IL-7 is important for the normal maintenance of early IL-7 receptor-positive progenitors. (A) Representative FACS plots showing the gating strategies used to identify IL-7R⁺ early progenitor cells (LMPPs and CLPs) among lineage low/negative progenitors from normal (IL-7^+/+) as well as IL-7–deficient (IL-7^−/−) mice, as indicated. The percentages in the gates are mean percentages of total BM-nucleated cells. LIN cocktail contains antibodies against CD11b, GR1, TER119, CD3, CD11c, NK1.1, CD19, and CD45R/B220. (B) Absolute numbers of the total cellularity, IL-7R⁻LMPPs, IL-7R⁺LMPPs and CLPs in the BM (femurs, tibias, and crista iliac) of wt and IL-7–deficient mice (n = 6 of each genotype). Each dot represents the number from an individual mouse, and the horizontal line represents the mean in each group. Unpaired t test was used to compare the difference between wt and IL-7^−/− mice. Data are collected from 2 independent experiments.