Original Paper

Human Serum IgE Reacts with a Metarhizium anisopliae Fungal Catalase
Marsha D.W. Ward^a, Maura J. Donohue^b, Yong Joo Chung^a, Lisa B. Copeland^a, Jody A. Shoemaker^b, Stephen J. Vesper^b, MaryJane K. Selgrade^a

United States Environmental Protection Agency, Office of Research and Development,
^aNational Health and Environmental Effects Research Laboratory, Research Triangle Park, N.C., and
^bNational Exposure Research Laboratory, Microbiological and Chemical Exposure Assessment Research Division, Cincinnati, Ohio, USA

Address of Corresponding Author

Int Arch Allergy Immunol 2009;150:343-351 (DOI: 10.1159/000226235)

  Key Words

• Allergen
• Catalase
• Fungus
• IgE
• Mass spectrometry

  Abstract

Background: Previous studies have demonstrated that Metarhizium anisopliae extract can induce responses characteristic of human allergic asthma in a mouse model. The study objectives were (1) to identify and characterize the M. anisopliae mycelia extract (MYC) proteins that are recognized by mouse serum IgE, (2) to determine if human serum IgE reacts with these proteins, and (3) to determine if these IgE-reactive proteins are found in other fungi. Methods: Asthmatic human serum IgE, M. anisopliae crude antigen (MACA) immunized mouse serum IgE, and anti-catalase antibodies were used to probe one- and two-dimensional gel electrophoresis blots of MYC. Results: Mass spectrometry analysis identified catalase as a mouse IgE-reactive protein. This identification was confirmed by assaying catalase activity in the extract and extract immunoblots probed with anti-catalase antibody. Six adult asthmatic sera contained IgE, but not IgG, that was reactive with mycelia extract proteins. A similar protein profile was seen when blots were probed with either mouse anti-MACA IgE or anti-bovine liver catalase antibodies. Furthermore, these mouse anti-MACA and anti-catalase antibodies were cross-reactive with other mold extracts (skin prick testing mix) and Aspergillus niger catalase. Conclusions: Some human asthmatics have developed IgE that reacts with an M. anisopliae catalase, most likely due to cross-reactivity (minimal IgG development). The cross-reactivity among fungal catalases suggests that IgE-reactive catalase might be useful for exposure assessment. Additionally, the similarity of protein profiles visualized with both human and mouse serum IgE suggests that allergy hazard identification can be facilitated using a mouse model.

Copyright © 2009 S. Karger AG, Basel

  Author Contacts

Correspondence to: Dr. Marsha D.W. Ward
National Health and Environmental Effects Research Laboratory
United States Environmental Protection Agency, Office of Research and Development
109 T.W. Alexander Drive, MD B143-01, Research Triangle Park, NC 27711 (USA)
Tel. +1 919 541 1193, Fax +1 919 541 0026, E-Mail ward.marsha@epa.gov

  Article Information

The US Environmental Protection Agency through its Office of Research and Development funded and managed the research described in this paper. It has been reviewed in accordance with the Agency’s peer and administrative review policies and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.

Received: November 6, 2008
Accepted after revision: March 12, 2009
Published online: July 1, 2009
Number of Print Pages : 9
Number of Figures : 5, Number of Tables : 1, Number of References : 35