Role of a serum phospholipase A1 in the phosphatidylserine-induced T cell inhibition.
We have previously shown that unsaturated phosphatidylserines inhibit mitogen-induced T cell activation. We now report that the inhibitory action requires a protein present in bovine and human serum. Partial purification and phospholipase assay show that this protein has phospholipase A activity on phosphatidylserine but not phosphatidylethanolamine, phosphatidylcholine and phosphatidylinositol. In short incubations (1-3 h)2-acyl lysophosphatidylserine is produced but in longer incubations the cis-unsaturated fatty acid is also released. Experiments on peripheral blood mononuclear cells indicate that the unsaturated fatty acid becomes the main responsible for the PS-induced inhibition and that 2-acyl lysophosphatidylserine enhances the inhibitory effect of fatty acid.
Bellini
F
F
FIDIA Research Laboratories, Abano Terme, Italy.
Bruni
A
A
D000818:Animals; D002417:Cattle; D002478:Cells, Cultured; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000276:immunology; D008213:Lymphocyte Activation / Q000502:physiology*; D010718:Phosphatidylserines / Q000502:physiology*; D010741:Phospholipases A / Q000097:blood / Q000502:physiology*; D054466:Phospholipases A1; D013601:T-Lymphocytes / Q000276:immunology*
D010718:Phosphatidylserines; D010741:Phospholipases A; D054466:Phospholipases A1