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Surface matrix binding alters murine peritoneal mononuclear phagocyte TNF-alpha and IL-6 induction
T Darville1, D R Tabor, S A Theus
1Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock.
Abstract:
Interferon-gamma (IFN-gamma) and bacterial lipopolysaccharide (LPS) are important promotors of mononuclear phagocyte (MO) activation. Signals derived from binding to a surface matrix also participate in promoting the activation process of MO. In this study, we examined the relative contribution of adherence in augmenting murine MO activation for cytokine production. Kinetic studies compared the production and secretion of tumor necrosis factor-alpha (TNF) and interleukin-6 (IL-6) by MO cultured as adherent monolayers to those of MO cultured as suspended cells in teflon vessels. All cells were maximally stimulated in vitro with IFN-gamma and LPS prior to analysis. Immunoprecipitation analysis of protein and RNA slot blots showed that both secreted protein and mRNA representing TNF and IL-6 are delayed two to six hours in nonadherent MO cultures compared to adherent MO cultures. Moreover, data from bioassays confirmed that these cytokines were completely functional in both systems examined. Although IFN-gamma/LPS were able to stimulate production and secretion of TNF and IL-6 in the nonadherent cells, without cell-matrix interaction, the process was significantly delayed. These data support the hypothesis that the physical event of adherence significantly facilitates the production of specific cytokines by activated MO.
Insights
Cell adherence significantly speeds up the production of tumor necrosis factor-alpha (TNF) and interleukin-6 (IL-6) by activated mononuclear phagocytes (MO). This interaction facilitates faster cytokine release compared to suspended cells.
Area of Science:
- Immunology
- Cell Biology
- Molecular Biology
Background:
- Mononuclear phagocytes (MO) are crucial immune cells activated by signals like interferon-gamma (IFN-gamma) and bacterial lipopolysaccharide (LPS).
- Cellular adherence to a surface matrix is also known to influence MO activation and function.
Purpose of the Study:
- To investigate the role of cell adherence in enhancing murine MO activation for cytokine production.
- To compare the kinetics of cytokine production in adherent versus non-adherent MO cultures.
Main Methods:
- Kinetic studies comparing adherent MO monolayers and suspended MO in teflon vessels.
- Stimulation of MO with IFN-gamma and LPS in vitro.
- Analysis of tumor necrosis factor-alpha (TNF) and interleukin-6 (IL-6) production using immunoprecipitation, RNA slot blots, and bioassays.
Main Results:
- Adherent MO cultures exhibited a 2–6 hour earlier production and secretion of TNF and IL-6 compared to non-adherent cultures.
- Both secreted proteins and mRNA for TNF and IL-6 were delayed in non-adherent MO.
- The produced cytokines were confirmed to be functional in both adherent and non-adherent systems.
Conclusions:
- Cell adherence significantly facilitates the production and secretion of specific cytokines by activated MO.
- While IFN-gamma/LPS can stimulate cytokine production in non-adherent MO, cell-matrix interaction is essential for timely release.
- Physical adherence plays a critical role in augmenting the inflammatory response mediated by mononuclear phagocytes.