Also, to exclude the impacts of EL4 exosomes on the cytotoxicity of OT-I CTLs and the vitality of tumor cells, we tested the proliferation and cytotoxic cytokine production of OT-I cells, including IFN-γ, granzyme B, perforin, and TNF-α (Supplementary Fig. 3A, B), and no significance changes were found. Here, PRF1 is linked to neoplasm.