Description
IL8 is produced by stimulated monocytes but not by tissue macrophages and T-lymphocytes. In many cell types the synthesis of IL8 is strongly stimulated by IL1 and TNF-alpha. In human skin fibroblasts the expression of IL-8 is enhanced by Leukoregulin.The expression of IL-8 from resting and stimulated human blood monocytes is up-regulated by IL-7. In chondrocytes the synthesis of IL8 is stimulated by IL1-beta TNF-alpha and bacterial lipopolysaccharides. In human astrocytes the synthesis and secretion of IL8 is induced by IL-1 and TNF-alpha. The IL8 receptor is a dimeric glycoprotein consisting of a 59 kDa and a 67 kDa subunit. It has been given the name CD128. It is expressed in many different cell types including those not responding to IL8. The biological activities of IL8 resemble those of a related protein, NAP-2. IL8 differs from all other cytokines in its ability to specifically activate neutrophil granulocytes. In neutrophils IL8 causes a transient increase in cytosolic calcium levels and the release of enzymes from granules. IL-8 also enhances the metabolism of reactive oxygen species and increases Chemotaxis and the enhanced expression of adhesion molecules. A pre-activation by IL3 is required to render basophils and neutrophils susceptible to further activation by IL8