Figure 2

Binding affinities of anti-HER2 antibodies. (A) HER2 ECD ELISA assay showing the binding strengths of five monoclonal antibodies. HER2 ECD-coated plates were incubated with increasing concentrations of anti-HER2 antibodies, followed by alkaline phosphatase-conjugated anti-mouse IgG antibodies. Y axis shows the absorbance (OD) reading at 405 nm following incubation with alkaline phosphatase substrate. T-bars: SD. (B) and (C), Flow cytometric analysis of antibody binding to low HER2-expressing T47D (B) and high HER2-expressing BT-474 (C) breast cancer cells. Fixed single-cell suspensions were incubated with anti-HER2 antibodies, followed by Alexa-488-conjugated secondary antibodies and fluorescence intensities were measured using flow cytometry.