Bioassay for Tumor Necrosis Factors- and

The realization that much of the toxicity of bacterial endotoxin resulted from production of a macrophage-derived intermediate (1 ) led to the isolation and cloning of tumor necrosis factor (TNF), also known as cachectin (2 ). Since then, much evidence has accumulated to demonstrate that TNF is of prime importance in the pathogenesis of endotoxin-related tissue injury, and occupies a key proximal position in the cascade of mediators that are produced as a result of bacterial infection. These conclusions have been based in part on the accurate measurement of TNF in blood and other body fluids of humans and animals as a result of infection.