Involvement of the outer wall layer of Cladosporium cladosporioides in an IgG-mediated hypersensitivity.

Abstract

The serum of an individual hypersensitive to the fungus Cladosporium cladosporioides reacted with the outer wall layer of germinating spores, immature hyphae, and, to a lesser extent, mature mycelium, as detected by the indirect immunofluorescence assay when goat anti-human IgG, but not goat anti-human IgE, was employed. The outer wall layer of ungerminated spores, however, did not react with the patient's serum and the anti-human IgG probe. When ungerminated spores were vortexed in physiological saline for 1 min, approximately 8 pg of protein/spore was released; this rapid release of protein may have been the cause of the loss of antigenic activity from the outer wall layer of ungerminated spores during the immunoassay process. Immunoblotting revealed the presence of a high molecular weight antigen in all the extracts of the fungus at various stages of the life cycle, including ungerminated and germinating spores, hyphae in the logarithmic phase, mature mycelium, and a culture filtrate of C. cladosporioides.