Characterization of CD103 CD8 tissue-resident T cells in esophageal squamous cell carcinoma: may be tumor reactive and resurrected by anti-PD-1 blockade.

Though therapy that promotes anti-tumor response about CD8 tumor-infiltrating lymphocytes (TILs) has shown great potential, clinical responses to CD8 TILs immunotherapy vary considerably, largely because of different subpopulation of CD8 TILs exhibiting different biological characters. To define the relationship between subpopulation of CD8 TILs and the outcome of antitumor reaction, the phenotype and function of CD103 CD8 TILs in esophageal squamous cell carcinoma (ESCC) were investigated. CD103 CD8 TILs were presented in ESCC, which displayed phenotype of tissue-resident memory T cells and exhibited high expression of immune checkpoints (PD-1, TIM-3). CD103 CD8 TILs were positively associated with the overall survivals of ESCC patients. This population of cells elicited potent proliferation and cytotoxic cytokine secretion potential. In addition, CD103 CD8 TILs were elicited potent anti-tumor immunity after anti-PD-1 blockade and were not affected by chemotherapy. This study emphasized the feature of CD103 CD8 TILs in immune response and identified potentially new targets in ESCC patients.