Tumour-necrosis factor from the rabbit. IV. Purification and chemical characterization

Abstract

Serum from rabbits with BCG/endotoxin-induced shock is growth inhibitory or cytotoxic to a range of tumour cell lines. The active component, tumour-necrosis factor (TNF), has been purified 1000-fold by sequential salt precipitation, ion-exchange chromatography and gel-filtration. TNF had a mol. wt of 67, 000 on gradient PAGE and 39, 000 on Ultrogel AcA44 gelfiltration. The isoelectric point was pH 5-1-5-2. TNF was susceptible to the proteolytic enzyme pronase, but resistant to trypsin or papain. On isopycnic ultracentrifugation it had a buoyant density of 127, confirming that it is protein in nature, with little or no carbohydrate. This is also suggested by its failure to bind to a range of lectins. © 1980 Cancer Research Campaign. All rights reserved.