Preparation and characterization of beta(1)-bungarotoxin bispecific monoclonal antibody

A hybrid hybridoma (tetradoma) that produces bispecific monoclonal antibodi es (mAbs)(2), which recognize two different epitopes on the A chain of beta (1)-bungarotoxin (beta(1)-bgt) at peptide sequences 46-51 and 100-106, has been obtained by fusing two hybridoma cell lines. The bispecific mAb were o bserved to inhibit 98% of the enzymatic activity of beta(1)-bgt and neutral ize its lethal toxicity completely. The avidity between the bispecific mAb and beta(1)-bgt was noted to be 4.5 x 10(10) (liter/nmol), which is about 4 5-150 folds higher than the avidity of its two parental mAbs. the soluble c omplexes, obtained from bispecific mAb and beta(1)-bgt with different molar ratios, emerged in the void volume of size exclusion chromatography column , indicating multiple complexes of beta(1)-bgt and bispecific mAb were form ed. Based on these results, it indicated that the binding of bispecific mAb with its two epitopes on beta(1)-bgt, which facilitates the immune-complex formation and enhances the avidity, also highly neutralizes the biological activity of beta(1)-bgt.