Fig. 2.

Single hinge cleavage caused a loss of antibody dependent cellular cytotoxicity (ADCC) activity in intact pertuzumab (IgG-P) that contributed to less tumor inhibition in IgG with a single proteolytic cleavage in the lower hinge region (scIgG-P) treatment group. a ADCC-targeted lysis of SKOV-3 ovarian cancer cells by IgG-P and scIgG-P was examined using the electrode impedance assay. SKOV-3 cells (5000 cells/well) were seeded on the E-plate as the target cell and peripheral blood mononuclear cells (25,000 cells/well) isolated from a single donor were used as the immune effector cells in complete cell culture medium containing scIgG-P (30 nM) and IgG-P (30 nM). The cell index after 96 h of incubation was the experimental end point (n = 3). The percentage of cell lysis was defined as: (cell index of control group – cell index of treatment group)/cell index of control group) × 100. b Tumor volumes from nude mice (n = 5) were inoculated subcutaneously with 5 × 10⁶ BT474 human breast cancer cells and treated with isotype IgG1 control, IgG-P, scIgG-P, or IgG-P N297A at 10 mg/kg weekly for a total of five doses until tumors reached an average size of 100mm³. c Tumor volumes at the end time point of the nude mice xenograft study for individual mice treated with isotype IgG1 control, IgG-P, scIgG-P, and IgG-P N297A. Tumor size was measured twice a week. The error bars in the graphs depict the standard deviation (SD) obtained in three independent experiments. *p < 0.05,**p < 0.01