M-CSF and RANKL induce transdifferentiation of immature DCs into OCs. (A) Surface phenotype of human immature monocyte-derived DCs. Dotted lines represent isotypic control. (B) Allostimulatory and synstimulatory properties of immature monocyte-derived DCs cultured for 12 hours in the presence of T cells purified from 2 allogeneic donors (bold lines, ▴ or ♦) or 2 syngeneic donors (dashed lines, • or ▪), respectively. (C) Monocytes (Mo), dendritic cells (DC), and DC-derived OC (DC-OC) are shown in culture (top row) and after TRAP activity detection (middle row). Microscopic pictures of dentine slices show resorptive capacities of these 3 cell types (bottom row). Percentages of total dentine slice surface resorbed are indicated on each picture in the bottom row. The insert shows the resorption tracks at higher magnification (×320). (D) F-actin, αvβ3 integrin and cathepsin K staining on permeabilized DCs-OCs versus monocyte-derived OCs (Mo-OC). Results are from more than 10 experiments.