Interleukin 8

Interleukin-8 (IL-8) is a chemokine produced by macrophages and other cell types such as epithelial cells. It is also synthesized by endothelial cells, which store IL-8 in their storage vesicles, the Weibel-Palade bodies.

Toll-like receptors are the receptors of the innate immune system. These receptors recognize antigen patterns (like LPS in gram negative bacteria). Through a chain of biochemical reactions IL-8 is secreted and is an important mediator of the immune reaction in the innate immune system response.

It is also secreted in urinary tract infections.

Function
IL-8 can be secreted by any cells with toll-like receptors which are involved in the innate immune response. IL-8's primary function is to recruit neutrophils to phagocytose the antigen which trigger the antigen pattern toll-like receptors.

When first encountering an antigen, the primary cells to encounter it are the macrophages who phagocytose the particle. Upon processing, they release chemokines to signal other immune cells to come in to the site of inflammation. IL-8 is one such chemokine. It serves as a chemical signal that attracts neutrophils at the site of inflammation, and therefore is also known as Neutrophil Chemotactic Factor.

Clinical significance
If a pregnant mother has high levels of interleukin-8, she has a higher risk of inducing schizophrenia in her offspring. High levels of Interleukin 8 have been shown to reduce the chance of good treatment responses to antipsychotic medication in schizophrenia.

Interleukin-8 is often associated with inflammation.

Nomenclature
IL-8 was renamed CXCL8 by the Chemokine Nomenclature Subcommittee of the Nomenclature Committee of the International Union of Immunological Societies, although its approved gene symbol remains IL8.