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CATALASE FROM A FUNGAL MICROBIAL PESTICIDE INDUCES A UNIQUE IGE RESPONSE.
Citation:
WARD, M. D., L. B. COPELAND, M. J. DONOHUE, Y. CHUNG, J. A. SHOEMAKER, AND S. J. VESPER. CATALASE FROM A FUNGAL MICROBIAL PESTICIDE INDUCES A UNIQUE IGE RESPONSE. Presented at 45th Annual Society of Toxicology Meeting 2006, San Diego, CA, March 05, 2005 - March 09, 2006.
Description:
BALB/c mice exposed by involuntary aspiration to Metarhizium anisopliae extract (MACA), a microbial pesticide, have shown responses characteristic of human allergic lung disease/asthma. IgE-binding proteins have been identified in MACA by Western blot analysis, 2-dimensional (2-D) gel electrophoresis, mass spectrometric analysis, and database searches: the peptide sequences from several protein spots were homologous to the enzyme catalase. Catalases are reactive oxygen species-neutralizing enzymes that are ubiquitous in nature. The objective of this study was to investigate whether MACA associated catalase is antigenically similar to catalases from different sources. Western blots of commercial preparations of bovine liver catalase, Aspergillus catalase, Mold Mix 1 and Mold Mix 2 (Greer Laboratories), which are used in human skin prick testing, and MACA were probed with Aspergillus catalase specific antiserum and anti-IgG. Aspergillus as well as bovine liver catalase, MACA, and Mold Mix 1 reacted with this antiserum. Mold Mix 2 did not. Thus, with respect to IgG MACA catalase appears to cross react with Aspergillus, bovine, and mold mix 1 catalase. However, when these same preparations were probed with MACA hyperimmune serum and anti-IgE, only binding to MACA was demonstrated. This data suggests that many catalases have some sequence as well as functional homology and that the IgG inducing epitopes may fall into these homologous regions. However, the ability to induce an IgE response may involve sequences/epitopes unique to a given source of the enzyme. (This abstract does not reflect EPA policy).