Inonotus obliquus extracts suppress antigen-specific IgE production through the modulation of Th1/Th2 cytokines in ovalbumin-sensitized mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Chaga mushroom (Inonotus obliquus, IO) has been used as a folk remedy for cancer, digestive system diseases, and other illnesses in Russia and Eastern Europe.

AIM OF THE STUDY: In the present study, we investigated the immunomodulating effects of IO through in vivo and ex vivo studies.

MATERIALS AND METHODS: Serum immunoglobulins (IgE, IgG(1), and IgG(2a)) and cytokines (interleukin (IL)-4, interferon (IFN)-γ, and IL-2) were measured in concanavalin A (ConA)-stimulated splenocytes and CD4(+) T cells. The nitric oxide (NO) secretion of lipopolysaccharide (LPS)-stimulated peritoneal macrophages was also measured after oral administration of 50, 100, or 200 mg kg(-1) d(-1) IO hot water extract (IOE) to ovalbumin (OVA)-sensitized BALB/c mice.

RESULTS: We found that the OVA-induced increase in serum IgE and IgG(2a) was significantly suppressed when IOE was orally administered after the second immunization with OVA. ConA stimulation in spleen cells isolated from OVA-sensitized mice treated with 100 mg kg(-1) IOE resulted in a 25.2% decrease in IL-4 production and a 102.4% increase in IFN-γ, compared to the controls. Moreover, IL-4, IFN-γ, and IL-2 were significantly reduced after ConA stimulation in isolated CD4(+)T cells. We also determined that IOE inhibits the secretion of NO from LPS-stimulated peritoneal macrophages ex vivo.

CONCLUSIONS: We suggest that IO modulates immune responses through secretion of Th1/Th2 cytokines in immune cells and regulates antigen-specific antibody production.