ADAM-9 mediates IL-6 production by human osteoblasts in an α_vβ₅-integrin–dependent manner. (A) Human osteoblasts were cultured in the presence or absence of recombinant ADAM-9 and either a control IgG or the presence of blocking antibodies to different integrins. (B) Human osteoblasts were cultured in the presence or absence of RPMI-8226 myeloma cells and either a control IgG or the presence of ADAM-9–blocking antibody. (C) Human osteoblasts were cultured in the presence or absence of RPMI-8226 cells and either an IgG control antibody or antibodies to various integrins. In each case, after 24 hours, IL-6 was measured by ELISA. Data are the means of samples from a representative experiment (n = 4-8), and error bars are 95% CI. IL-6 production is shown as percentage of the mean + 95% CI of the maximum bar in the graph. A Mann-Whitney U test was used for pair-wise comparisons. ^*P < .01 compared with hOBs alone; and †P < .01 compared with IgG.