Cell-intrinsic requirement for C/EBPβ in monopoiesis. (A) Lethally irradiated CD45.1⁺ mice were reconstituted with BM cells obtained from CD45.2⁺ WT or Cebpb^−/− mice. Flow cytometric analyses of monocyte subsets among CD45.2⁺ lineage⁻ CD11b⁺ CD115⁺ cells in the recipients are shown in the left panel, and the frequencies of the indicated population are shown in the right panel (n = 7 for WT donors and n = 6 for Cebpb^−/− donors). (B) BM cells of Mx1-Cre⁺Cebpb^f/f or Mx1-Cre^–Cebpb^f/f mice (CD45.2) were transplanted into lethally irradiated mice (CD45.1). Flow cytometric analysis of monocyte subsets among CD45.2⁺ lineage⁻ CD11b⁺ CD115⁺ cells in recipient mice is shown in the left panel. The frequencies of monocyte subsets in the BM and PB are shown in the right panel (n = 8). Data are presented as the mean ± SD. **P < .01, ***P < .001. Numbers indicate the percentage of cells in the adjacent boxed area. FSC, forward scatter.