TNF-$\alpha$

TNF-$\alpha$ appears to be very important. It is release systemically early on and is responsible for cachexia, the old description of TNF-$\alpha$ is cachectin. Macrophages, Kupfer cells, natural killer cells and lymphocytes produce TNF-$\alpha$. The half life is 16 minutes. Plasma levels normally do not exceed 35 picogrammes/Litre. A slight increase in TNF-$\alpha$ induces cell proliferation and differentiation and regulation of cytokine interaction. Higher levels result in tissue remodelling, inflammation and cytotoxicity. In mice antibodies against TNF-$\alpha$ or knockout of the TNF-$\alpha$ gene confers resistance to the lethal effects of endotoxin.