LPS induced “osteoclast-like” cells formation. A and B, examples (A) and number (B) of multinucleated TRAP-positive cells formed in M-CSF-, M-CSF/sRANKL-, M-CSF/LPS-, and M-CSF/sRANKL/LPS-treated cultures after 14 days of culture. sRANKL was added at day 7, and LPS was added either at day 7 or day 10. C, expression of cathepsin K, OSCAR, and the calcitonin receptor (CT-R) in response to osteoclastogenic mediators. **, p < 0.01 compared with M-CSF alone; ##, p < 0.01 compared with M-CSF/sRANKL-treated cultures. Error bars = S.E.