SDF-1 increases CFU-G, CFU-M, CFU-GM, and CFU-Mix colony formation by PB Inc⁺ CD34⁺ progenitor cells in synergy with SCF.

PB CD34⁺ progenitor cells purified after overnight incubation on a plastic support (Inc⁺) were incubated for 48 hours in serum- and cytokine-free liquid culture medium (Stem α A) (A) without or (B) with anti–TGF-β antibody (5 μg/mL). Cells were harvested, counted, and plated in duplicate, at a density of 500 cells/mL, on semisolid Stem α medium containing Epo (control medium) and various combinations or individual cytokines (GM-CSF, IL-3, SCF, IL-3 + SCF, IL-3 + SCF + GM-CSF); SDF-1 (0.05 ng/mL) was added or not to the culture medium. Results of 2 independent experiments are expressed as the number of colonies scored on day 14. * indicates significant difference from control values: P < .05.