Monoclonal-antibody-based immunoassays for the mycotoxins NX-2 and NX-3 in wheat

Authors: Maragos, Chris; Vaughan, Martha; McCormick, Susan

Submitted to: Toxins
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/15/2024
Publication Date: 5/18/2024
Citation: Maragos, C.M., Vaughan, M.M., McCormick, S.P. 2024. Monoclonal-antibody-based immunoassays for the mycotoxins NX-2 and NX-3 in wheat. Toxins. https://doi.org/10.3390/toxins16050231.
DOI: https://doi.org/10.3390/toxins16050231

Interpretive Summary: New fungal toxins (mycotoxins) continue to be discovered. One such group of toxins are the NX-toxins, which are produced by certain strains of a group of fungi that cause Fusarium Head Blight, an economically important disease of cereal crops. The toxins are similar to the better known "vomitoxin" and the strains that produce them have been isolated in the northeastern United States and in Canada. There are currently no rapid screening tests for this group of toxins. Researchers with the USDA-ARS in Peoria, Illinois, developed several antibody-based screening assays for the NX toxins in wheat. These are the first rapid screening tests for this group of toxins and will be important tools for the diversion of infested commodities from the human food and animal feed supply chains.

Technical Abstract: Fungal infestation of crops can cause major economic losses. Toxins produced by the causative fungi (mycotoxins) represent a potential safety hazard to people and livestock consuming them. One such mycotoxin is deoxynivalenol (DON, aka vomitoxin) a trichothecene associated with Fusarium Head Blight of wheat. DON is commonly found in cereal crops worldwide. A group of trichothecene mycotoxins closely related to DON, the NX toxins, have been reported to occur in the Northeastern United States and southern Canada. While many commercial immunoassays are available to detect DON there are no rapid screening assays for the NX toxins. We describe the development and isolation of three monoclonal antibodies (mAbs) specific towards two NX toxins: NX-2 and NX-3. The mAbs did not recognize DON or several other closely related trichothecenes. One of the mAbs was selected for development of an enzyme-linked immunosorbent assay (ELISA) for NX-2 and NX-3 in wheat. The dynamic ranges for the assay were 7.7 to 127 ug/kg for NX-2 and 59 ug/kg to 1540 ug/kg for NX-3 in wheat. Recoveries from spiked wheat averaged 84.4% for NX-2 and 99.3% for NX-3, with RSDs of 10.4% and 11.3% respectively (n=24). The results suggest that this assay can be used to screen for NX toxins in wheat at levels relevant to human food and animal feed safety.