Development and characterisation of a monoclonal antibody to detect the mycotoxin roquefortine C

Authors: Maragos, Chris

Submitted to: Food Additives & Contaminants
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/4/2020
Publication Date: 7/30/2020
Citation: Maragos, C.M. 2020. Development and characterisation of a monoclonal antibody to detect the mycotoxin roquefortine C. Food Additives & Contaminants. 37(10):1777-1790. https://doi.org/10.1080/19440049.2020.1781937.
DOI: https://doi.org/10.1080/19440049.2020.1781937

Interpretive Summary: Two toxic fungal metabolites, Penitrem-A and roquefortine C (ROQC), have been associated with diseases in humans, dogs, and cattle following consumption of moldy food (walnuts, beer) or feedstuffs (corn silages). A scientist at the Agricultural Research Service in Peoria, Illinois, has developed a rapid screening assay for ROQC in nut extracts ('milks') and in the serum of dogs. A small survey of commercial nut milks indicated the presence of extremely low levels that are unlikely to be hazardous. The assay, however, is the first to be developed to detect ROQC in serum, and provides a rapid, sensitive, screening tool that may be useful in the diagnosis of mycotoxin-induced poisoning of dogs.

Technical Abstract: Roquefortine, also known as roquefortine C (ROQC) is a fungal secondary metabolite (mycotoxin) that is produced by some of the same Penicillia as the tremorgen penitrem-A (PEN-A). The two mycotoxins have been linked to sporadic cases of toxicosis in dogs, cattle, and humans, leading some to consider ROQC as a biomarker of PEN-A. Reported here are the development of a monoclonal antibody (mAb) and associated competitive enzyme linked immunosorbent assay (ELISA) for the screening of ROQC in extracts of nuts (nut “milks”), and dog serum. The ELISA was sensitive for ROQC, with a level of 0.117 ng ml-1 inhibiting color development by 50% (IC50), a limit of detection of 0.026 ng ml-1, and a dynamic range (IC20 to IC80) of 0.038 to 0.289 ng ml-1 in buffer. The assay was tolerant to significant levels of methanol. Recoveries from 4 types of nut milks spiked over the range of 0.25 to 2 ng ml-1 were in the range of 83.5% to 116%. A small survey of commercial nut “milks” and “creamers” indicated 4 of 35 samples contained ROQC at levels so low that they are unlikely to be significant to human health (< 0.6 ng ml-1). The assay was also applied to canine serum. Recoveries from serum spiked over the range of 0.2 to 5 ng ml-1 ranged from 98.1 to 123%. The results suggest the ELISA can be applied to the screening of food products, such as nut extracts, as well as for the screening of serum from dogs suspected to be suffering from mycotoxin-induced tremors.