FIGURE 6.

EMP2 antibodies reduced cellular viability and tumor load. A, 2 × 10⁵ GM5, U87MG, U87/EGFR VIII, T98, and U373 cells were incubated for 72 h with a vehicle control (PBS) or molar equivalents of the anti-EMP2 diabody or anti-EMP2 IgG1. Cellular viability was enumerated using trypan blue exclusion. Data represent viability as a percentage of control from three independent experiments. B, GM5 and T98 cells were treated as above, with cellular viability determined using annexin V and propidium iodide staining. The experiment was repeated three times, and a representative graph is shown. C, U87/EGFR VIII cells were inoculated subcutaneously in BALB/c nude mice. When tumors reached 4 mm³, they were treated twice weekly (1st week, 1.0 mg/kg; 2nd week, 2.5 mg/kg), with anti-EMP2 diabody or control diabody. Left, tumor size (arrow indicates start of treatment). Right, tumor histology after treatment. Magnification, ×100. n = 6. *, p < 0.05 as determined by Student's t test. D, U373 cells were subcutaneously injected into athymic nude mice. When tumors reached 4 mm³, mice were treated systemically (intraperitoneally) with anti-EMP2 IgG1 or control IgG (3 mg/kg). Left, tumor growth. Right, tumor histology at day 65. Magnification, ×100. n = 6. *, p < 0.05 as determined by Student's t test.