Alteration of the Membrane Lipid Composition and Infectivity of Vesicular Stomatitis Virus

The cholesterol and phospholipid composition of the membrane of vesicular stomatitis (VS) virus was altered by growth in a sterol auxotroph Chinese hamster ovary (CHO MI) host cell and by infection of CHO MI and baby hamster kidney (BHK)-%l cells supplemented with fatty acids and dimethylethanolamine. VS virus released from infected CHO MI sterol auxotroph cells grown in delipidated serum had a 50% lower ratio of cholesterol to phospholipid and an 80% drop in infectivity measured by plaque formation on L-929 cells compared with VS virus released from infected CHO MI cells grown in fetal calf serum. When VS virus was harvested from infected BHK-21 cells fed the choline analogue dimethylethanolamine, 29% of the membrane phospholipids were phosphatidyldimethylethanolamine (PDME); 87% of the PDME was located in the external monolayer of the virus membrane as determined by phospholipase C hydrolysis. Exogenous fatty acids added to the medium of cells infected with VS virus comprised up to 30% of the fatty acyl chains of the viral glycerophospholipids. The presence of PDME or unusual fatty acyl chains in the viral membrane had no effect on viral infectivity. These data indicate that the lipid composition of the VS virus membrane is determined primarily by the lipids available in the host cell and that only cholesterol content affects the biological activity of the virus membrane.