Cellular microcytotoxicity in a human bladder cancer system: analysis of in vitro lymphocyte-mediated cytotoxicity against cultured target cells

The microcytotoxicity test (MCT) has been used to determine the cytotoxic effects of purified peripheral blood lymphocytes from patients with carcinoma of the urinary bladder (BT), tumor control patients (TC) (tested after therapy), and healthy donors (HD) against cultured bladder tumor cells, melanoma cells, and normal bladder cells. Lymphocytes from all three donor groups were tested in parallel. Disease-specific cytotoxicity (CTX) is defined as statistically significant and selective destruction of disease-related tumor target cells by the test lymphocytes in comparison with the baseline controls. Nonspecific CTX is defined as statistically significant destruction of a proportion (selective) or all (nonselective) disease unrelated target cells by the effector cells. Within the different donor groups, an enormous variation in non-disease related cytotoxic effects against the different cell lines was seen. It appeared that the selection of the baseline control influences the level of CTX and the specificity of the reaction. In order to determine whether a disease-specific cytotoxic effect was superimposed on the nonspecific cytotoxicity, the overall cytotoxic effects of the lymphocytes from the BT, TC patients and HD were compared statistically. The analysis of results revealed that effector cells from BT, TC patients and HD showed the same pattern of reactivity, but the CTX of lymphocytes from BT patients tested before therapy was stronger in comparison with the CTX of lymphocytes from the same group of BT patients after therapy and in comparison with the CTX of lymphocytes from HD and TC patients.