Fig. 4.

IL-8 promotes the formation of OCLs during RANKL inhibition with anti-RANKL Ab. (A) CD14⁺ cells from PBMCs of healthy donors were cultured under the following conditions: M-CSF (50 ng ml⁻¹) and RANKL (125 ng ml⁻¹), M-CSF with anti-RANKL Ab (5 µg ml⁻¹) with or without IL-8 (10 ng ml⁻¹). Ten days after culture, TRAP staining was performed on each culture. Representative images (A) from five healthy donors are shown. (B) The number of OCLs per well in each culture condition was counted (n = 5). (C, D) Pit assays were performed and resorption pit area per a focus was measured on the same cultures. (E) Expression of cathepsin K was evaluated by immunofluorescence staining in the same cultures (cathepsin K-PE and DAPI). Statistical significance was evaluated using one-way ANOVA with Tukey’s post hoc test (B) and paired Student’s t-test (D). aRANKL Ab, anti-RANKL antibody.