A branched beta-glucan from Sparassis crispa (SCG) is a major 6-branched 1,3-beta-D-glucan showing antitumor activity. In the present study, we examined the anti-SCG antibody in naive mice by ELISA. Using SCG coated plate, sera of naive DBA/1 and DBA/2 mice contained significantly higher titers of antibody than other strains of mice. Anti-SCG Ab titers of each DBA/1 and DBA/2 mice were significantly varied. Using various polysaccharide-coated plate, sera of DBA/2 mice also reacted with a beta-glucan from Candida spp. (CSBG) having 1,3-beta and 1,6-beta-glucosidic linkages. The SCG specific immunoglobulin (Ig) M but G was detected in sera. The reactivity of sera to coated SCG was neutralized by adding soluble SCG and CSBG as competitor. These results suggested that DBA/1 and DBA/2 strains carry specific and unique immunological characteristics to branched 1,3-/1,6-beta-glucan.