Hematopoietic and endothelial cell development from TEK⁺ fraction of AGM cells at 10.5 dpc. Each number of TEK⁺ or TEK⁻ cells (2,000) from AGM at 10.5 dpc was cocultured with OP9 cells. Hematopoietic cells were developed from the TEK⁺ fraction for 10 days of culture (A). These were not observed in the culture of the TEK⁻ fraction (B). After cell suspensions were removed, the OP9 cell layer was immunostained with PECAM-1 MoAb. PECAM-1⁺ endothelial cells formed a network in the culture of the TEK⁺fraction (C). No PECAM-1⁺ cells were detected in the culture of the TEK⁻ fraction (D).