Oxygen radical production by peritoneal macrophages and Kupffer cells elicited with Lactobacillus casei.

BALB/c mice were injected intraperitoneally (i.p.) or intravenously (i.v.) with Lactobacillus casei YIT9018 (LC 9018). The i.p. injected LC 9018 augmented oxygen radical (OR) production by peritoneal macrophages (PM) and suppressed the production of prostaglandin E2 by PM. The growth of i.p. inoculated Meth A fibrosarcoma was also inhibited by an i.p. injection of LC 9018. i.v. injection of LC 9018 stimulated OR production by fixed macrophages and inhibited the growth of Listeria monocytogenes in the liver. Furthermore, glucose-6-phosphate dehydrogenase activity in the liver was significantly increased (10 to 20 times) by LC 9018 i.v. injection. A significant correlation was observed between the augmentation of OR production by PM or fixed macrophages in the liver and inhibition of growth of Meth A or L. monocytogenes. The augmentation of OR production by LC 9018 was more marked and was maintained for a longer period of time than that by other bacterial immunostimulants.