Sections of murine fetal liver (day E13.5) and bone marrow (6-day postnatal) were stained with CD11b (Mac-1α) antibody–horseradish peroxidase (HRP) (brown) and counterstained with methyl green.

(A) Wild-type fetal liver. (B) Mll-AF9 fetal liver. (C) Wild-type 6-day postnatal bone marrow. (D) Mll-AF9 6-day postnatal bone marrow. Original magnification, × 20.