Proliferative potential of HF-derived leukocytes. (A) Large numbers of HF cultures were established in parallel from the intermediate fragments of vibrissal follicles and multiple HF cultures (3-20 in total at each time point) were harvested at the indicated time points. These samples were stained for Lin, c-kit, and Sca-1 to determine the numbers of total Lin^–/c-kit⁺ cells (squares), Lin^–/c-kit⁺/Sca-1⁺ cells (closed circles), and Lin^–/c-kit⁺/Sca-1^– cells (open circles). (B) HF cultures (6-week-old) were double-stained with anti-BrdU mAb and anti–c-kit mAb after 60 minutes of incubation with or without BrdU. (C) Loosely adherent cells were harvested from 5-week-old HF cultures by gentle pipetting and were examined for their proliferative responses to the indicated growth factors. Data shown are the means ± SD of ³H-thymidine uptake (n = 3; *P < .05; **P < .01) on day 3. Results shown in this figure are representative of 2 independent experiments.