[Cytotoxic effect of BCG-activated macrophages on tumor target cells in vitro]

The macrophage-activating effect of fluid and lyophilized BCG vaccines and killed BCG was studied. Activation of murine peritoneal macrophages was determined by their cytotoxic action in vitro on the syngeneic tumour 51Cr-labeled target cells. Murine macrophages obtained 2 to 3 weeks after a single injection of the fluid BCG vaccine exerted a cytotoxic action on the tumour cells. A single injection of the lyophilized BCG vaccine or killed BCG caused no macrophage activation. Two injections of fluid or lyophilized BCG vaccines caused macrophage activation earlier--3 to 5 days after the second injection. Intraperitoneal BCG injection induced more macrophage activation than subcutaneous.