Solubilized cell wall beta-glucan, CSBG, is an epitope of Candida immune mice

Antibody to beta-glucan is generally difficult to produce in mice. We have recently developed a protocol to obtain a soluble Candida spp. beta-(1-->3)-D-glucan (CSBG) by sodium hypochlorite (NaClO) oxidation and subsequent dimethyl sulfoxide (Me2SO) extraction. CSBG is composed mainly of beta-(1-->3) and beta-(1-->6)-glucosidic linkages with a small amount of branch. In this paper, mice were immunized with Candida albicans and the specificity of the resulting sera to CSBG was examined by ELISA. Using CSBG coated plate, sera of the Candida immune mice showed higher reactivity than non-immune, normal mice and the reactivity was neutralized by adding soluble CSBG as a competitor. However, the reactivity could not be neutralized by a beta-(1-->6) branched beta-(1-->3)-glucan, grifolan. Similar specificity of the sera was obtained by commercially available beta-glucan particle, zymosan or zymocel, immune mice. These facts strongly suggested that CSBG included epitopes of the specific antibody in Candida immune mice.