Induction of hematopoietic molecules and CFCs during hES cells/OP9 coculture. (A) Percentages of CD34⁺, CD31⁺, CD43⁺, CD41a⁺, and CD45⁺ cells (left Y-scale) as determined by flow cytometry, and total numbers of CFCs (right Y-scale) in hES cell/OP9 coculture at days 1 through 10. Day 0 indicates undifferentiated hES cells. (B) Kinetic of different CFC types in hES cell/OP9 coculture. Panels A and B represent mean results from 6 experiments (H1 = 3; H9 = 3); arrows on the top of each figure point to the earliest day when expression of indicated markers or CFCs was detectable. (C) Morphology (left column) and Wright staining of cytospins (right column) of different CFC types. Images captured with an inverted Leica DM1RB microscope (Leica Microsystems) using 5 × objective with numerical aperture 0.12 (left column) and Olympus BX51 microscope (Olympus America Inc., Melville, NY) using 40 × with numerical aperture 0.75 (GM-CFC, M-CFC) and 100 × with numerical aperture 1.30 (E-CFC, GEMM-CFC) objectives (right column) and acquired through Spot RT camera and Spot software (Diagnostic Instruments).