Tumor necrosis factor alpha (TNF-alpha), is the prototypic ligand of the TNF superfamily. It is a pleiotropic molecule that plays a central role in inflammation, apoptosis, and immune system development. TNF-alpha is produced by a wide variety of immune and epithelial cell types. It belongs to the TNF family of ligands and signals through two receptors, TNFR1 and TNFR2. TNF-alpha is cytotoxic to a wide variety of tumor cells and is an essential factor in mediating the immune response against bacterial infections. TNF-alpha also plays a role in the induction of septic shock, auto immune diseases, rheumatoid arthritis, inflammation, and diabetes.