Effect of an FGFR1 antibody on EC proliferation. ECs were plated on gelatin-coated wells in McCoy 5A medium supplemented with 20% FBS, 50 μg/mL ECGS, and 100 μg/mL heparin and allowed to adhere for 6 hours. The cells were then washed twice with McCoy medium and incubated in serum-free medium containing 1% Nutridoma and 5 μg/mL of either FGFR1 or control mouse IgG. After 60 minutes, 25 ng/mL FGF-2,with or without 10 μg/mL fibrinogen, and 1 μCi/mL (0.037 MBq) ³H-thymidine were added to the medium. After 24 hours, nonadherent cells were removed, and isotope incorporated into DNA was precipitated with TCA, collected by vacuum filtration, and measured by scintillation counting. The results are the mean ± SD of 3 separate experiments.