Ultrastructural study of virus-like particles in Chinese hamster lung cells.

Virus-like particles were found in the E36 cells. One type, associated with centrioles, consisted of two concentric shells with a diam. of 50 to 60 nm. Some of these particles were seen budding through the plasma membrane giving rise to a free immature particle showing two concentric shells and an outer envelope. Concentration of the inner shell into a nucleoid results in a mature particle characterized by a nucleoid, mainly eccentrically located, surrounded by an intermediate layer and wrapped in an envelope. The diameter of the nature and immature particles was 75 to 85 nm. The morphogenesis of this virus-like particle resembles that of the oncoviruses.