IMMUNOLOGICAL AND CHEMICAL CHARACTERIZATION OF GLYCOPROTEINS IN IEF FRACTIONS OF BLASTOMYCES-DERMATITIDIS YEAST LYSATE ANTIGEN

After isoelectric focusing (IEF), fractions of a Blastomyces dermatiti dis yeast lysate antigen were analysed for the presence of glycoprotei ns that may lead to cross-reactivity in immunoassays for the diagnosis of blastomycosis. Five major glycoproteins were apparent, two of whic h showed cross-reactivity when used in Western blots with sera obtaine d from dogs with histoplasmosis and coccidioidomycosis. These five gly coproteins were characterized for linkage to the proteins using N-glyc osidase F (NGF) and for their lectin binding properties. The cross-rea ctive 235- and 160-kDa glycoproteins were found to possess mainly O-li nked, high-mannose-type carbohydrates, and periodate-mediated oxidatio n of these molecules eliminated cross-reactivity observed with heterol ogous sera. Thus, the periodate-treated IEF antigens described here ma y be useful in solid-phase enzyme immunoassays for the diagnosis of bl astomycosis.