Transcriptional programming of tumor-specific conventional CD4+ T cells in resectable non-small cell lung cancer 9240

Abstract Description The role of tumor-reactive CD8+ T cells in mediating clinical response to immune checkpoint blockade (ICB) has been well-described. However, the role of tumor-reactive conventional CD4+ T cells (Tconv) remains relatively unexplored, in part because identification of these cells is challenging. To address this, we compared two orthogonal approaches. The first approach applied a 3-gene signature (MANAscore) that we previously developed and demonstrated to accurately identify CD8+ tumor-reactive TIL. Second, we transcriptionally profiled adoptively transferred TCR-transgenic tumor-reactive CD4+ T cells in a murine tumor model to develop a gene signature for these cells. We then applied both signatures to single cell data from human lung cancer TIL treated with neoadjuvant PD-1 blockade to identify putative tumor-reactive cells (pTRC). Roughly 70% of pTRC identified by MANAscore were also identified by the murine signature. There was a lower frequency of CD4+ pTRC in non-responding relative to responding tumors. The majority of pTRC localized to a CXCL13hi cluster enriched in the tumor relative to adjacent normal tissue and was characterized by high expression of GZMA, GZMB, GZMH, CXCR6, CCL4, CCL5, and downregulation of CXCR5. These transcriptional features distinguished this CXCL13hi cluster from both canonical Th1 and Tfh cells. Ongoing work will further elucidate the functions of Tconv pTRC in the TME and the impact of ICB on their transcriptional programming in lung cancer. Funding Sources Supported by NIH R37 CA251447; American Lung Association; Swim Across America; Mark Foundation for Cancer Research Topic Categories Tumor Immunology: Checkpoints, Prevention, and Treatment (TIPT)