IL-18
IL-18 (interleukin 18, also known as IGIF, IL1F4 and IL-1g) is a pro-inflammatory cytokine of the IL-1 family. It drives Th1 and natural killer cell responses, stimulates interferon gamma production and contributes to epithelial barrier repair. Browse Assay Genie's current range of IL-18 research reagents below, or read on for the biology behind the target.
IL-18 is a pro-inflammatory cytokine involved primarily in epithelial barrier repair and in polarised T-helper 1 (Th1) and natural killer (NK) cell immune responses. On binding to IL18R1 and IL18RAP it forms a signalling ternary complex that activates NF-kappa-B, triggering synthesis of inflammatory mediators. It acts in synergy with IL-12 to induce interferon gamma (IFNG) synthesis from Th1 and NK cells, and it can regulate both Th1 and Th2 responses.
The protein is constitutively present as an inactive precursor in the cytoplasm of a variety of cells, including macrophages and keratinocytes. Caspase-1 processes the precursor into its active form. The mature cytokine is released into the extracellular milieu by passing through the gasdermin-D (GSDMD) pore, which places IL-18 in the transduction of inflammation downstream of pyroptosis. Alternatively spliced transcript variants of the IL18 gene encode different isoforms.
IL-18 was first described as interferon-gamma-inducing factor, hence the alias IGIF and the earlier HGNC name "interleukin 18 (interferon-gamma-inducing factor)". Other aliases include IL1F4 and IL-1g, reflecting its place in the IL-1 family. The cytokine has been implicated in injury of different organs and in potentially fatal conditions characterised by a cytokine storm, which makes it a frequent subject in inflammation research. Mouse and rat orthologues are both designated Il18.
IL-18 is activated by caspase-1 and released through the GSDMD pore, so it is a key readout of inflammation downstream of pyroptosis.
IL-18 works with IL-12 to induce IFNG synthesis from Th1 and NK cells, shaping polarised immune responses.
The cytokine has been implicated in injury of different organs and in potentially fatal conditions characterised by a cytokine storm.
IL-18 is primarily involved in epithelial barrier repair, and the precursor is found constitutively in cells such as keratinocytes.
IL-18 is a pro-inflammatory cytokine involved in epithelial barrier repair and in Th1 and NK cell responses. After binding IL18R1 and IL18RAP it activates NF-kappa-B, and together with IL-12 it induces interferon gamma synthesis from Th1 and NK cells.
IL-18 is made as an inactive precursor in the cytoplasm of cells such as macrophages and keratinocytes. Caspase-1 processes it into the active form, and the mature cytokine is released extracellularly through the gasdermin-D pore during pyroptosis.
IL-18 is also called IGIF (interferon-gamma-inducing factor), IL1F4 and IL-1g, and it belongs to the IL-1 family. Mouse and rat both have an Il18 orthologue. Check the datasheet of any product for its validated reactivity.
Other IL-1 family members, IL-12 and further interleukins involved in inflammation and T-cell responses.
Gene and protein annotations from HGNC, NCBI Gene and UniProt Q14116; product specifications from Assay Genie datasheets.