a, SPR sensorgrams of human DR-18 (hDR-18) binding to human or cynomolgus macaque (M. fascicularis) IL-18Rα and IL-18BP. b, Concentration–response curves of hIL-18 or hDR-18 on HEK Blue IL-18R reporter cells. c, Titration of hIL-18BP on a fixed concentration of hIL-18 (1 ng/ml) or hDR-18 (0.1 ng/ml) on HEK Blue IL-18R reporter cells. d, e, Concentration–response curves of IFN-γ stimulation by hIL-18 or hDR-18 on human PBMCs (d) or cynomolgus macaque PBMCs (e). IFN-γ concentration measured by ELISA. Data are representative of at least two independent experiments with n = 2 for b–e and presented as mean ± s.e.m.