Suppressive Effect of Wild Saccharomyces cerevisiae and Saccharomyces paradoxus Strains on Ige Production by Mouse Spleen Cells

The genus Saccharomyces includes industrial yeasts that are used for bread and alcoholic beverage production. Saccharomyces strains isolated from natural resources, referred to as "wild" yeasts, are used for making products with strain-specific flavors that are different from those of the "domesticated" industrial yeasts. The physiological effects of wild yeast are poorly understood. In this study, we isolated 2 Saccharomyces cerevisiae strains (S02 - 03) and 5 Saccharomyces paradoxus strains (P01 - 02, S01, S04 - 05) from natural resources in the Kiso area and investigated the effect of these fungal strains on IgE production by mouse spleen cells. Culturing spleen cells with heat-killed yeasts resulted in elevated IFN-gamma and IL-12 levels followed by significant reduction in IgE levels. The S03 and P01 strains induced IL-12 p40 and IL-10 expression in RAW264 cells. Thus, wild strains of S. cerevisiae and S. paradoxus regulate macrophage cytokine production to improve the Th1/Th2 immune balance and suppress IgE production.