IL-18 Background
IL-18 is a proinflammatory cytokine that belongs to the IL-1 family of ligands. Macrophages and dendritic cells are the primary sources for active IL-18, but the IL-18 precursor is constitutively expressed in epithelial cells throughout the body. Similar to IL-1beta, IL-18 is synthesized as an inactive precursor requiring processing by caspase-1 into an active cytokine. But unlike IL-1beta, the IL-18 precursor is constitutively present in nearly all cells in healthy humans and animals. The IL-18 receptors, although distinct from IL-1 receptors, also belong to the IL-1 receptor family. The IL-18 receptor (IL-18R) complex consists of two receptor chains; a ligand-binding chain termed the IL-18Ralpha chain and a co-receptor termed the IL-18Rbeta chain; both chains are required for signaling (Ref.1 and 2).
IL-18 Activity
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