In vitro effect of 4F on CD34⁺ cell cycle distribution.

Unirradiated and in vitro–irradiated (2.5 Gy) baboon-mobilized PB CD34⁺ cells were incubated for 7 days in serum-free medium in the presence of 4F. Cell cycle analysis was performed by flow cytometry before and after 1 and 3 days of culture. G₀, G₁, and S/G₂/M cell content was determined using triple labeling with anti-CD34-PE mAb, anti-Ki67-FITC mAb, and 7 AAD. Cell cycle phenotype of gated CD34⁺ cells is shown as a biparametric dot plot. x-axis indicates DNA/7 AAD cell content; y-axis, nuclear protein Ki67 cell content. Lower left quadrant, G₀CD34⁺ cells; upper left quadrant, G₁CD34⁺ cells; upper right quadrant, S/G₂/M CD34⁺ cells. Results are taken from tests on one representative baboon.