Solubilized candida cell Wall β‐glucan, CSBG, is an epitope of natural human antibody

Abstract
We have recently developed a protocol to obtain a soluble Candida spp. β1, 3‐glucan (CSBG) by sodium hypochlorite (NaClO) oxidation and subsequent dimethyl sulfoxide (DMSO) extraction. CSBG is composed mainly of β‐1,3 and β‐1,6‐glucosidic linkages with a small amount of branching. Antibody to β‐glucan is generally difficult to produce. In the present study, the specificity of the human sera to CSBG was examined by ELISA. Using CSBG‐coated plates, sera from normal human volunteers showed high reactivity that was neutralized by adding soluble CSBG as a competitor. However, the reactivity could not be neutralized by a β‐1,6 branched β‐1,3‐glucan, grifolan. Similar specificity of the immunoglobulin (Ig) was detected in commercially available γ‐globulin prepared from pooled human sera. Comparing various standard glucans, a major epitope was present on β‐1,6 glucan segment. Drug Dev. Res. 58:179–189, 2003.