Phospholipid and cholesterol composition of rubella virus and its host cell BHK 21 grown in suspension cultures.

Analysis of total lipid, phospholipid and cholesterol distribution has been conducted in parallel on BHK 21/13S cells grown in suspension cultures, on purified Rubella virus and on cells infected by the virus. Extracellular virus was purified by use of a previously described procedure (3,4). A higher content of lipid and phospholipid was found in infected cells (versus control cells) which were characterized by the presence of an unidentified nonphosphorylated lipid fraction that was detected neither in the control cells nor in the purified virus. The level and the nature of phospholipids and cholesterol of BHK 21/13S cells (infected or not) were compared to those of various clones of BHK 21cells. The same phospholipids were detected in the virus and in the cells but phosphatidyl choline level was much higher than in the control cells and lower than in the infected cells, while phosphatidyl ethanolamine content was lower than in the cells (infected or not). The presence of cardiolipin (4.4 per cent), the amount of sphingomyelin (6.9 per cent) and the molar ratio of cholesterol to phospholipids (0.26) in varions seem to favor a rubella virus maturation site in the cells.