This ELISA is designed for the quantitative determination of TNFα. This ELISA is for research use only. In a first incubation step, TNFα is bound to monoclonal antibodies, which are immobilised on the surface of the microtiter plate. After a washing step to remove all interfering substances, a biotinylated antibody is added. After another washing step, a horseradish peroxidase-labelled conjugate is added. The amount of the converted substrate by the peroxidase is directly proportional to the amount of bound TNFα and can be determined photometrically at 450 nm. A dose response curve of the absorbance unit (optical density, OD at 450 nm) vs. concentration is generated, using the values obtained from the standard. TNFα, present in the samples, is determined directly from this curve. Sample Types: stool. Range: 10-500 pg/mL. Sensitivity: 10 pg/mL. Time: 4.5 hours ? Tumor necrosis factor-alpha (TNFα) is a cytokine involved in systemic inflammation. The primary role of TNFα is in the regulation of immune cells. TNFα stimulates the acute phase reaction, induces apoptotic cell death, cellular proliferation and differentiation,inhibits tumor genesis and viral replication. Dysregulation of TNFα production has been implicated in a variety of human diseases like cancer and Alzheimers. TNF Alpha is secreted by macrophages, monocytes, neutrophils, T-cells as well as natural killer cells following their stimulation by bacterial lipopolysaccharides. Human TNFα is a non-glycosylated protein with a molecular weight of 17.5 kDa and a length of 157 amino acids. TNFα shows a wide spectrum of biological activities. It causes cytolysis and/or cytostasis of many tumor cell lines in vitro. Within hours after injection, TNFα leads to destruction of small blood vessels within malignant tumors. TNFα enhances phagocytosis and cytotoxicity in neutrophilic granulocytes and modulates the expression of many other proteins. Elevated TNFα serum levels are found in patients suffering from Crohn's disease, ulcerating colitis or rheumatoid arthritis.