C/EBPα inhibits PU.1-induced dendritic cell development from human CD34⁺ pluripotent myeloid progenitor cells.

Human CD34⁺ cord blood cells were retrovirally transduced with either PU.1 or C/EBPα or were cotransduced with PU.1 and C/EBPα. Cells transduced with retrovirus containing empty vector were prepared as negative control cells (Mock) and were processed in parallel. Cells were cultured in the presence of mixed cytokines that facilitate myeloid differentiation (SCF, IL-3, GM-CSF, and G-CSF). After 10 days, cell morphology was evaluated by Giemsa staining (A-D; original magnification × 100); percentages of dendritic cells, macrophages, and granulocytes were evaluated by manual cell count; monocyte and granulocyte cell surface antigen (CD14, CD15) expression and expression of dendritic cell surface antigens (CD1a, HLA-DR, CD80, CD86) were analyzed by flow cytometry (E, F).