Time-course of changes in CFC and 6-week LTC-IC (expressed as LTC-IC–derived CFC) numbers in suspension cultures of CD34⁺CD38⁻ human marrow cells incubated in serum-free medium containing 100 ng/mL FL and SF and 20 ng/mL IL-3, IL-6, and G-CSF with varying amounts of TNF.

0 (X), 0.1 ng/mL (○), 1 ng/mL (○), and 10 ng/mL (●) of TNF added. Values shown are the mean ±SEM of data from 4 to 11 experiments, each with a different marrow source. At each time point, the progeny of 200 (n = 2), 500 (n = 3), or 1000 (n = 6) CD34⁺CD38⁻ cells were analyzed. Input CFC and total LTC-IC–derived CFC values (per 1000 CD34⁺CD38⁻ cells) were 37 ± 10 and 2500 ± 960, respectively.