Cisplatin modulates tumor cell susceptibility to tumor-infiltrating lymphocytes in vivo

We investigated the in vivo augmentation of susceptibility of tumor cells to tumor-infiltrating lymphocytes (TILs) with cisplatin (CDDP). TILs showed cytotoxicity against autologous and established tumor cells. Pretreatment of tumor cells with CDDP 2 mu g/ml for 12 h enhanced the susceptibility of tumor cells to TILs in vitro. TILs and autologous tumor cells were obtained from malignant ascites of patients, before and after the intraperitoneal administration of CDDP. TILs had higher cytotoxicity against autologous tumor cells of CDDP treated as compared to untreated control tumor cells, providing direct evidence of in vivo immunomodulatory effect of CDDP in cancer patients.