Differential expression of CD14 and CD16 allows the characterization of 2 subsets of hESC- and fetal liver–derived CD14⁺ cells. (A) CD14 and CD16 expression on cells issued from day 21 hESCs (top panel), day 10 fetal liver CD34⁺ cells (middle panel), and day 10 adult peripheral blood CD34⁺ cells (bottom panel). hESCs were cultured as described in the legend to Figure 1; fetal liver and adult CD34⁺ cells were cultured in the presence of M-CSF (50 ng/mL), GM-CSF (20 ng/mL), IL-3 (100 U/mL), and FLT3-L (10 ng/mL). Blue indicates CD14^highCD16⁺ cells; purple indicates CD14^lowCD16⁻ cells. Right panel shows the forward (FSC) and size (SSC) scatter properties of CD14⁺ cells. (B) Embryonic, fetal, and adult CD14^lowCD16⁻ cells were sorted and cultured in the presence of IL-3 or GM-CSF or M-CSF for 9 days before assessing cell surface expression of CD14 and CD16.