Cytokine responsiveness of progeny derived from FL + IL-7–stimulated Lin^−/loSca1⁺c-kit⁺ cells. Lin^−/loSca1⁺c-kit⁺ cells were cultured in the presence of FL + IL-7. After 7 or 12 days, cells were harvested, washed, and stimulated with the indicated cytokines for an additional 3 days before ³H-thymidine incorporation was determined (Materials and Methods). The data represent the mean (+SEM) of 3 experiments, in which KL + FL + IL-7–induced³H-thymidine uptake was used as a control (100%) in each experiment.