Development of a New Monoclonal Antibody by More Active Enramycin A and Indirect Competitive ELISA for the Detection of Enramycin in Edible Animal Tissues

In this research, we developed a new sensitive and specific monoclonal antibody (mAb)-based indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) to detect enramycin residues in edible animal tissues. Enramycin has two main components, Er-A and Er-B. Due to their similar structure, we creatively used the more active Er-A component to synthesize immunogen at different positions to prepare antibodies. A highly sensitive and specific mAb (2H1F91) was obtained, and an ic-ELISA of heterologous coating antigen was also constructed. Not surprisingly, the 2H1F91 exhibited cross-reactivity to Er-B (91.9%), enramycin (97.8%), and less than 0.01% with other four polypeptide antibiotics, which showed the antibody had superior specificity. After the optimization of the conditions, the developed ic-ELISA showed high sensitivity (IC50 was 108.5 ng/mL). The spiked experiments indicated that the limits of detection were 144.8 μg/kg and 98 μg/kg in the pork and chicken matrix and mean recoveries ranged from 72.32 to 125.97% with the coefficient of variation less than 12%. The results of ic-ELISA showed a good linear relationship (R2 = 0.9644) with HPLC results, confirming the ic-ELISA which we developed was suitable for the rapid detection of enramycin in animal samples.