Isolation and characterization of a tumor necrosis factor binding protein from urine

Tumor necrosis factor (TNF)/cachectin can produce both beneficial and harmful manifestations. Mechanisms may operate to counteract potentially harmful effects such as shock and cachexia. The TNF binding protein (TNF-BP), which is found at increased levels in serum and urine of patients with chronic renal failure, may play such a role. TNF-BP was purified 1,000,000-fold to homogeneity from urine of patients with chronic renal failure by use of ion exchange chromatography, affinity chromatography on TNF-Sepharose and reverse phase chromatography. The purified protein contained only one chain with an apparent Mr on sodium dodecyl sulfate-polyacrylamide gel electrophoresis of 30,000. The aminoterminal amino acid sequence D-S-V-X-P-Q-G-K-Y-I-H-P-Q-V-N-S-I-X-K-T revealed no significant homologies with previously described protein sequences. TNF-BP may act as a regulator of the bioactivities of TNF/cachectin.