Modulation of cytokine and immunogloblin a release by beta-(1,3-1,6)-glucan from aureobasidium pullulans strain 1A1

Abstract

Beta-glucan, derived from mushroom or yeast extracts, is well known for its various immunopharmacological effects such as anti-microbial properties and anti-tumor activities for host defense. We isolated beta-glucans (DS-PG), secreted by the fungus body, from the culture medium of Aureobasidium pullulans strain 1A1. DS-beta G form soluble microparticles and we prepared DS-beta G to 85-95% purity. The structure of DS-beta G is based on a backbone of beta-(1,3)-linked beta-D-glucopyranosyl units, with beta-(1,6) linked side-chains of varying distribution. Their molecular weight range is 50,000-300,000, with the average estimated to be 100,000. In this study, we investigated the immunomodulatory effects of DS-beta G, especially its in vitro and in vivo effects on the intestinal immune system. Peyer's patches (PP) cells from BALB/cA mice were cultured with DS-beta G (0 similar to 200 mu g/ml) and IgA and cytokine levels in culture supernatant measured by ELISA. The addition of DS-beta G induced IgA production in a dose-dependent manner. Both the levels of interleukin-5 (IL-5) and interleukin-6 (IL-6), cytokines known to enhance IgA production, were also elevated. Oral administration of DS-beta G (400 rho g/mouse/day) for 7 consecutive days induced IgA production by PP cells. These results demonstrate that DS-beta G acts on the gut immune system and increase IgA production that is vitally important for defense against infection.