The Effects Of Oral Administration Of Aureobasidium Pullulans-Cultured Fluid Containing Beta-Glucan On Concanavalin A Injected Mice

A black yeast, Aureobasidium pullulans, extracellularly produces beta-(1,3), (1,6)-D-glucan (beta-glucan) under certain conditions. The beta-glucan is known to be an immunomodulatory agent, and beta-glucan enriched A. pullulans cultured fluid (AP-CF) is used in supplements to maintain human health. Concanavalin A (ConA) is a lectin, and when injected it is known to cause T cell mediated autoimmune hepatitis in mice. The present study investigated the effects of oral administration of AP-CF on ConA injection in mice. The results demonstrated that increases in serum alanine transaminase (ALT) levels after ConA injection were significantly suppressed in an AP-CF administered group of mice. To understand the mechanism of the ALT lowering effects of AP-CF, we used Foxp3 (forkhead box P3) knock-in mice which express the green fluorescent protein (GFP) in Foxp3 induced cells, and the effects of AP-CF on the regulatory T cell (T-reg) populations were investigated. The results show that the basal level of Foxp3(+) T-reg populations in peripheral blood lymphocytes, liver infiltrating lymphocytes, and splenocytes was decreased after 7 days of administration of AP-CF. These findings suggest that oral administration of AP-CF suppresses the basal level of inflammation, and that it may be postulated to be involved in the ALT lowering effects of AP-CF.