SDF-1 increases BFU-E and CFU-G colony formation by PB Inc⁻ CD34⁺ progenitor cells.

PB CD34⁺ cells were purified without incubation on a plastic support (Inc⁻) and plated in duplicate at a density of 500 cells/mL on semisolid Stem α ID medium containing IL-3, IL-6, IL-11, SCF, G-CSF, GM-CSF, Epo, and various concentrations of SDF-1. Colonies were scored on day 14, and results are expressed as a percentage of SDF-1 untreated control (CT) cells (mean ± SD). Control colony numbers were 53.7 ± 7 (BFU-E); 15.5 ± 4.2 (CFU-G); 5.4 ± 1.6 (CFU-M); 0.75 ± 1.3 (CFU-GM); and 1.5 ± 0.4 (CFU-Mix). The control plating efficiency (calculated on the total number of colonies) was 16.1% ± 3.6% (n = 5 independent experiments).* indicates significant difference from control values (P < .05); □, SDF-1 (0.01 ng/mL; , SDF-1 (0.05 ng/mL; ▨, SDF-1 (0.1 ng/mL); ▪, SDF-1 (0.5 ng/mL).