Basidiomycete allergens: comparison of three Ganoderma species

Abstract

High atmospheric concentrations of basidiospores occur in various parts of the world. Ganoderma basidiospores are distinctive, easily identifiable in aeroallergen surveys, and widely abundant. Previous studies showed that Ganoderma basidiospores caused respiratory allergies. Thus, we investigated various extracts (spore, cap, and/or mycelial) of G. meredithae, G. lucidum, and G. applanatum for allergen components. Analyses included radioallergosorbent test (RAST) inhibition and IgE blots from isoelectric focusing (IEF) and SDS-PAGE. RAST inhibition with spores and caps of G. meredithae and G. lucidum showed that spores inhibited caps better than caps inhibited spores. Species differences were minor. Coomassie blue (CB) staining of IEF gels detected at least 23 protein bands (pI 3.6-6.6) in caps of G. meredithae and G. lucidum. G. meredithae spore extracts contained 17 of these (pI 3.6-5.0, 6.6). Spores and caps of G. meredithae contained 13 and 11 allergen bands, respectively, on IEF blots. SDS-PAGE of G. meredithae spore and cap showed one and four bands, respectively, by CB staining, but IgE blots showed 13 bands in cap and 17 in spore. Culture mycelia of G. lucidum and G. applanatum attained significant and essentially constant RAST activity by day 4. Activity was also present in culture supernatant by day 4. Blots of mycelium and supernatant detected a single allergen in day-8 mycelia and subsequently six allergen bands in day-16 mycelia and eight in day-16 supernatant (one appeared as a doublet). These data show that Ganoderma extracts contain a complex mixture of allergens. Differences among species were minor; spores and mycelia are apparently better sources of allergens than caps.