IL-1Ra is the natural antagonist of the pro-inflammatory cytokines Interleukin-1? and Interleukin-1?. IL-1Ra is produced by a variety of cells including monocytes, macrophages, neutrophils and fibroblasts in response to the binding of various pro-inflammatory cytokines. IL1Ra Human Recombinant produced in E.Coli is single, a non-glycosylated, Polypeptide chain containing 152 amino acids fragment (26-177) and having a total molecular mass of 21.63kDa with an amino-terminal hexahistidine tag.The IL-1Ra His is purified by proprietary chromatographic techniques.