Interleukin-18-binding protein (IL18BP) is also known as Tadekinig-alfa, IL18BPa, which functions as an IL18 inhibitor. IL18BP is a secreted protein which contains one Ig-like C2-type (immunoglobulin-like) domain. IL18BP does not have a transmembrane domain and hence is not anchored to the cell membrane. IL18BP is strongly expressed in heart, lung, placenta and spleen. Isoform A of IL18BP binds to IL-18 and inhibits its activity. IL18BP also functions as an inhibitor of the early TH1 cytokine response. IL18BP suppresses the production of IFN-gamma resulting in reduced T-helper type 1 immune responses.