Effects of Flt3L treatment on EPLM, B lymphopoiesis, and DCs. (A) Effect of Flt3L treatment on EPLM. The left cytograms show the B220 versus CD117 distribution on forward/side scatter-gated bone marrow cells from PBS-injected (top panels) or Flt3L-injected mice (bottom panels). The boxed areas indicate B220⁺CD117^low cells and the figures the percent cells in these areas. The right cytograms show the CD93 versus CD19/NK1.1 distribution on gated B220⁺CD117^low cells and the percent cells in each quadrant. (B) Effect of Flt3L treatment on B lymphopoiesis. Shown are cytogram displays of BM cells from PBS-treated (top panels) or Flt3L-treated (bottom panels) stained with the indicated markers. In each panel, the figures represent the percent cells in each quadrant. (C) Effect of Flt3L treatment on DCs. Shown are cytogram displays of B220 versus CD11c on BM (left) or spleen cells (right) from PBS-(top) or Flt3L-treated mice. The figures in each panel indicate the percent cells in each quadrant. (D) Flt3L dose response. Shown is a summary of the BM (left) or spleen (right) profile of mice treated with 10 daily injections of the indicated dose of Flt3L. Each histogram shows, on a logarithmic scale, the mean ± SD number of cells in the indicated subpopulations from groups of 3 mice. Note the different vertical scale for BM and spleen.