Effect of BCG on alloimmune cell-mediated cytotoxicity in (C57BL/6Jfemale x A/Jmale)F1 mice. I. Effect of different BCG treatments on cytotoxicity mediated by T-cells and macrophages.

The effect of BCG on the development of cell-mediated cytotoxicity (CMC) in the spleens of allogeneic tumor-bearing female (C57BL/6Jfemale x A/Jmale)F1 mice was studied. BCG-treated tumor-bearing animals elicited a stronger CMC response than did the untreated tumor-bearing animals. Furthermore, the degree of activation was dependent on the time, route of injection, and dose of BCG. Therefore, if the BCG was administered at suboptimal conditions, a less marked stimulation of the CMC resulted. A combination of a high BCG dose given iv 12 days before implant of P815 tumor cells and a low, second dose given at the time of implant produced the most marked activation of the CMC response. By the use of in vitro technique, the specific CMC was mediated mostly by T-cells, with macrophages making a less significant contribution.