Allergenicity and immunogenicity of Basidiomycetes.

Species selected from six families of the class Basidiomycetes were evaluated for allergenicity in atopic and nonatopic individuals and for immunogenicity and antigenic cross-reactivity in experimental animals. Between 42% and 68% of atopic asthmatics demonstrated positive Type 1 wheal-and-flare skin reactivity to basidiomycete metabolic and somatic antigens. Sixty-four percent of skin test-positive atopic asthmatics exhibited positive RAST to as basidiomycete metabolic antigen and 50% were positive to somatic antigen. Negative RAST results were obtained in all nonatopic control sera. Only an occasional individual demonstrated positive serum antibasidiomycete precipitins by counterimmunoelectrophoresis. All basidiomycete species studied were highly immunogenic in the rabbit and most appeared to contain an electrophoretically heterogenous group of antigens with predominant anodal mobility. Ouchterlony double-diffusion analysis employing hyperimmune rabbit antisera indicated the presence of shared antigens among all basidiomycete species with the exception of Pleurotus. Rabbit antibasidiomycete sera did not cross-react with antigens of several common species of the Fungi imperfecti. Results indicate that many atopic asthmatics of the Gulf South area demonstrate IgE-medicated hypersensitivity to basidiomycete antigens as evidenced by positive wheal-and-flare skin reactivity and/or RAST. Basidiomycetes are also immunogenic in the rabbit and possess antigens that do not cross-react with those of certain Fungi imperfecti.