Basidiospore allergens: analysis of Coprinus quadrifidus spore, cap, and stalk extracts

Atopic individuals with symptoms of respiratory allergy have been shown to have IgE-mediated reactions to spores from the basidiomycete fungi. Because our earlier studies suggested that parts of the fungus other than spores may contain allergens, the current study was performed. Extracts of Coprinus quadrifidus spores, caps, and stalks were prepared and fractionated by gel filtration column chromatography on Sephadex G-75. Analysis of column fractions of each separation by ultraviolet absorption demonstrated at least three peaks of absorbency in spore, cap, and stalk extracts. Pooled column fractions were analysed by direct radio-allergosorbent test (RAST) using pooled sera from C. quadrifidus skin-test positive subjects. Enhanced allergenic activity was present in the same portion of the column eluate for cap, spore, and stalk fractionations, corresponding to a molecular weight of approximately 10.5–25 kD. Pools with allergenic activity were used to test volunteers by skin prick and RAST. Skin test and RAST activities were similar for each of the three Coprinus extracts, with stalk being the most potent. Evidence of common allergenic epitopes was demonstrated by inhibition of spore RAST by spore, cap, and stalk extracts. These results suggest that C. quadrifidus cap and stalk extracts contain allergens similar to those in spores extract and may provide useful sources of allergen for further study.