Anti-idiotypic VHH mediated environmentally friendly immunoassay for citrinin without mycotoxin
Liang Xiong, Xueqin Zhang, Yang Xu, Yanping Li, Deguang Liu, Zhui Tu, Qinghua He
Abstract
Competitive enzyme-linked immunosorbent assay (ELISA) is the most widely used method for rapidly screening of mycotoxins in contaminated food products; however, it involves the use of toxin-protein conjugates as a competitive antigen and toxin standards as calibrators. In this work, a single domain heavy chain antibody (VHH)-based environmentally friendly ELISA (VHH-ELISA) was developed to measure citrinin concentration in Monascus-fermented rice. With this novel indirect competitive VHH-ELISA, the use of a synthetic antigen and pure toxins for operation and environmental safety simultaneously avoided. The assay exhibited a limit of detection of 2.25 ng/mL, with a linear range of 5.0−500.0 ng/mL. VHH-ELISA was then utilized for sample testing, and excellent agreement was observed between VHH-ELISA and high-performance liquid chromatography as a reference. This study provided a novel platform to develop environmentally friendly immunoassays for other toxic small molecules in the application of anti-idiotypic VHHs.