Immunomodulatory effect of β-glucan derived from Saccharomyces cerevisiae strains

The aim of this study was to evaluate immunopotentiating activities of β-glucan derived from Saccharomyces (S.) cerevisiae and to select new strains having possibility as an immune-enhancing substance. We examined SB20 strains derived from commercial product as a control, and extracted β-glucans from the four strains of S. cerevisiae. RAW264.7 macrophages were treated with heat-killed yeasts, β-glucans, and lipopolysaccharide (LPS). The production of nitric oxide (NO) and cytokines such as TNF-α and IL-1β were then quantified. When macrophages were induced directly by in vitro addition of β-glucan, little production of NO and IL-1β was observed. When pretreated with strong stimulants, i.e., LPS, most yeasts showed down-modulation of NO and IL-1β production. However, TNF-α secretion was triggered by β-glucans and even more increased by the mixture effect of LPS and β-glucans. In particular, S6 strain induced TNF-α secretion more than other strains. Therefore, we can conclude that the S6 strain has possibility as an immune-enhancing substance.