IL-6

IL-6 is a pleotropic cytokine that regulates the development, proliferation and maturation of a number of hematopoietic cells and is essential for the maturation of B cells into immunoglobulin-secreting cells. IL-6 can also influence the growth and function of non-hematopoietic cells including the differentiation of nerve cells, metabolism of bone and induction of acute phase proteins in hepatocytes.
IL-6 is predominately expressed by T cells, macrophages, fibroblasts, endothelial cells and keratinocytes. IL-6 expression can be stimulated by a number of different factors including, T cell mitogens, LPS, viruses, IL-1, TNF, IL-2, IFN-b, platelet derived growth factor (PDGF), protein kinase C, calcium ionophore A23187 and factors that increase the intracellular concentration of cAMP.
IL-6 is expressed as a glycoprotein with a variable molecular mass as a result of differential glycosylation/phosphorylation patterns. At least six distinct IL-6 phosphoglycoproteins have been identified. The lower molecular weight species, 23- to 25-kDa, are O-glycosylated while the 28- to 30-kDa species are both O- and N-glycosylated.