Fig. 2.

In vitro differentiation of hESC toward hematopoietic lineage. (a) Changes in hematopoietic marker expression after in vitro culture of EGFP⁺ H1 cells on OP9 cells. Cells were analyzed by flow cytometry and gated on EGFP⁺ cells (which typically ranged between 70% and 90% of total live cells). Expression of each marker was determined at the indicated times. (b) Flow cytometric analysis of hematopoietic marker expression in the CD34⁺ cell population (typically <5% of total live cells). (c) hESC-derived hematopoietic progenitor cells give rise to erythroid (Upper) and myeloid (Lower) colonies that express EGFP, as viewed by phase-contrast (Left) and fluorescent (Right) microscopy after 10 days of differentiation on OP9 cells and 14 days of growth in methylcellulose containing erythropoietin, stem cell factor, granulocyte–macrophage colony-stimulating factor, and IL-3.