Lipid Saturation in the Target Cells Plasma Membrane Blocks Tumor Necrosis Factor Mediated Cell Killing
Destruction of sensitive tumor cells by tumor necrosis factor (TNF) is greatly influenced by the composition and the physical state of the lipids within the plasma membrane of the target cells. Experimental conditions that reduce the fluidity of the lipid bilayer of the membrane decrease or completely abolish TNF sensitivity of the target cells. One possible explanation for this phenomenon is the restricted availability of ceramide and arachidonic acid containing phospholipids to enzymes mediating the effects of TNF or decreased activity of the enzymes towards these phospholipids in membranes of decreased fluidity. Since microviscosity and lipid composition of the plasma membrane is known to be altered by the diet and by mediators derived from the neuro-endocrine and the immune systems, the physiological significance of these findings is clear. This phenomenon might also serve as a basis for better treatments for malignant diseases.
KeywordsTumor Necrosis Factor L929 Cell Spin Label Catalytic Hydrogenation Spin Probe
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