Immunochemical and molecular characteristics of monoclonal antibodies against organophosphorus pesticides and effect of hapten structures on immunoassay selectivity

To produce broad-selective monoclonal antibody (Mab) for organophosphorus (OP) pesticides, heterologous enzyme-linked immunosorbent assays (ELISAs) were used for hybridoma screening. Six Mabs with different cross-reactivity to OP pesticides were produced. Based on the broad-selective Mab 5F7, homologous and heterologous indirect competitive ELISAs were developed and the influence of hapten structure on assay selectivity was investigated. Moreover, the receptor-ligand interactions between 5F7 and OP pesticides were simulated to evaluate the broad-selectivity of the Mab. Results showed that, selectivity of the Mab was determined by its molecular properties, and the assay selectivity could be modified when the assay sensitivity was improved sufficiently by heterology. With the most suitable competitor, a broad-selective heterologous ELISA was developed. The IC50 values were estimated to be 7.06 ng/mL for parathion, 32.34 ng/mL for methyl parathion, 164.84 ng/mL for fenitrothion, 96.97 ng/mL for phoxim and 500.94 ng/mL for fenthion.