Antitumor activity of peritoneal exudate cells induced by cell-wall skeleton of Mycobacterium bovis BCG.

Peritoneal exudate cells (PEC) induced by oil-attached cell-wall skeleton of Mycobacterium bovis BCG (BCG-CWS) in ACI/N rats were tested for their effect on both in vivo and in vitro growth of syngeneic fibrosarcoma cells (AMC-60). Treatment of rats with intraperitoneal injections of BCG-CWS induced regression of syngeneic ascites tumor and increased the number of survivals. Whole PEC and adherent PEC from rats injected intraperitoneally with BCG-CWS inhibited the uptake of tritiated thymidine into the fibrosarcoma cells in an in vitro cytostasis test. This in vitro cytostatic effect was more marked as the ratio of effector to target cells increased. In addition, when tumor cells were inoculated subcutaneously with BCG-CWS activated PEC, tumor takes decreased markedly. Oil-stimulated PEC and normal peritoneal resident cells were inactive in inhibition of tumor growth in vivo and in vitro.