Hapten synthesis and production of monoclonal antibodies to the N-methylcarbamate pesticide methiocarb

With the aim of developing an immunoassay for the detection of the insecticide methiocarb, three compounds with carboxylic spacer arms of different lengths introduced at the carbamate group were synthesized, conjugated to proteins, and used as immunizing haptens in mice. Monoclonal antibodies (MAbs) were subsequently obtained and characterized for their affinity to methiocarb. In the homologous conjugate-coated assay format, MAbs exhibited I-50 values in the 1-10 nM range. Thereafter, a collection of methiocarb haptens with modifications in the aromatic ring structure or in the spacer arm were synthesized to be used as heterologous haptens. These haptens and MAbs were incorporated into several ELISA configurations. Some of the new combinations of immunoreagents and assay format provided a significant improvement in assay sensitivity, reaching I-50 values around 0.1 nM. MAbs seem to be very specific for methiocarb, as evidenced by the negligible cross-reactivity shown by methiocarb metabolites. These immunoreagents are very promising analytical tools for the rapid and sensitive determination of methiocarb in food and in the environment.