Expression Of Recombinant Human IL-6 Mature Peptides In E.coli And Detection Of HIL-6 Biological Activity

Interleukin 6 (IL-6) is a pleiotropic cytokine that is produced by many different cell types such as Monocytes/macrophages, Fibrobalsts, endothelial.The human IL-6 gene has a length of approximately 5 kb and contains five exons and four introns. It maps to human chromosome 7p21 between the markers D7S135 and D7S370.Human IL-6 is a protein of 186 amino acids glycosylated at positions 73 and 172. It is synthesized as a precursor protein of 212 amino acids. At least five different molecular forms of IL-6 with molecular masses from 21 to 28 kDa are expressed in different cells. This difference is derived from posttranslational alterations such as glycosylation and phosphorylation.The IL-6 receptor consists of two subunits: theαchain (IL-6R), an 80 kDa transmembrane glycoprotein which binds IL-6 with low affinity, and theβchain (gp130), a 130 kDa transmembrane glycoprotein,originally identified as a signal-transducing subunit for IL-6 receptor (IL-6R), which binds to the IL-6-IL-6R heterodimer to form the high-affinity signal transducing complex. The functional redundancy observed among these IL-6-related cytokine subfamily is mostly explained by the sharing of receptor subunit gp130 among the IL-6 cytokine family.A complex of IL-6 and a soluble form of IL-6Rαcan activate signal transduction in cells expressing only the gp130 receptor subunit. Two additional distinct classes of IL-6 mutant will lead to bind to the IL-6 receptor but fail to generate signals.