The specificity of the microcytotoxicity assay for cell-mediated immunity in human bladder cancer

Cytotoxicity of lymphocytes from T1 or T2 bladder cancer patients and patients with other diseases was tested in 44-hour microcytotoxicity assay against 3 different target cell lines: 1) HU 456, derived from human bladder carcinoma and established in our laboratory, 2) HU 609, a line derived from normal human bladder tissue and established in our laboratory and 3) SAOS-2, a human osteosarcoma cell line from the Memorial Sloan-Kettering Cancer Institute. Lymphocyte concentrations ranging from 7.8 time 10(4) to 2.5 times 10(6) lymphocytes per ml. were tested against each cell line. Lymphocytes from both groups of patients demonstrated a cytotoxicity against all 3 target cell lines, proportional to the lymphocyte concentration used. There was no difference in reactivity to HU 609 or to SAOS-2 between bladder cancer and control patients but the lymphocytes of bladder cancer patients showed a statistically greater cytotoxicity for HU 456, demonstrating a tumor type-specific cellular immune reaction superimposed on a background of non-specific cytotoxicity.