Recruitment of candidate murine stem cells into proliferation. Lin⁻Sca1⁺c-kit⁺ BM cells were plated at 1 cell per well in SF-medium (X-vivo 15 with 0.5% detoxified BSA) supplemented with indicated cytokines at 50 ng/mL each, except for IL-3 (20 ng/mL). The cocktail contained the following 7 cytokines: GM-CSF, KL, IL-3, IL-6, MGDF, FL, and G-CSF. The total number of clones (containing 2 or more cells) and large colonies (clones covering more than 50% of well) were scored after 10 days of incubation. 0 = no clones. Results are presented as the means (±SEM) of 4 separate experiments. Paired Student's t-test was performed comparing KFM with the other cytokine combinations presented. *P < .05; **P < .005.