Recombinant IL-18 protein, Human: Product Information
- Purity—more than 85% as established by SDS-PAGE
- Activity—IL-18 protein is quantified by its potential to promote IFN-gamma secretion by KG-1 human acute myelogenous leukemia cells in the presence of TNF-alpha. For this effect, the ED50 is usually 15 to 75 ng/mL.
- Protein construction—a DNA sequence that encodes the human IL18 (NP_001553.1) (Tyr37-Asp193) was expressed
- Expressed host—Escherichia coli
- Predicted N terminal—Tyr 37
- Molecule mass—the recombinant human IL18 contains 157 amino acids and has an estimated molecular mass of 18.2 kDa.
- Formulation—lyophilized from sterile PBS, pH 7.4. Customers can contact Sino Biological for unique requirements or any concerns. Typically, 5% to 8% mannitol and trehalose, and 0.01% Tween80 are added as protectants prior to lyophilization. Customers can refer to the particular buffer data given in the hard copy of CoA.
- Shipping—generally, recombinant proteins are offered as lyophilized powders that are delivered at ambient temperatures. Large packages of recombinant proteins are offered as frozen liquid and are delivered with blue ice, unless customers specify otherwise.
- Stability and storage—specimens are stable for up to one year from the date of receipt at −20℃ to −80℃. They should be stored under sterile conditions at −20℃ to −80℃. It is advised to aliquot the protein for optimal storage. Repeated freeze-thaw cycles should be avoided.
- Reconstitution—a hardcopy of COA with reconstitution instruction is delivered together with the products. Customers can refer to it for complete information.
Recombinant IL-18 protein, Human : Images
Image Credit: Sino Biological US Inc.
Measured by its ability to induce IFN-gamma secretion by KG‑1 human acute myelogenous leukemia cells in the presence of TNF-alpha. The ED50 for this effect is typically 15–75 ng/mL. Image Credit: Sino Biological US Inc.
Interleukin-18 (IL-18), also called interferon-gamma inducing factor, is a proinflammatory cytokine that forms part of the IL-1 superfamily and is synthesized by various cells, including macrophages.
IL-18 can induce the IFN-gamma generation of T cells. IL-18, combined with IL12, has been demonstrated to suppress the production of IL4-reliant IgG1 and IgE and also improves IgG2a production of B cells.
The IL-18-binding protein, or IL18BP for short, can particularly interact with this cytokine and, therefore, adversely controls its biological function. It was observed that IL-18—an IL-1-like cytokine that needs cleavage with caspase-1 to become intense—increases the production of IgE in an IL-4-, CD4+ T cell- and STAT6-dependent manner.
Stimulation mediated by the T cell receptor and IL-18 could cause naive CD4+ T cells to change into IL-4-generating cells in vitro. IL-18 and caspase-1 may be crucial in the regulation of in vivo IgE production, offering a promising treatment target for allergic diseases.
The production of IL-18 in purified synovial fibroblasts and primary synovial cultures was, consequently, up-regulated by IL-1β and TNF-α, indicating that the expression of monokine can provide feedback to support the development of Th1 cells in the synovial membrane.
Synergistic combinations of IL-12, IL-15, and IL-18 may be significant in preserving Th1 responses as well as the production of monokine in RA.
- Dinarello CA. (1999) IL-18: A TH1-inducing, proinflammatory cytokine and new member of the IL-1 family. J Allergy Clin Immunol. 103: 11-24.
- Takeda K, et al. (1998) Defective NK cell activity and Th1 response in IL-18-deficient mice. Immunity. 8(3): 383-90.
- Gracie JA, et al. (1999) A proinflammatory role for IL-18 in rheumatoid arthritis. J Clin Invest. 104(10): 1393-401.