EFFECT OF BACILLUS-SUBTILIS SPORE ADMINISTRATION ON ACTIVATION OF MACROPHAGES AND NATURAL-KILLER-CELLS IN MICE

The effect of Bacillus subtilis (strain A102) spores on the activation of murine macrophages and natural killer cells (NK) was examined. The macrophage activity and NK activity were enhanced by oral administrat ion of A102 spores, and slightly enhanced by oral administration of cu lture supernatant. There was no difference in the results of macrophag e activity and NK activity using other live or dead spores, The NK act ivity and macrophage activity were increased with increments of concen tration up to 0.1 g per mouse, and both activities were decreased at c oncentration of more than 0.15 g per mouse. The NK activity was increa sed 1 and 2 days after oral administration of A102 spores, and the act ivity level 2 days after administration was about 3-fold higher than t he level prior to treatment. Macrophage activity was also increased fr om 1 to 3 days after oral administration of A102 spores, and the activ ity level 3 days after administration was about 3-fold higher than the level prior to treatment. The induction of interferons at 1 day after oral administration in mouse serum was 5-fold higher than that in con trols. These findings indicate that oral administration of A102 gave r ise to the induction of interferons, and it is likely that macrophages and NK cells were activated by interferons. (C) 1998 Elsevier Science B.V.