Interleukin-6 (IL-6) is a multifunctional protein originally discovered in the media of cells stimulated with double stranded RNA. Interleukin-6 (IL-6) induces multiple effects, as indicated by its numerous synonyms: plasmacytoma growth factor, interferon-β-2, monocyte derived human B cell growth factor, B cell stimulating factor, hepatocyte stimulating factor, Interleukin Hybridoma/Plasmacytoma-1. Recombinant human Interleukin-6 (IL-6) that is produced in E. coli and purified by proprietary chromatographic techniques is a single, non-glycosylated polypeptide chain containing 185 amino acids and having a molecular mass of 21,000 Da.