In vitro cytolysis of MM46 tumor cells by mouse phagocytes activated by acidic mannan fraction of bakers' yeast.

An acidic mannan from bakers' yeast designated as WAM025 was investigated for its augmentative effect on cytolytic activity of phagocytes obtained from the peritoneal cavity of C3H/He strain mice, which had been administered i.p. with this acidic polysaccharide, 150 mg/kg/d, 5 and 10 times. The result of assay for the cytolytic effect of WAM025-activated phagocytes by measuring the amounts of 3H-uridine of the MM46 tumor cells indicated that a marked lysis of the target cells took place by a 24-h incubation with the activated phagocytes and that a decrease of this effect was observed by the additions of either phagocytic inhibitors or active oxygen scavengers. Because generation of active oxygens from the WAM025-activated phagocytes was also diminished by the additions of the same inhibitors and scavengers, it indicated that active oxygens participated in an important role in the cytolytic effect displayed by the WAM025-activated phagocytes.