Isolation of CD45⁺ cells reveals their hematopoietic progenitor potential. Following 15 days of differentiation in cytokines +/- BMP-4, EBs were dissociated and stained with a CD45 monoclonal antibody. Viable CD45⁺ and CD45^- cells were isolated by fluorescence activated cell sorting, by first gating on 7-AAD–excluding cells (top left panel) and then on CD45⁺ and CD45^- populations (right panel). The sorting gates were set based on isotype controls (bottom left panel).