Recombinant TNF is a bioactive protein intended for use in cell culture applications. TNF causes cytolysis and cytostasis of many tumor cell lines. TNF has a wide spectrum of activities, including chemotaxis of neutrophils, alteration of the endothelium, inhibition of anticoagulatory mechanisms, and promotion of angiogenesis. ED50 range = 0.02 to 0.05 ng⁄mL (Specific Activity: 2 x 10^7 to 5 x 10^7 units⁄mg), determined by the dose dependent cytotoxic effect on L929 cells in the presence of actinomycin D.