PRF1 and cancer: Of note, both CD8+ T.eff and CD4+ TH1 cells exhibited high expression of effector molecules or cytokines, such as Gzma, Ifng, Prf1, and Lck (Fig. 4C), and costimulatory molecules (Rgs16 and Tnfrsf9), indicating that MHC-I and MHC-II neoepitopes involved in cancer vaccine elicited robust CD8+ and CD4+ T cell responses.