From Wikipedia, the free encyclopedia
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.
In humans, the interleukin-8 protein is encoded by the IL8 gene.
There are more receptors of the surface membrane capable to bind
IL-8. The most frequently studied types are the G protein coupled serpentine
receptors CXCR1 and CXCR2. Expression and
affinity to IL-8 is different in the two receptors (CXCR1 >
CXCR2). 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
The protein encoded by this gene is a member of the CXC
chemokine family. This chemokine is one of the major mediators of
the inflammatory response. This chemokine is secreted by several
cell types. It functions as a chemoattractant, and is also a potent
angiogenic factor. Both monomer and homodimer forms of IL-8 were reported as
potent inducers of CXCR1 and CXCR2, the homodimer proved to be more
potent, however, methylation of Leu25 can block activity of
the dimers. IL-8 is believed to play a role in the pathogenesis of
common respiratory tract disease caused by viral infection. This
gene and other ten members of the CXC chemokine gene family form a
chemokine gene cluster in a region mapped to chromosome 4q.
Primary function of IL-8 is the induction of chemotaxis in its target
cells (e.g. neutrophil granulocytes). In neutrophils series of
cell-physiological responses required for migration and its target
function phagocytosis are also induced like increase of
intracellular Ca2+, exocytosis (e.g. histamine release), respiratory
burst. 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
While neutrophil granulocytes are the primary target cells of
IL-8 there is a relative wide range of cells (endothelial cells, macrophages, mast cells, keratinocytes) responding to this
chemokine, too. The chemoattractant activity of IL-8 in similar
concentrations to vertebrates was proved in Tetrahymena pyriformis, which refers to a
phylogenetically well conserved structure and function in the case
of this chemokine.
Interleukin-8 is often associated with inflammation. As an
example, it has been cited as a proinflammatory mediator in gingivitis and psoriasis.. The fact that
Interleukin-8 secretion is increased by oxidant stress and
conversely, Interleukin-8, by causing recruitment of inflammatory
cells induces a further increase in oxidant stress mediators, makes
it a key parameter in localized inflammation.
If a pregnant mother has high levels of interleukin-8, she has a
higher risk of inducing schizophrenia in
High levels of Interleukin 8 have been shown to reduce the chance
of good treatment responses to antipsychotic medication in
IL-8 was renamed CXCL8 by the Chemokine Nomenclature
Subcommittee of the International
Union of Immunological Societies,
although its approved HUGO gene symbol remains
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1icw: INTERLEUKIN-8, MUTANT WITH GLU 38 REPLACED
BY CYS AND CYS 50 REPLACED BY ALA
1ikl: NMR study of monomeric human interleukin-8
(minimized average structure)
1ikm: NMR study of monomeric human interleukin-8
1il8: THREE-DIMENSIONAL STRUCTURE OF INTERLEUKIN 8
1ilp: CXCR-1 N-TERMINAL PEPTIDE BOUND TO
1ilq: CXCR-1 N-TERMINAL PEPTIDE BOUND TO
INTERLEUKIN-8 (MINIMIZED MEAN)
1qe6: INTERLEUKIN-8 WITH AN ADDED DISULFIDE
BETWEEN RESIDUES 5 AND 33 (L5C/H33C)
2il8: THREE-DIMENSIONAL STRUCTURE OF INTERLEUKIN 8
3il8: CRYSTAL STRUCTURE OF INTERLEUKIN 8:
SYMBIOSIS OF NMR AND CRYSTALLOGRAPHY