Tumor necrosis factor alpha (TNF-alpha) is a cytokine that binds to the TNF-R1 and TNF-R2 receptors. TNF-alpha is mainly secreted by macrophages and induces cell death of certain tumor cell lines. It is a potent pyrogen causing fever by direct action or by stimulation of IL-1 secretion, and therefore found in cachexia accompanying diverse cancers and infections. Genetic variations in TNF are associated with susceptibility to psoriatic arthritis and to HBV infection.The synthetic peptide used to raise the antibody Cat. No. 251900 is selected from a sequence within the C-term region of human TNF-alpha. For blocking experiments, a 10 to 100 fold molar excess to antibody is recommended.