Figure 3

Inhibition of HER-2/neu ECD-Fc fusion protein binding on trastuzumab F(ab′)2 fragments by purified scFv 69 by competitive ELISA. Increasing amounts of inhibitor were mixed with HER-2/neu ECD-Fc fusion protein at 2.5 or 5 μg ml−1 and incubated with trastuzumab F(ab′)2 fragments for 1.5 h. HER-2/neu ECD-Fc fusion protein binding was then detected with peroxidase-conjugated anti-HER-2/neu FRP5 mAb (1 : 3000). The results obtained are expressed as percent inhibition at each concentration of inhibitor.