Production of interleukin-1 activity of Kupffer cells from mice treated with the acidic mannan fraction of baker's yeast.

We investigated the production of interleukin-1 (IL-1) activity by Kupffer cells (KC) from mice treated with a neutral mannan fraction (WNM) or an acidic mannan fraction (WAM025) from baker's yeast (Saccharomyces cerevisiae) in vivo and in vitro. The mice administered WAM025 showed an increase in the number of KC and the IL-1 production compared with mice administered WNM. In an in vitro stimulation assay using KC from a normal mouse, it was also found that WAM025 displayed an increase in IL-1 production. Diisopropyl fluorophosphate completely inhibited the production of IL-1 by KC from the mice administered WAM025.