title: Characterization of specific high affinity receptors for human tumor necrosis factor on mouse fibroblasts.
abstract: Mouse L-929 fibroblasts, an established line of cells, are very sensitive to lysis by human lymphotoxin (hTNF-beta). Specific binding of a highly purified preparation of hTNF-beta to these cells was examined. Recombinant DNA-derived hTNF-beta was radiolabeled with [3H]propionyl succinimidate at the lysine residues of the molecule to a specific activity of 200 microCi/nmol of protein. [3H]hTNF-beta was purified by high performance gel permeation chromatography and the major fraction was found to be monomeric by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The labeled hTNF-beta was fully active in causing lysis of L-929 fibroblasts and bound specifically to high affinity binding sites on these cells. Scatchard analysis of the binding data revealed the presence of a single class of high affinity receptors with an apparent Kd of 6.7 X 10(-11) M and a capacity of 3200 binding sites/cell. Unlabeled recombinant DNA-derived hTNF-beta was found to be approximately 5-fold more effective competitive inhibitor of binding than the natural hTNF-beta. The binding of hTNF-beta to these mouse fibroblasts was also correlated with the ultimate cell lysis. Neutralizing polyclonal antibodies to hTNF-beta efficiently inhibited the binding of [3H]hTNF-beta to the cells. We conclude that the specific high affinity binding site is the receptor for hTNF-beta and may be involved in lysis of cells.
mesh_terms: D000818:Animals; D000936:Antigen-Antibody Complex; D001667:Binding, Competitive; D006023:Glycoproteins / Q000378:metabolism*; D006131:Growth Inhibitors / Q000378:metabolism*; D006801:Humans; D007106:Immune Sera; D007700:Kinetics; D007739:L Cells / Q000378:metabolism; D051379:Mice; D011956:Receptors, Cell Surface / Q000378:metabolism*; D018124:Receptors, Tumor Necrosis Factor; D011994:Recombinant Proteins / Q000378:metabolism*; D014316:Tritium; D014409:Tumor Necrosis Factor-alpha
chemical_list: D000936:Antigen-Antibody Complex; D006023:Glycoproteins; D006131:Growth Inhibitors; D007106:Immune Sera; D011956:Receptors, Cell Surface; D018124:Receptors, Tumor Necrosis Factor; D011994:Recombinant Proteins; D014409:Tumor Necrosis Factor-alpha; D014316:Tritium