Human Interleukin 1 family member 7 (IL-1F7), also named FIL-1 zeta, IL-37, IL-1H4, IL-1HL and IL-1RP1, is an anti-inflammatory member of the IL-1 cytokine family. IL-1F7 shares ~21%, 24%, and 30% aa sequence identity with mature IL-1alpha, IL-1beta and IL-1ra, respectively. Mouse IL-1F7 has not been reported, but human IL-1F7 is active on mouse cells. Five isoforms (IL-1F7a through e) are generated through alternative exon usage and have distinct expression profiles. Like IL-1alpha, IL-1beta and IL-18, all of the IL-1F7 variants lack a typical signal peptide. The longest IL-1F7 transcript is the basis for the product offered here. This product, also referred to as IL-1F7b, or IL-1F7 isoform 1, is normally generated from a 218 amino acid (aa) proprotein that consists of a 45aa propeptide plus a 173 aa mature region that is cleaved by caspase-1 to generate the 32kD mature form (aa46-218). IL-1F7 is up-regulated by inflammatory stimuli in peripheral blood mononuclear cells. Experimental overexpression of IL-1F7b in vivo limits the inflammatory response and protects mice from colitis and LPS-induced shock. Both unprocessed and mature IL-1F7b can form homodimers in solution. Although IL-1F7b will bind to IL-18 Ralpha with low affinity, this has no effect on IL-18 receptor activity. Alternatively, IL-1F7b will also bind to IL-18 BP, generating a complex that interacts with IL-18Rbeta. This has the effect of attenuating IL-18 activity via the IL-18 receptor. IL-1F7b can also function intracellularly. Following LPS-induced cleavage of its propeptide, IL-1F7b associates with Smad3 and translocates to the nucleus. This results in a reduction of pro-inflammatory cytokine secretion.
E. coli derived recombinant protein corresponding to Val46-Asp218 of human IL-37b/IL-1F7b.
Activity:Measured by its ability to enhance IL-18 BP inhibition of IL18 induced IFNgamma release by KG-1 human acute myelogenous leukemia cells (Bufler, P. et al. (2002) PNAS 99:13723). The ED50 for this effect is typically 2.5-12.5ug/ml.
Storage and Stability:Lyophilized powder may be stored at -20°C. Stable for 12 months at -20°C. Reconstitute with sterile PBS, containing at least 0.1% human or bovine serum albumin. Aliquot to avoid repeated freezing and thawing. Store at -20°C. Reconstituted product is stable for 6 months at -20°C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.
