Production of monoclonal antibody against albendazole and its metabolites with homogeneous cross-reactivity and its application in lateral flow immunoassay

To avoid false-negative or false-positive results in immunoassays caused by non-uniform antibody cross-reactivity during the detection of the sum of albendazole sulfoxide (ABZSO), albendazole sulfone (ABZSO 2 ), and albendazole-2-aminosulfone (ABZNH 2 SO 2 ) (expressed as albendazole residues), the preparation of a group-specific antibody with homogeneous cross-reactivity is crucial for accuracy. Herein, a novel hapten was designed by introducing a urea structure containing active groups from 5-(propylthio)-1H-benzo[d]imidazole-2-amine. Through monoclonal antibody preparation technology, a broad-spectrum monoclonal antibody 9D9 (mAb 9D9) was prepared with IC 50 values of 0.59, 0.98, 0.41 and 1.13 ng/mL for ABZ, ABZSO, ABZSO 2 , and ABZNH 2 SO 2 , respectively. The ability of mAb 9D9 to uniformly recognize ABZ and its three metabolites was attributed to residues Phe-94 of CDRL3, Glu-103 of CDRH3, and Ser-97 of CDRL3, which formed π-alkyl, π-anion, and hydrogen bonds with the sulfur-containing side chain, benzene ring, and secondary amine on the benzimidazole ring, respectively. Finally, a rapid and accurate lateral flow immunoassay was established for the screening of ABZ and its three major metabolites in animal-derived foods.