Osteoclast differentiation of properdin-deficient and wild-type bone-marrow precursors. (A) BM cells from control and CAIA mice (WT and KO) were differentiated for 7 days, and the number of mature osteoclasts was determined after specific TRAP staining. The graph shows the mean ± SD of TRAP-positive cells from three experiments with three sample repeats/group. ***P < 0.001; Student t test. One representative experiment is shown on the photos captured by a Nikon camera at a magnification of ×100 and for photo insert of ×400 of light-microscope lens. (B) TRAP-positive cells in BM cultures generated in the presence of blocking antibody against RANKL (blocking RANKL). The graph shows the mean ± SD of TRAP-positive cells in CAIA WT and KO cell cultures from three separate experiments with three sample repeats/group. **P < 0.01; Student t test. One individual experiment is shown on the photos taken at magnification ×100 with a light-microscope lens.