Production and characterization of a single chain variable fragment (scFv) against the mycotoxin deoxynivalenol

Deoxynivalenol (DON) is a mycotoxin produced by certain fungi that infest cereal grains. A hybridoma cell line producing a monoclonal antibody (Mab) was used as the starting point in the development of a recombinant single chain variable fragment antibody (scFv) recognising DON. The scFv and Mab were characterised using two immunoassay formats: competitive direct enzyme-linked immunosorbent assay (CD-ELISA) and biolayer interferometry (BLI). Using CD-ELISA the IC(50)s for DON were 36.1 and 13.8 ng/ml for assays based on the scFv and Mab, respectively. The cross-reactivity to DON analogs was very similar for the scFv and the Mab. The real-time binding of the antibodies to an immobilised DON-protein conjugate was also monitored. In competitive BLI assays the IC(50)s using the scFv and Mab were 68.3 and 15.8 ng/ml, respectively. The results suggest that sensitivity of assays, but not selectivity, was affected by removal of the constant regions of the Mab.