in secondary lymphoid organs and originate from embryonic progenitors. FRCs have also been identified in tertiary lymphoid structures (TLS) in tumor tissues. However, the identity and differentiation of TLS-associated FRC subsets that promote intra-tumoral T cell activity have remained unexplored. Here, we employed single cell RNA-sequencing of fibroblasts and immune cells, sampled from subpleural margin, central margin and unaffected lung tissue in non small cell lung cancer (NSCLC), demonstrating the formation of specific tumor T cell environments (TTEs) underpinned by CCL19-expressing FRCs. We detected tumor-specific FRC subsets namely CCL19-expressing TRCs and perivascular reticular cells (PRCs) interacting with intratumoral T cells, and thus regulating FRC differentiation and T cell activation. Our results highlight a remarkable functionality of FRCs to efficiently determine protective antitumoral T cell responses in NSCLC.