Interferon enhances phospholipase A2 activity in bovine aortic endothelial cells

The effect of human interferon-alpha (IFN) on the activity of PLA2 in bovine aortic endothelial cells (BAEC) was studied. A novel method for determination of PLA2 activity in intact cell membranes with a fluorescent analogue of phosphatidylcholine, was employed. It was found that pretreatment of BAEC with human leukocyte IFN alpha or recombinant human IFN alpha 2 enhanced PLA2 activity as a function of IFN concentration. Since PLA2 activity is responsive to the lipid composition of its environment, we analyzed the fatty acyl chain composition of the cell lipids after treatment with IFN. It was found that both IFN alpha and IFN alpha 2 markedly increased the content of arachidonic acid. We suggest that exposure of BAEC to IFN enhances the activity of the cell membrane PLA2 concomitantly with enrichment of the cell membrane lipids with arachidonic acid.