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Quantification and characterization of high‐affinity membrane receptors for tumor necrosis factor on human leukemic cell lines
Author(s) -
Scheurich Peter,
Ücer Ugur,
Krönke Martin,
Pfizenmaier Klaus
Publication year - 1986
Publication title -
international journal of cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.475
H-Index - 234
eISSN - 1097-0215
pISSN - 0020-7136
DOI - 10.1002/ijc.2910380120
Subject(s) - receptor , tumor necrosis factor alpha , cell culture , cell surface receptor , u937 cell , biology , microbiology and biotechnology , cell , k562 cells , in vitro , biochemistry , endocrinology , genetics
The expression of specific membrane receptors for TNF‐aipha was determined on various human leukemic cell lines differing in their sensitivity to the growth‐inhibitory activity of TNF‐alpha. Binding studies with 125 Mabelled TNF‐alpha indicated specific binding in 8/10 cell lines with approximately 10‐fold differences in the quantity of TNF‐alpha bound by these distinct cell lines. Scatchard analyses of TNF‐binding revealed the existence of high‐affinity membrane receptors (Kd 1.5 × 10 −10 M ) and approximately 3,000 binding sites/cell on both U937 and K562, representing 2 cell lines with high and low TNF sensitivity, respectively. Disuccin‐imidyl‐suberate cross‐linking of receptor‐bound 125 I‐TNF‐alpha and SDS‐PAGE of membrane preparations of either U937 or K562 cells suggest a single receptor protein with an apparent molecular weight of 76 kDa. Comparison of the TNF‐alpha binding capacity versus in vitro growth inhibition provides evidence that sensitivity to TNF‐alpha is determined both at the level of receptor expression and at a post‐receptor level. IFN‐gamma strongly enhanced the TNF‐alpha‐mediated growth inhibition of 3 sensitive cell lines, but had no effect on 7 other leukemic cell lines with little or no TNF sensitivity. No correlation was found between this enhancement of TNF sensitivity and the IFN‐gamma‐mediated increase in TNF‐cell membrane receptors, suggesting that IFN‐gamma predominantly exerts its synergistic effect distal to TNF‐binding.