Fig. 6.

Bone marrow infiltration by macrophages and multinucleated giant cells in PPT2 knockout mice. (A–D) Hematoxylin/eosin-stained longitudinal sections of bone marrow from age-matched PPT2 knockout and WT mice. Arrows denote multinucleated giant cells. (C and D) High-magnification images corresponding to images in A and B.(E and F) Anti-mac3 immunostaining of macrophages in PPT2 knockout and WT mice. Multinucleated giant cells, seen only in the PPT2 knockout mice, are indicated by arrows. The few large stained cells in the WT marrow (F) are normal megakaryocytes, which also stain with the anti-mac3 Ab but are negative for F4/80, a macrophage-specific marker (data not shown). (G) Autofluorescent storage material (green) in multinucleated giant cells in PPT2 knockout bone marrow. Cell nuclei are stained with Hoechst dye (blue). No significant autofluorescence was seen in control mouse bone marrow (data not shown). b, bone. (Bar = 100 μm.)