BACILLUS-CALMETTE-GUERIN (BCG) ENHANCES MONOCYTE-MEDIATED AND LYMPHOCYTE-MEDIATED BLADDER-TUMOR CELL-KILLING

A cytotoxicity assay was used to study the action of bacillus Calmette -Guerin (BCG) and cytokines on four human bladder cancer cell lines. M onocytes and lymphocytes from peripheral blood were incubated with or without BCG or cytokines for 24 h, after which [H-3]thymidine-labelled target cells were added and the 72 h percentage specific release dete rmined. BCG had a direct cytotoxic effect against tumour cells and sig nificantly enhanced monocyte/macrophage and enhanced lymphocyte cytoto xicity against one cell line (UCRU-BL-17). Supernatants (SNs) from BCG -activated monocytes/macrophages and Lymphocytes increased the percent age specific release of [H-3]thymidine from UCRU-BL-17 cells. Interfer on alpha (IFN-alpha) and interleukin 2 (IL-2) were cytotoxic towards U CRU-BL-17. No synergy occurred between BCG and cytokines at the concen trations tested. The results suggest that BCG is superior to IFN-alpha , interferon gamma IFN-gamma and IL-2 in enhancing cell-mediated cytot oxicity.