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Expression and cleavage of tumor necrosis factor-alpha and tumor necrosis factor receptors by human monocytic cell lines upon direct contact with stimulated T cells.
Journal article

Expression and cleavage of tumor necrosis factor-alpha and tumor necrosis factor receptors by human monocytic cell lines upon direct contact with stimulated T cells.

  • Vey E Department of Internal Medicine, Hôpital Cantonal Universitaire, Geneva, Switzerland
  • Burger D
  • Dayer JM
  • 1996-10-01
Published in:
  • European journal of immunology. - 1996
Cell Membrane
Humans
Lymphocyte Activation
Monocytes
Receptors, Tumor Necrosis Factor
Serine Endopeptidases
Signal Transduction
Solubility
T-Lymphocytes
Tumor Cells, Cultured
Tumor Necrosis Factor-alpha
English Tumor necrosis factor-alpha (TNF-alpha) is a potent cytokine in inflammatory processes. A variety of mechanisms that modulate its activity have been described, one being its binding to soluble receptors (sTNFR). In this study, we demonstrate that human monocytic cells such as THP-1 respond to direct contact with a membrane preparation of stimulated HUT-78 cells by producing TNF-alpha and by releasing sTNFR-p75, but not sTNFR-p55, with different kinetics. TNF-alpha concentration peaked after 12 h of contact and then decreased, whereas sTNFR-p75 production increased progressively upon cell/cell contact. The decrease in TNF-alpha concentration is not due to trapping of TNF-alpha by its soluble receptors or other soluble or cell-associated molecules, but rather to a proteolytic activity associated to THP-1 cells. On the other hand, the increase in sTNFR-p75 release does not result from an increase in the cleavage of pre-existing cell-associated sTNFR-p75 but from an increase in TNFR-p75 expression, immediately followed by the cleavage of its extracellular domain. Phenylmethylsulfonylfluoride, a serine protease inhibitor, has a negative effect on both TNF-alpha degradation and sTNFR-p75 release by THP-1 cells. Thus, there may be an enzymatic activity associated to THP-1 cells that plays an important role in the neutralization of TNF-alpha activity both by degrading the molecule and by cleaving its receptors at the cell surface.
Language
  • English
Open access status
closed
Identifiers
Persistent URL
https://folia.unifr.ch/global/documents/5168
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