Figure 4.

Titration of human and murine IL-18BP isoforms on human IL-18 activity. Human and murine isoforms were incubated with human IL-18 (20 ng/ml) for 30 min at increasing concentrations using 2-fold dilutions of IL-18BP. After this incubation, the mixtures were added to NKO cells cocultured with IL-12 (2 ng/ml). After 24 h IFN-γ was measured. The stimulation control of IL-12 (2 ng/ml) plus IL-18 (20 ng/ml) with purified supernatants from mock-transfected COS cells was set at 100%, and the percent change was calculated for each concentration of IL-18BP isoforms tested.