Detection of oncornavirus-like particles in normal and tumorigenic rat liver cell cultures.

Six epithelial cell cultures established from adult Wistar rat liver were examined by electron microscopy for oncornavirus-like particles. Two heteroploid and tumorigenic cultures demonstrated many cells with virus-like particles of type-A and type-C morphology. The remaining four, composed of diploid nontumorigenic cells, demonstrated similar virus-like particles but in few cells and only after bromodeoxyuridine treatment. The virus-like particles in the tumorigenic cultures were identified as a rat type-C virus by serological assays.