The effect of TNF on growth of CD34⁺CD38⁻ CB cells at the single cell level.

CD34⁺CD38⁻ CB cells were plated at one cell/well in SF medium supplemented with KFT3 (as described in “Materials and methods”) in the absence (open bars) or presence (black bars) of TNF (20 ng/mL). Cultures were scored for clonal size (from 3 cells to 100% of well covered by cells) and total number of positive wells as indicated following 10 to 12 days of culture. Each group consisted of 120 wells, and results presented are mean values (SEM) from 4 independent experiments.