CD103CD8 T lymphocytes in non-small cell lung cancer are phenotypically and functionally primed to respond to PD-1 blockade.

CD103CD8 tumor infiltrating lymphocytes (TILs) have been linked to prolonged survival in various types of cancer including non-small cell lung cancer (NSCLC). However, the factors associated with the retention of CD103CD8 TILs in lung cancer tissues remain largely unknown. Additionally, the contribution of CD103CD8 TILs to effective PD-1 based immunotherapy has not been fully elucidated. In this study, we identified that the expression levels of E-cadherin and TGF-β were significantly correlated with the distribution and the density of CD103 TILs in lung cancer tumor tissues. Unexpectedly, we observed that CD103CD8 TILs that expressed higher levels of PD-1 co-express Ki-67. Moreover, CD103CD8 TILs expressed an increased level of T-bet compared to their counterparts, indicating these cells may be better armed for immunotherapy. Lastly, PD-1 pathway blockade led to a significantly increased production of IFN-γ by CD103CD8 TILs, suggesting CD103CD8 TILs could serve as a predictive biomarker for PD-1 based immunotherapy.