Abstract
A hybrid hybridoma (tetradoma) that produces bispecific monoclonal antibodies (mAbs) 2 , which recognize two different epitopes on the A chain of βt-bungarotoxin (β 1 -bgt) at peptide sequences 46-51 and 100-106, has been obtained by fusing two hybridoma cell lines. The bispecific mAb were observed to inhibit 98% of the enzymatic activity of β 1 -bgt and neutralize its lethal toxicity completely. The avidity between the bispecific mAb and β 1 -bgt was noted to be 4.5 x 10 10 (liter/nmol), which is about 45-150 folds higher than the avidity of its two parental mAbs. All the soluble complexes, obtained from bispecific mAb and β 1 -bgt with different molar ratios, emerged in the void volume of size exclusion chromatography column, indicating multiple complexes of β 1 -bgt and bispecific mAb were formed. Based on these results, it indicated that the binding of bispecific mAb with its two epitopes on β 1 -bgt, which facilitates the immune-complex formation and enhances the avidity, also highly neutralizes the biological activity of β 1 -bgt.