Intratumoral CD4+ T Cells Mediate Anti-tumor Cytotoxicity in Human Bladder Cancer

Summary Responses to anti-PD-1 immunotherapy occur but are infrequent in bladder cancer. The specific T cells that mediate tumor rejection are unknown. T cells from human bladder tumors and non-malignant tissue were assessed with single-cell RNA and paired T cell receptor (TCR) sequencing of 30,604 T cells from 7 patients. We find that the states and repertoires of CD8+ T cells are not distinct in tumors compared with non-malignant tissues. In contrast, single-cell analysis of CD4+ T cells demonstrates several tumor-specific states, including multiple distinct states of regulatory T cells. Surprisingly, we also find multiple cytotoxic CD4+ T cell states that are clonally expanded. These CD4+ T cells can kill autologous tumors in an MHC class II-dependent fashion and are suppressed by regulatory T cells. Further, a gene signature of cytotoxic CD4+ T cells in tumors predicts a clinical response in 244 metastatic bladder cancer patients treated with anti-PD-L1.
Graphical Abstract
Highlights • Human bladder tumors contain multiple clonally expanded cytotoxic CD4+ T cell states • Cytotoxic CD4+ T cells can kill autologous tumors in an MHC class II-dependent fashion • Autologous regulatory T cells can inhibit the activity of cytotoxic CD4+ T cells • A cytotoxic CD4+ gene signature predicts response to anti-PD-L1 in bladder cancer
Single-cell RNA and paired T cell receptor sequencing highlights enrichment of cytotoxic CD4+ T cells rather than CD8+ T cells in human bladder cancer. These CD4+ T cells are capable of killing autologous tumor cells and are subjected to inhibition by Tregs.