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

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 colour 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.

Graphical abstract

KEYWORDS:

• Roquefortine
• penitrem
• antibody
• immunoassay
• nut milk
• serum
• dog

Conflicts of interest

The authors declare no conflict of interest.

Disclaimer

The mention of trade names or commercial products in this publication is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the U.S. Department of Agriculture. The USDA is an equal opportunity provider and employer.

Supplementary material

Supplemental data for this article can be accessed on the publisher’s website.

Additional information

Funding

This work was supported by USDA-Agricultural Research Service project number 5010-42000-0049-00D.