title: Species specificity of human and murine tumor necrosis factor. A comparative study of tumor necrosis factor receptors.
abstract: Recombinant murine and human tumor necrosis factor (mTNF and hTNF, respectively) were radioiodinated to high specific activity using a solid-phase lactoperoxidase method. A single class of high affinity receptors for 125I-TNF was identified on TNF-sensitive murine L cells and human HeLa S2 cells. Competitive radioligand binding assays were used to study the species specificity of TNF preparations. Unlabeled hTNF competed 30-fold less effectively than mTNF for binding to L cell receptors, whereas mTNF competed to approximately the same extent as hTNF for binding to HeLa cell receptors. A similar species specificity was observed in cytotoxicity assays; hTNF was more cytotoxic for HeLa cells than mTNF. Conversely, mTNF was more growth inhibitory and cytotoxic for L cells than hTNF. mTNF. and hTNF.receptor complexes were compared by gel filtration chromatography and polyacrylamide gel electrophoresis before and after cross-linking with bis[2-(succinimidooxycarbonyloxy)ethyl]sulfone (BSOCOES). These complexes eluted in gel filtration at a position corresponding to a globular protein of 350,000 Mr. Gel autoradiographs of the fractions containing cross-linked complexes showed bands of 95,000 and 75,000 Mr as well as small amounts of higher Mr bands. mTNF and hTNF treated with BSOCOES formed cross-linked dimers and trimers. Therefore, we were unable to determine whether the 95,000 and 75,000 Mr bands represented two distinct subunits of receptors or one subunit to which either a dimer or a monomer of TNF was cross-linked. These results demonstrate species specificity in the TNF-receptor interaction. In addition, the affinity labeling studies in two species give an identical pattern for the TNF X receptor complexes, suggesting that the receptors have similar subunit composition.
mesh_terms: D000818:Animals; D001667:Binding, Competitive; D002470:Cell Survival / Q000187:drug effects; D006023:Glycoproteins / Q000378:metabolism* / Q000494:pharmacology; D006367:HeLa Cells / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D007739:L Cells / Q000187:drug effects / Q000378:metabolism; D051379:Mice; D011956:Receptors, Cell Surface / Q000302:isolation & purification / Q000378:metabolism*; D018124:Receptors, Tumor Necrosis Factor; D011994:Recombinant Proteins / Q000378:metabolism*; D013045:Species Specificity; D014409:Tumor Necrosis Factor-alpha
chemical_list: D006023:Glycoproteins; D011956:Receptors, Cell Surface; D018124:Receptors, Tumor Necrosis Factor; D011994:Recombinant Proteins; D014409:Tumor Necrosis Factor-alpha