Figure 3From: A single proteolytic cleavage within the lower hinge of trastuzumab reduces immune effector function and in vivo efficacyBiological characterization of single hinge cleaved trastuzumab compared with the intact trastuzumab antibody in vitro. (A) Histograms of trastuzumab and single hinge cleaved trastuzumab (scIgG-T) binding to HER2 expressed on BT474 cells using a flow cytometer. (B) Concentration-dependent binding of trastuzumab and scIgG-T to HER2 expressed on BT474 breast cancer cells as measured by flow cytometer. Mean fluorescence intensity (MFI) is plotted against each antibody concentration (nM) on the x axis. (C) Effect of trastuzumab and scIgG-T on total HER2 expression, pHER2 (Y1289), pAKT (S473), and pErk1/2 in BT474 cells as determined by western blotting. (D) Inhibition of BT474 breast cancer cell proliferation by trastuzumab and scIgG-T (n = 4). Percentage of cell growth inhibition calculated as: (fluorescence signal of control group - signal of treatment group)/signal of control group×100.Back to article page