Establishment of Indirect Competitive ELISA Method for Detecting Amanitin in Mushroom

Objective: This study aims to establish an indirect competitive enzyme-linked immunosorbent assay for the detection of amanitin (AMA) in mushroom. Methods: In this study, the hapten was obtained by introducing 6-aminocaproic acid into the carboxyl position of the α-amanotropin molecule through EDC/NHS, and further coupled with different carrier proteins to prepare immunogens and coating antigen. Afterwards, Balb/c mice were immunized with the immunogen to prepare monoclonal antibodies. Based on the obtained antibody, an indirect competitive ELISA method for the detection of amanitin in mushroom was established by optimizing the working concentrations of coating antigen and antibody, coating conditions, blocking conditions, working concentrations of enzyme labeled secondary antibody and incubation time. Finally, the sensitivity, recovery rate, intra batch and inter batch variation of the established method were evaluated. Results: The molecular weight of the synthesized hapten in this study was 1033.12, and the coupling ratio of the immunogen identified by MALDI-TOF was about 10.03. Based on hybridoma technology, the IC₅₀ of the mouse monoclonal antibody 13H4 was 1.91 μg/L. Based on the obtained monoclonal antibody, the detection limit of the established ic-ELISA method for amanitin in mushroom was 0.88 μg/kg, the recovery rate was 85.66%~113.05%, the intra-assay coefficient of variation was 5.35%~9.54%, and the inter-assay coefficient of variation was less than 15%. Conclusion: The ic-ELISA method established in this study had high accuracy, precision, sensitivity, and stable performance. It provided a simple, reliable and rapid detection method for the analysis of the toxicogen of sudden mushroom poisoning.