Differentiation of hematopoietic cells derived from endothelial progenitor cells.

(A,B) E10.5 AGM– or yolk sac–derived cells were fractionated into Flk-1⁺CD31⁺ cells and further subdivided on the basis of the expression of ALCAM. A total of 1000 Flk-1⁺CD31⁺ALCAM⁺ or Flk-1⁺CD31⁺ALCAM⁻ cells were cultured with OP9 cell for 7 days in the presence of SCF, Epo, IL-6, and IL-7. After nonadherent cells were harvested, the number of cells was scored (Ai) and the frequency of c-Kit expression was analyzed by FACS (Aii,B). *P < .05. (C) Morphology in each nonadherent cell was examined by May-Grünwald-Giemsa staining; expanded hematopoietic cells in AGM-derived Flk-1⁺CD31⁺ ALCAM⁻ cells (Ci), AGM-derived Flk-1⁺CD31⁺ALCAM⁺ cells (Cii), yolk sac–derived Flk-1⁺CD31⁺ALCAM⁻ cells (Ciii), and yolk sac–derived Flk-1⁺CD31⁺ALCAM⁺ cells (Civ). Note that immature hematopoietic precursor cells were observed in AGM-derived Flk-1⁺CD31⁺ALCAM⁺cells (Cii).