KLRC1 and neoplasm: Although NKG2A is primarily expressed on NK cells, it is also detected on CD8 + T cells within the tumor environment.28 Consistently, sorted populations of CD3 + opT cells retained the ability to respond to NKG2A blockade (online supplemental figure S2D, E), demonstrating that NKG2A regulates cytotoxic T cell activity of Pt3 opT cells.