Figure 2.

Effects of MMAE conjugation on hertuzumab binding to HER2. (A) Flow cytometric assay. Binding of hertuzumab-MMAE and hertuzumab to HER2-positive human gastric cancer cells. NCI-N87 cells were incubated with hertuzumab (Red) and hertuzumab-MMAE (Blue). Anti-CD19 mAb was used as a negative control. Cell membrane bound antibodies or ADCs were detected using FITC labeled anti human IgG by flow cytometry. (B) Immunohistochemistry. Binding specificity of hertuzumab-MMAE for tissue sections. HER2 overexpressing gastric cancer, breast cancer, ovarian cancer and HER2 negative ovarian cancer tissue sections were collected from patients and subjected to immunohistochemical staining with hertuzumab-MMAE. The HER2-positive tumor samples showed an intense staining and no immunoreactions occurred in HER2-negative ones. HER2 status of each section was confirmed by our pathology department.