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, TNF-alpha and bacterial lipopolysaccharides. The expression of IL8 from resting and stimulated human blood monocytes is up-regulated by IL7. The IL8 receptor (CD128) is a dimeric glycoprotein consisting of a 59 kDa and a 67 kDa subunit. It is expressed in many different cell types including those not responding to IL8. IL8 differs from all other cytokines in its ability to specifically activate neutrophil granulocytes. IL8 also enhances the metabolism of reactive oxygen species and increases chemotaxis and the enhanced expression of adhesion molecules. Recombinant Human IL8 (77aa) represents the construct spanning residues 23 to 99, inclusive.