The effects of oral administration of Aureobasidium pullulans -cultured fluid containing β-glucan on concanavalin A injected mice.

A black yeast, Aureobasidium pullulans , extracellularly produces β-(1,3), (1,6)-D-glucan (β-glucan) under certain conditions. The β-glucan is known to be an immunomodulatory agent, and β-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.
Competing Interests: The authors declare the following conflict of interests: Atsushi Iwai and Kisato Kusano are employees of Aureo Co., Ltd., and β-glucan-containing Aureobasidium pullulans-cultured fluid and its derivatives are marketed by Aureo Co., Ltd.
(© 2021 The Author(s).)