Preparation and characterization of anti-sulphamethoxazole (SMX) monoclonal antibody

Anti-sulphamethoxazole (SMX) monoclonal antibody (MAb) has a significant role in monitoring of SMX residue levels in edible animal products. In this study, SMX was diazotizated and coupled to human serum albumin to form an antigen for animal immunization. Anti-SMX hybridomas were prepared by cell fusion using an enzyme-linked immunosorbent assay (ELISA) method to screen for positive hybridomas. A monoclonal antibody (MAb) against SMX was secreted by the hybridomas and its specificity was characterized by ELISA, SDS-PAGE and Western-blot. The results showed that the SMX-MAb was of the IgG1 type and its molecular weight was 162 000 Daltons. The affinity constant of MAb for the conjugated antigen was 2.3×10⁸ l/mol. The detection limit of 50% inhibition rate in the range 10 pg/mL to 10 ng/mL was 0.82 ng/mL and the recoveries of SMX were above 90%. There was no cross-reaction between MAb and SMX analogues.