TNF activation negatively regulates maintenance of cycling CB CD34⁺CD38⁻ LTC-ICs.

The 150 freshly isolated CD34⁺ (A) or 25 to 75 CD34⁺CB38⁻ CB cells (B), or their EEs following 5 to 7 days of culture in KFT3 in the absence or presence of TNF were evaluated for 6-week LTC-CFC activity, as described in “Materials and methods.” Data are presented as mean values of 2 to 3 replicates of each group for CD34⁺ CB cells (panel A; 3 experiments) and CD34⁺CD38⁻ CB cells (panel B; 3 experiments).