FIG. 6.

Specific inhibition of sCAR-EGF-mediated Ad binding. ³H-Ad was preincubated for 30 min at room temperature with 0.4 μg of sCAR-EGF. Human epidermoid carcinoma A-431 cells, overexpressing EGFR, were preincubated for 30 min at 4°C in the presence or absence of either human EGF or anti-EGFR MAb at different concentrations (0.52 to 13.2 μg/ml). ³H-Ad/sCAR-EGF samples (10⁵ cpm) were then added and allowed to bind for 1 h at 4°C. Cells were washed by centrifugation, and radioactivities of cell pellets were determined in a beta counter. Data are presented as the percentage of input ³H-Ad bound after washing and calculated as the cumulative mean ± SD of triplicate determinations.