Monoclonal antibodies for the mycotoxins deoxynivalenol and 3-acetyl-deoxynivalenol

The mycotoxin deoxynivalenol (DON) is produced by the mold Fusarium gramine arum and is found worldwide on cereal grains, in particular wheat and maize . Each year this compound, also known as `vomitoxin' causes substantial los ses to agricultural productivity. Three monoclonal antibodies were develope d following the immunization of mice with a conjugate of DON and ovalbumin. One of these antibodies, produced by clone #22, was selected for the devel opment of a competitive direct ELISA (CD-ELISA). This format consists of co mpetition between a DON horseradish peroxidase conjugate (DON-HRP) and free DON for antibody attached to microwell plates. Color development in the as say was inhibited 50% (IC50) by 18 ng DON/ml in phosphate-buffered saline ( PBS). The antibody from this clone showed strong cross-reactivity to 3-acet yl deoxynivalenol (3-Ac-DON), with an IC50 of 2.9 ng ml(-1) Cross-reactivit y to 19 other trichothecene mycotoxins was low. The CD-ELISA was applied to wheat spiked with DON over the range 0.01-10 mu g/g and extracted with a 1 0-fold excess of PBS. The midpoint for color development in the assay using this extraction was 0.27 mu g DON/g wheat. Recoveries over the range 0.05- 5 mu g/g averaged 88.7% with a coefficient of variation of 10.9%. This assa y is sufficiently sensitive and rapid to permit the screening of DON in whe at below the US Food and Drug Administration advisory level of 1 ppm in hum an food.