Tumor necrosis factor alpha (TNF-α), also known as cachectin and TNFSF1A, is the prototypic ligand of the TNF superfamily (1). It is a pleiotropic molecule that plays a central role in inflammation, immune system development, apoptosis, and lipid metabolism (2-5). TNF-α is also involved in a number of pathological conditions including asthma, Crohn’s disease, rheumatoid arthritis, neuropathic pain, obesity, type 2 diabetes, septic shock, autoimmunity, and cancer (5-11).Human TNF-α is synthesized as a 26 kDa type II transmembrane protein that consists of a 35 amino acid (aa) cytoplasmic domain, a 21 aa transmembrane segment, and a 177 aa extracellular domain (ECD) (12, 13). Within the ECD, human TNF-α shares 97% aa sequence identity with rhesus monkey, and 71-92% aa identity with bovine, canine, cotton rat, equine, feline, mouse, porcine, and rat TNF-α. It is produced by a wide variety of immune, epithelial, endothelial, and tumor cells. TNF-α is assembled intracellularly to form a noncovalently linked homotrimer which is expressed on the cell surface (14). Cell surface TNF-α can both induce the lysis of tumor cells and virus infected cells, and generate its own downstream cell signaling following ligation by soluble TNF RI (15, 16). Shedding of membrane bound TNF-α by TACE/ADAM17 releases the bioactive cytokine, a 55 kDa soluble trimer of the TNF-α extracellular domain (17-19).TNF-α binds the ubiquitous 55-60 kDa TNF RI (20, 21) and the hematopoietic cell-restricted 78-80 kDa TNF RII (22, 23), both of which are also expressed as homotrimers (1, 24). Both type I and type II receptors bind TNF-α with comparable affinity and can promote NFkB activation (25-28). Only TNF RI, however, contains a cytoplasmic death domain which triggers the activation of apoptosis (3, 29). Soluble forms of both types of receptors are released into human serum and urine and can neutralize the biological activity of TNF-α (30-32).The Quantikine Human TNF-α Immunoassay is a 3.5-4.5 hour solid phase ELISA designed to measure human TNF-α in cell culture supernates, serum, and plasma. It contains E. coli-derived recombinant human TNF-α and antibodies raised against this protein. It has been shown to accurately quantitate the recombinant factor. Results obtained with naturally occurring TNF-α samples showed linear curves that were parallel to the standard curves obtained using the Quantikine kit standards. These results indicate that this kit can be used to determine relative mass values for naturally occurring human BAFF.alues for natural human TNF-α.Since the measurement of TNF-α is insensitive to the addition of recombinant forms of either of the two types of soluble receptors, it is probable that this measurement detects the total amount of TNF-α in samples, i.e., the total amount of free TNF-α plus the amount of TNF-α bound to soluble receptors.
This assay recognizes natural and recombinant human TNF-α.The factors listed below were prepared at 50 ng/mL in Calibrator Diluent RD6-35 and assayed for cross reactivity. Preparations of the following factors at 50 ng/mL in a mid-range rhTNF-α control were assayed for interference. No significant cross-reactivity or interference was observed.
Store the unopened kit at 2-8 °C. Do not use past kit expiration date.
Twenty-five assays were evaluated and the minimum detectable dose (MDD) of TNF-α ranged from 0.5-5.5
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About R&D Systems
R&D Systems was founded in 1976 in Minneapolis, MN. It is a wholly owned subsidiary of TECHNE Corporation (a holding company with no employees). TECHNE has two operating subsidiaries: Research & Diagnostics Systems, Inc. (R&D Systems) and R&D Systems Europe Ltd. (R&D Europe). R&D Systems has two operating divisions: Biotechnology, which manufactures reagents primarily for the research market, and Hematology, which manufactures controls and calibrators for hematology analyzers. In July, 2005 R&D Systems purchased BiosPacific, which became a wholly owned subsidiary. BiosPacific is located in Emeryville, CA and consists of a sales force which provides products for development of Immunoassay kits. R&D Systems Europe in Abingdon, England distributes biotechnology products and is the European Representative for the Biotech Division. They received ISO 9001: 2000 certification in June, 2007. R&D Systems Europe has a sales subsidiary, R&D Systems GmBH, in Germany. R&D Systems established a wholly owned subsidiary in the People's Republic of China in May 2007. R&D Systems China Co. Ltd. officially opened its warehouse and distribution center in Shanghai, China on October 1, 2007. R&D China will provide products and marketing and technical support to their Chinese distributors. R&D Systems physical plant includes over 498,460 square feet of laboratory, manufacturing, and office space.