Purification and partial amino acid sequence of rabbit tumor necrosis factor

Good production of tumor necrosis factor (TNF) in the rabbit was obtained using Propionibacterium acnes IID 912 as a priming agent and subsequent administration of lipopolysaccharide. The physicochemical characteristics of rabbit TNF were very similar to those of murine TNF. The molecular weight of rabbit TNF was 39,000 as estimated by gel filtration, and 18,000 by SDS-PAGE. The isoelectric point was determined as pH 4.0 by isoelectric focusing. Rabbit TNF was stable within the pH range of 5.5 to 11.0, and was stable at 56 degrees C for 8 hr. It was digested by trypsin, pancreatic protease and elastase, but was resistant to neuraminidase. The amino acid sequence of rabbit TNF was determined as Ser-Ala-Ser-Arg-Ala-Leu- .... Monoclonal antibody against rabbit TNF completely inhibited both the in vivo and in vitro activity of rabbit TNF. However, this antibody could not inhibit the action of murine TNF. Antitumor activity of rabbit TNF was shown against murine and human cancer cells in vivo and in vitro, and rabbit TNF was also capable of distinguishing malignant cells from normal cells.