ASPERGILLUS-FUMIGATUS ALLERGEN-I, A MAJOR IGE-BINDING PROTEIN, IS A MEMBER OF THE MITOGILLIN FAMILY OF CYTOTOXINS

A major 18-kD IgE-binding protein from Aspergillusfumigates (AspfI) has been purified. Partial amino acid sequencing of Asp f I showed extensive sequence homology (95%) between Asp fI and a cytotoxin (mitogillin) produced byA. restrictus. Crossinhibition radioimmunoassay using murine monoclonal antibody and human IgG and IgE antibodies showed that AspfI and mito were antigenically indistinguishable. Furthermore, both proteins inhibited protein synthesis in vitro by >90%. Asp fI was expressed in A. fumigates but not in seven other Aspergillus species. The results suggest that AspfI could play a dual role in the pathogenesis of A. fumigates-related diseases by promoting colonization through cytotoxic activity and by causing inflammatory reactions involving IgE antibodies. © 1990, Rockefeller University Press., All rights reserved.