Submitted to: Journal of Food and Agriculture Immunology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 5, 2000
Publication Date: N/A
Interpretive Summary: The fungus F. graminearum causes a disease known as head scab in wheat, which has resulted in substantial losses to U.S. agriculture, particularly in the upper Midwest. Deoxynivalenol (DON), a metabolite produced by Fusarium graminearum, is a mycotoxin capable of causing disease in several animal species. DON has been found in a variety of grains in particular wheat, barley, and maize. This article describes the development of sensitive and rapid methods for the measurement of DON in wheat. The methods are immunoassays based upon highly sensitive and specific monoclonal antibodies for DON and the related trichothecene 3-acetyl-DON.
Technical Abstract: The mycotoxin deoxynivalenol (DON) is produced by the mold Fusarium graminearum and is found worldwide on cereal grains, in particular wheat and maize. Each year this compound, also known as "vomitoxin", causes substantial losses to agricultural productivity. Three monoclonal antibodies were developed following the immunization of mice with a conjugate of DON and ovalbumin. One of these antibodies, produced by clone #22, was seleccted for the development of a competitive direct enzyme linked immunosorbent assay (CD-ELISA). This format consists of competition between a DON horseradish peroxidase conjugate (DON-HRP) and free DON for antibody attached to microwell plates. Color development in the assay with inhibited 50% (IC50) by 18 ng DON/ml in phosphate buffered saline (PBS). The antibody from this clone showed strong cross-reactivity to 3-acetyl deoxynivalenol (3-Ac-DON), with an IC50 of 2.9 ng/ml. Cross reactivitiy to 19 other trichothecene mycotoxins was low. The CD-ELISA was applied to wheat spiked with DON over the range of 0.01 to 10 microgram/g and extracted with a ten-fold excess of PBS. The midpoint for color development in the assay using this extraction was 0.27 microgram DON/g wheat. Recoveries over the range of 0.05 to 5 microgram/g averaged 88.7% with a coefficient of variation of 10.9%. This assay is sufficiently sensitive and rapid to permit the screening of DON in wheat below the U.S. Food and Drug Administration advisory level of 1 ppm in human food.