[Tumor necrosis factor alpha (cachectin). Biological properties and role in physiopathology]

Cachectin, or TNF-alpha (tumor necrosis factor alpha) was first described as a product of activated monocytes capable of inducing tumor cell lysis both in vitro and in vivo. In addition to this activity, TNF-alpha has been shown to possess many other biological properties: it modulates the synthesis of the enzymes involved in lipogenesis and regulates the function of various types of normal cells, such as fibroblasts, osteoblasts, endothelial cells and adipocytes. Moreover, TNF-alpha - displays multifunctional immunoregulatory activity on T and B lymphocytes and on natural killer and lymphokine activated killer cells and plays a major role in the defence against infections and in the immune response against cancer. In severe infection or cancer, an excessive production of TNF-alpha may be responsible for septic shocks or cachexia in both animals and man. The high conservation of the TNF-alpha gene in all species despite its toxicity indicates that it plays a crucial but still partially understood role.