RelB promotes human monopoiesis but not granulopoiesis. CD34⁺ cells or U937 cells were transduced with retroviral vectors encoding p100ΔN, empty control, or RelB 5′ of IRES-GFP. Diagrams show representative gated GFP⁺ cells (A) CD34⁺ cells stimulated in the presence of M-CSF plus IL-6, FL. and SCF for 10 days analyzed for CD11b versus CD14 expression. (B) CD34⁺ cells stimulated in the presence of G-CSF, SCF, and FLT3L for 6 days and analyzed for CD14 versus CD15 expression. (C) U937 cells analyzed for CD14 versus CD11b expression (top panel). Right diagram show a positive control (cells 72 hours after vitamin D3 stimulation). (D) CD34⁺ cells stimulated in the presence of expansion mix (SCF, FLT3L, TPO) for 7 days analyzed for CD14 versus CD11b expression. Markers were set according to negative control stainings. (A-D) Data are representative of at least 3 experiments. Numbers on the plots represent percentages of gated cells within the indicated quadrants.