The purpose of this study was to investigate and compare adjuvant effects of soluble beta-glucans from barley and Saccharomyches cerevisia in induction of antigen specific humoral immune responses. Mice were immunized with conalbumin at a relatively low concentration in the presence of beta glucans. Anti-conalbumin antibodies in the sera of immunized and control mice were quantified by ELISA. At high doses, both of glucans increased effectively levels of circulating IgM and IgG antibodies which were specific for conalbumin. However, coadministration of glucan from barley at 1 mu g dose resulted in lower yield in IgG1, IgG2a, IgG2b, and IgA levels in comparison to that of yeast-derived glucan at the same dose. We also found that antigen (conalbumin) specific antibody levels enhanced by beta-glucan from Saccharomyches cerevisia were always higher than those of the glucan from barley. Based on these findings, we concluded that (1,3),( 1,6)-beta-D-glucan from yeast cell wall might have superior immunostimulant activity in induction of antigen specific humoral immune responses over (1,3),( 1,4)- beta-D-glucan from barley.