Interleukin-18 (IL18, also known as interferon-gamma inducing factor or IGIF) is a cytokine that belongs to the IL-1 superfamily and is produced by macrophages and other cells. Its biological activity is pleiotropic and it has been shown to induce interferon-gamma production in KG-1 cells. The combination of this cytokine and IL12 has been shown to inhibit IL4 dependent IgE and IgG1 production, and enhance IgG2a production in B cells.Recombinant rat Interleukin-18 (rrIL-18) produced in E.coli is a single non-glycosylated polypeptide chain containing 159 amino acids. A fully biologically active molecule, rrIL-18 has a molecular mass of 18.4 kDa analyzed by reducing SDS-PAGE and is obtained by proprietary chromatographic techniques at GenScript.