title: Interleukin-18.
abstract: Interleukin-18 (IL-18), a recently described member of the IL-1 cytokine superfamily, is now recognized as an important regulator of innate and acquired immune responses. IL-18 is expressed at sites of chronic inflammation, in autoimmune diseases, in a variety of cancers, and in the context of numerous infectious diseases. This short review will describe the basic biology of IL-18 and thereafter address its potential effector and regulatory role in several human disease states including autoimmunity and infection. IL-18, previously known as interferon-gamma (IFN-gamma)-inducing factor, was identified as an endotoxin-induced serum factor that stimulated IFN-gamma production by murine splenocytes [(1) ]. IL-18 was cloned from a murine liver cell cDNA library generated from animals primed with heat-killed Propionibacterium acnes and subsequently challenged with lipopolysaccharide [(2) ]. Nucleotide sequencing of murine IL-18 predicted a precursor polypeptide of 192 amino acids lacking a conventional signal peptide and a mature protein of 157 amino acids. Subsequent cloning of human IL-18 cDNA revealed 65% homology with murine IL-18 [(3) ] and showed that both contain an unusual leader sequence consisting of 35 amino acids at their N terminus.
authors.affiliation: Centre for Rheumatic Diseases, University of Glasgow, 10 Alexandra Parade, Glasgow G31 2ER, Scotland, UK.
authors.forename: J Alastair
authors.initials: JA
authors.lastname: Gracie
authors.forename: Susan E
authors.initials: SE
authors.lastname: Robertson
authors.forename: Iain B
authors.initials: IB
authors.lastname: McInnes
mesh_terms: D000818:Animals; D001327:Autoimmune Diseases / Q000276:immunology; D005786:Gene Expression Regulation; D006801:Humans; D007239:Infections / Q000276:immunology; D007249:Inflammation / Q000276:immunology; D020382:Interleukin-18 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology*; D053727:Interleukin-18 Receptor alpha Subunit; D018123:Receptors, Interleukin / Q000502:physiology; D053724:Receptors, Interleukin-18
chemical_list: C508572:IL18R1 protein, human; D020382:Interleukin-18; D053727:Interleukin-18 Receptor alpha Subunit; D018123:Receptors, Interleukin; D053724:Receptors, Interleukin-18