Enhancing effects of conditioned medium produced by mature (LPS-stimulated) TGF-M-DCs on expansion of CFU-GM progenitors from CB. (A) CM from TGF-M-DCs selectively expands CFU-GM ex vivo in synergy with SFT. Freshly isolated CD34⁺ cells (1 × 10⁴/mL) were incubated with CM from M-DCs, TGF-M-DCs, GM-DCs, TGF-GM-DCs, control CM, or control medium plus or minus SFT for 1 week. Cells were harvested and plated in triplicate. Fold expansion of CFU-GMs after 1-week culture was determined. Data represent a summary of CM from 8 different CB donors. Average fold expansion of CFU-GMs is shown on the top of each bar. (B) Neutralizing anti–M-CSF Ab, but not control Ab, blocks the ex vivo myeloid-enhancing activity of TGF-M-DC CM. Isolated CD34⁺ cells (1 × 10⁴/mL) were cultured with those factors as indicated on the x-axis in the presence of SFT for 1 week. Fold expansion of CFU-GMs after 1-week culture is shown on the y-axis. The average fold-expansion level of CFU-GMs is shown on the top of each bar. The data represent an average plus or minus SEM from 4 experiments for the neutralizing anti–M-CSF and 2 experiments for the recombinant M-CSF.