Figure 6. Transduced RPMI-8226 human myeloma cells express biologically active soluble hRANKL.

A. shRANKL is detected by ELISA (Biomedica Gruppe, Wien, Austria), at a concentration of ∼0.4 ng.ml⁻¹, in medium conditioned using RPMI-8226/hRANKL/eGFP cells, but not in controls. B. Multinucleated TRAP-positive cells (osteoclasts) formed in a culture of mouse PBMC cultured in medium conditioned with RPMI-8226/hRANKL/eGFP, supplemented with M-CSF (50 ng.ml⁻¹). No osteoclasts were observed in control wells containing conditioned media from wild-type cells (data not shown) or RPMI-8226/eGFP. C. Resorption trails formed on the surface of dentine slices cultured in the presence of freshly prepared mouse PBMC, using medium conditioned with RPMI-8226/hRANKL/eGFP. No trails formed on slices cultured in medium conditioned by RPMI-8226/eGFP (or wild-type - data not shown). Statistical analysis performed using unpaired t-test. Data = mean± S.E.M.