The Cd4+ T cell population Partners with Tpex CD8 T cells to mediate Antitumor Immunity in the Tumor Microenvironment.[P5]

The priming, expansion, and function of CD8? T cells are helped by CD4? T cells via dendritic cells. Precursor exhausted T cells (Tpex) maintain self-renewal and supply cytotoxic CD8? T cells in the tumor microenvironment (TME), but the identity of their CD4? T-cell partners remains unclear. Here, we perform scRNA-seq, scTCR-seq, and mass cytometry analysis on peripheral blood, tumor, and lymph nodes derived from lung cancer patients and identify a population of IL-7Rhigh CCR6? Th1-like CD4? T cells, namedTh7R, that is numerically and spatially partnered with Tpex cells. Th7R cells express lymphotoxin-ß and CXCL13, correlate with high endothelial venules, and co-localize with Tpex in tertiary lymphoid structures. Furthermore, Th7R cell abundance correlates with Tpex numbers in the TME and lymph nodes, and adoptive transfer of Th7R increases Tpex in a preclinical mouse model of skin cancer. In lung cancer patients, Th7R and Tpex in TME are associated with better response to neoadjuvant PD-1 blockade therapy. Thus, these results suggest that Th7R cells act as partners of Tpex CD8 T cells to sustain antitumor T-cell immunity. Overall design: This study investigates the relationship between CD4+ and CD8+ T cells in tumor-infiltrating lymphocytes (TILs) and peripheral blood mononuclear cells (PBMCs). Single-cell RNA sequencing, TCR repertoire profiling, and surface protein expression analysis were performed using the 10x Genomics Chromium Next GEM Single Cell 5' Reagent Kits v2. Matched TIL and PBMC samples were collected from each individual. Gene expression (GEX), TCR (V(D)J), and antibody-derived tag (ADT) libraries were generated from the same cells, enabling integrated analysis of transcriptomes, clonotypes, and surface markers to compare T cell phenotypes and clonal structures across compartments.