Figure 3.

Inhibition of [¹²⁵I]VEGF₁₆₅ binding to the surface of endothelial cells by RAFL antibodies. Log phase or confluent endothelial cell cultures were incubated with [¹²⁵I]VEGF₁₆₅ (25 pM) in the presence of various RAFL antibodies; nonblocking anti-VEGFR2 IgG, 1A8; blocking rabbit polyclonal anti-VEGFR2, TO14; blocking mouse monoclonal anti-VEGFR1, clone 10.2; or unlabeled VEGF₁₆₅ (2.5 nM). All antibodies were added at a final concentration of 5 µg/ml. After 4 hours of incubation at 4°C, cells were washed and specific VEGF₁₆₅ binding was determined as described under Materials and Methods section. The mean percent of VEGF blocking ±SEM is presented. Insert: Relationship between [¹²⁵I]VEGF₁₆₅ binding and concentration. A VEGF₁₆₅ concentration of 25 pM gives about 90% maximal binding.