PARTIAL-PURIFICATION AND CHARACTERIZATION OF MOLD ANTIGENS COMMONLY FOUND IN FOODS

Rapid methods are needed for detection of molds in foods; therefore, a n enzyme-linked immunosorbent assay was developed. The extracellular a nd mycelial antigens for Mucor, Aspergillus, Cladosporium, and Geotric hum species were partially purified and characterized. The molecular m asses of the mycelial and extracellular antigens, as determined by siz e exclusion chromatography, ranged from 4.5 x 10(5) to 6.7 x 10(5) Da. There was only one main antigenic peak separated by Sepharose CL-4B a nd concanavalin A-Sepharose columns for Mucor, Cladosporium, and Geotr ichum mycelial and extracellular antigens, but there were two for Aspe rgillus mycelial antigens and three for Aspergillus extracellular anti gens. These antigens contained 10 to 50% protein which was part of the active site since protease digestion significantly decreased antigeni c activity. Neutral sugars, ranging from 13 to 75%, made up the rest o f the active site, and <1% phosphate was detected in mycelial antigens . Geotrichum, Cladosporium, and Aspergillus antigens contained mainly glucose, galactose, and mannose. Mucor antigens contained these sugars plus fucose. The percentage of sugars differed between the mycelia an d extracellular antigens. Enzymatic digestion and competitive inhibiti on tests using different sugar derivatives showed that galactosyl resi dues with 13 linkages were immunodominant for Aspergillus, Geotrichum, and Cladosporium antigens and mannosyl residues with alpha linkages w ere immunodominant for Mucor antigens.