Administration of a Polysaccharide from Grifola frondosa Stimulates Immune Function of Normal Mice

We have reported that D-Fraction, a polysaccharide extracted from the edible maitake mushroom (Grifola frondosa), activates immunocompetent cells, thereby eliciting antitumor activity. To extend the application of D-Fraction as a nutritional supplement for healthy people as well as treatment for those with cancer, we investigated the effects of D-Fraction on the immune system in normal C3H/HeJ mice. Splenocytes from mice administered D-Fraction intraperitoneally for 17 consecutive days were cultured, and the culture supernatants were analyzed for nitric oxide (NO) and interleukin (IL)-12 production by antigen-presenting cells (APCs), including macrophages and dendritic cells, and also for the T helper (Th)-1 cytokine interferon (IFN)-γ and the Th-2 cytokines IL-4 and IL-10. The level of IL-10 as well as those of NO and IFN-γ were increased by D-Fraction as compared with the control, in which the serum immunoglobulin E level was increased. The results suggest that D-Fraction induced a Th-2 dominant respons...