HS/PCs are reduced in the E9.5 to E11.5 HBA in Csf1r-directed DTA depletion. Percentages of (A) viable HBA cells as determined by Hoescht dye exclusion, (B) CD45⁺F4/80⁺CD11b⁺ macrophages, (C) CD31⁺CD45⁻ ECs, and (D) CD45⁺F4/80⁻CD11b⁻ HCs from E9.5 to E11.5 WT and Csf1r-Cre^+/DTA (Cre^+/DTA) littermates in FACS analysis. Each dot or square represents 1 WT or Cre^+/DTA embryo. SEM is shown. n = 3; *P < .05; ***P < .001. (E) CFU-C per ee of HBA cells in E9.5, 10.5, and 11.5 WT and Cre^+/DTA littermates. Colony type is indicated by color bars. E9.5 n = 2; E10.5 n = 3; E11.5 n = 3; *P < .05; ***P < .001. (F) Percentage of donor-cell (Ly5.2) chimerism in the peripheral blood of irradiated (Ly5.1) recipients injected with WT or Cre^+/DTA E11.5 (44 to 48 sp) HBA cells as determined by Ly5.1/Ly5.2 FACS analysis. Eight recipients received WT (1 to 3 ee) and 8 recipients received Cre^+/DTA (1 to 3) HBA cells. Dots and squares indicate individual recipients of WT or Cre^+/DTA cells, respectively, that were examined at 4 and 16 weeks (W) posttransplantation. n = 5.