Ochratoxin A mimotope from second-generation peptide library and its application in immunoassay

With the advantage of replacing mycotoxins and their conjugates, mimotopes have been applied to immunoassays, the most common of which were seleted from random phage displayed peptide libraries. However, these mimotopes were limited by the diversities of the peptide libraries. The aim of this study was to demonstrate that a variety of mimotopes can be obtained by constructing a second-generation peptide library. Using mycotoxin ochratoxin A as a model system, a dodecapeptide mimotope was isolated after panning the second-generation peptide library. The half inhibition concentration of the chemiluminescent enzyme-linked immunosorbent assay setup with this mimotope was 0.04 ng/mL, and the linear range was 0.006-0.245 ng/mL. The mimotope was also used to develop a qualitative dipstick assay with a cutoff level of 1 ng/mL. The method not only presents a high sensitivity but also contributes to the development of mimotope-based assays for mycotoxins avoiding the need of synthesizing toxic mycotoxin conjugates.