PDGF-BB induces the down-regulation of Tal-1, CD41, and CD45, markers for primitive and definitive hematopoiesis. (A) Embryoid bodies cultured for 8 days in the absence (basal) or presence of 30 ng/mL PDGF-BB or of VEGF-A165 were stained by immunofluorescence to visualize the expression of CD41 and VE-cadherin. Bars represent 300 μm. (B) Real-time PCR analysis of Tal-1, CD41, and CD45 expression in embryoid bodies cultured in the absence (basal) or presence of 30 ng/mL PDGF-BB or 30 ng/mL VEGF-A for 8 days. Results are expressed as mean ± SD fold induction of 3 separate experiments. *P < .05; **P < .005; ***P < .001.