Plasma membrane lipids and parainfluenza virus assembly

Abstract

The lipids of bovine kidney (MDBK) and hamster kidney (HaK) cells, their plasma membranes, and parainfluenza (SV5) virions grown in these cells have been analyzed and compared with previous results with rhesus monkey kidney (MK) and baby hamster kidney (BHK21-F) cells. Features common to all plasma membranes include a high content of cholesterol, sphingomyelin, and saturated fatty acids. The fatty acid composition of cells and plasma membranes depends to a large extent on the fatty acids in the medium. However, each of the membranes has a distinct and specific phospholipid pattern and molar ratio of cholesterol to phospholipid. With few exceptions, the lipids of virions closely resemble those of the plasma membrane of the cell in which the virus was grown. The results indicate that, in general, the virions acquire the lipid pattern of the plasma membrane of the host cell. However, a lipid pattern characterized by a high phosphatidylethanolamine and relatively lower phosphatidylcholine content may be optimal for the formation of SV5 virions. These conditions are met in the MK membrane, and this cell produces a very high yield of SV5 virions. MDBK membranes have a slightly different lipid pattern, but do contain much phosphatidylethanolamine, and MDBK cells produce a moderately high yield of virus with a lipid composition similar to that of virus grown in MK cells. This suggests that, within narrow limits, some selective rearrangement of membrane lipids incorporated into virions is possible in some cells. Hamster cell membranes have a very different set of lipids, which are incorporated essentially unchanged into virions, and these cells produce a very low yield of virus. The data suggest a correlation between membrane lipid composition and virus yield, and possibly other biological properties of the plasma membranes.