Characterization of cell-mediated cytolytic mechanisms against human transitional cell carcinoma line, 253J

We examined the nature of effector cells that mediate antibody-dependent cell-mediated cytotoxicity (ADCC) and spontaneous cell-mediated cytotoxicity (SCMC) against the 253J human bladder transitional cell carcinoma cell line. Fractionation of peripheral blood lymphocytes (PBL) showed that ADCC and SCMC against the 253J targets were mediated by non-adherent, surface immunoglobulin-negative lymphocytes lacking or having only weak affinity for sheep erythrocytes. Macrophages were not cytotoxic against 253J cells in 18 h culture, as removal of macrophages by glass adherence or treatment with silica particles did not reduce ADCC or SCMC, and macrophage-enriched effector cell preparations were only weakly cytotoxic.