osteoclast formation and expressions of the receptors. (A) CD14+ monocytes isolated from the PBMCs from healthy donors were cultured for 7 days with M-CSF plus RANKL, or M-CSF alone to generate osteoclasts and macrophages. The induced osteoclasts (the left photo) and macrophages (the right photo) were fixed and stained for TRAP. TRAP-positive cells appeared as red cells. Scale bar, 100 μm. (B) CD14+ monocytes isolated from the PBMCs from healthy donors were cultured for 10 days with M-CSF plus RANKL, or M-CSF alone on calcium phosphate-coated wells. After removing the cells, formed pits (white area) were observed by microscopy. Scale bar, 300 μm. (C) Osteoclasts (OC) and macrophages (Mph) induced by 7 days culture of CD14+ cells with M-CSF plus RANKL or M-CSF alone were harvested and immunostained with anti-CD4, CXCR4, CCR5, CD14, and CD71 antibodies and analyzed by FACS. Pink histograms represent the cells stained with antibodies against each receptor. Green histograms represent the cells stained with each isotype-matched control antibody.