Figure 6

CCL18 production by monocytes upon stimulation with RA synovial fluid. Panel A. Monocytes/macrophages were cultured for three days. A part of the cells were incubated with IL-10, IL-4 or IL-13 alone (left side of the figure) and another part was incubated with these cytokines in the presence of RA SF (right side of the figure). Half of the latter were also incubated with neutralizing antibodies against IL-10 and IL-13 or both, which is shown by the white, gray and checked bars respectively in panel A. The bars represent the mean CCL18 pg/ml from 6 separate experiments. ND = not detectable. Panel B. The cells were then washed and only the cytokines were added again to the fresh medium. After another 3 days, supernatant was measured again. The left side of the figure shows the CCL18 production upon stimulation with IL-4, IL-13 and IL-10. The right side shows the production upon stimulation with these cytokines by cells that have been pre-incubated with SF for three days, in the presence or absence of anti IL-10, anti IL-13 or both (white, gray and checked bars respectively). ND = not detectable. * represents a p-value of <0,05 (Wilcoxon Signed Rank test). Panel C. The potency of neutralizing antibodies against IL-13 and IL-10 was tested by investigating their ability to inhibit the synergy between IL-13 and IL-10 and IL-4 and IL-10. The bars represent the mean (± SEM) CCL18 secretion (pg/ml).