Hematopoietic and endothelial cell development from single TEK⁺ cells. Single TEK⁺ cells from AGM at 10.5 dpc were seeded on OP9 in the presence of angiopoietin-1 and IL-3. (A) Hematopoietic cells developed on day 7 of culture in 96-well microtiter plates. (B) Hematopoietic blast cells (b) and OP9 cells (o) were revealed by cytospin preparation with Giemsa staining. These cells were adhered to the stromal layer. (C) PECAM-1⁺ endothelial cells were detected in the presence of angiopoietin-1 (100 ng/mL) and IL-3 (100 U/mL). (D) No PECAM-1⁺ cells were detected in the presence of IL-3 (100 U/mL) alone.