Figure 4.
(A) Colony-forming cells (CFC) of the PA are enriched in the VEGFR2+ population as compared with unsorted or VEGFR2− cells. HC, hemopoietic colonies; EC, endothelial colonies. Each column represents the mean number of CFC calculated per 1 × 103 cells obtained in three independent sorting experiments ± SD. (B) Limiting dilution analysis of VEGFR2+ cells. One of two experiments showing similar results. The frequency of colony-initiating progenitors at 37% negative wells was, according to the Poisson analysis, 1/22 for HC and 1/10 for EC in the presence of VEGF and 1/11 for HC obtained without VEGF. (C) Dose-dependent stimulation of endothelial cell development by VEGF. Values represent the mean ± SD from two experiments.