Fig. 9. TGFß1 and activin A in VEGF-mediated expansion of SCL-expressing cells, hematopoietic and endothelial cell differentiation. Day 6 Scl^+/CD4 EB cells generated in serum-free conditions in the presence of BMP4; BMP4+VEGF; BMP4+VEGF+TGFß1; or BMP4+VEGF+activin A were subjected to three-color analyses for FLK1, CD4 and hematopoietic or endothelial markers. (A) The percentage of FLK1⁺CD4^– (lower right), FLK1⁺CD4⁺ (upper right) or FLK1^–CD4⁺ (upper left) cells is shown. Statistical values are shown on the right. (B) The percentage of TER119 and CD31-positive cells is shown. (C) EB cells generated in the presence of FCS; SR+BMP4; SR+BMP4+VEGF; SR+BMP4+VEGF+TGFß1; or SR+BMP4+VEGF+activin A were subjected to hematopoietic re-plating. No hematopoietic colonies formed when EB cells from SR were re-plated, thus not shown. Hematopoietic colonies were counted 5-7 days after re-plating. Error bars indicate standard deviations from triplicate plating.