= Tumor necrosis factor
= TNF
{c}
{synonym}
= TNF-alpha
{c}
{synonym}
<Tumor necrosis factor>, abbreviated <TNF> and also called <TNF-alpha>, is a signalling <cytokine> acting through <cell-surface receptors>. It occurs in membrane-associated and soluble forms, is produced prominently by <macrophages>, and can induce <cell death> in susceptible tumour <cells>. The biological outcome depends on the responding <cells> and signalling context.<Tumor necrosis factor in UniProt>[P01375, protein names, processed forms and FUNCTION]{ref}
Its name records an experimental discovery. In1975, investigators found that <blood serum> from mice first infected with BCG and then treated with <endotoxin> could cause <necrosis> in transplanted <tumours>. Tests indicated that the active material was a host-derived factor, rather than residual <endotoxin>. The authors proposed release from <macrophages>; that proposed cellular origin should be distinguished from their directly observed serum activity.<An endotoxin-induced serum factor that causes necrosis of tumors by E. A. Carswell and others>[Abstract, serum-transfer observations and origin interpretation]{ref}
An illuminating comparison was the different response of cultures: the preparation was toxic to two tested neoplastic cell lines but not to mouse embryo cultures. This separates a measurable activity from a universal property of all <cells>. The historical <tumour> assay identified a signalling substance; it did not establish that <TNF> kills every <tumour> or has only one physiological role.<An endotoxin-induced serum factor that causes necrosis of tumors by E. A. Carswell and others>[Abstract, in-vitro comparisons]{ref}
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