Alpha Tocopheryl Succinate Amelioration of Retrovirus-Induced Inhibition of Macrophage Chemotaxis

The in vitro effects of vitamin E succinate on chemotactic receptor expression and early events in the signalling pathways involved in chemotaxis of peritoneal exudate cells (PEC) elicited from normal chickens and then exposed to avian erythroblastosis virus (AEV) were investigated. PEC exposed to AEV are unable to respond to the chemoattractant, complement factor C5a. AEV suppressed PEC chemotaxis is ameliorated by treatment of cells with vitamin E succinate prior to viral exposure. Treatment of PEC with vitamin E succinate and AEV, singly or in combination, does not effect the level of cell surface expression of C5a chemotactic receptors. PEC exposed to AEV exhibit elevated levels of the second messenger, diacylglycerol (DAG) and a 70% decrease in cytosolic protein kinase C (PKC) activity as compared to controls. Pretreatment of PEC with various antioxidants, including vitamin E succinate at 1.0μg/ml (1.88 μM), prior to exposure to AEV prevents the elevation of DAG levels. PEC pretreated with vitamin E exhibit normal levels of PKC following exposure to AEV, suggesting that vitamin E treatment normalizes DAG levels and prevents virus-induced depletion of PKC.