[Electron microscopic study of the usual and "minimal forms" of oncornaviruses in human embryonic lung cells cataminated with mouse cells].

Electron microscopic examinations of KLChKM (human embryo cells spontaneously contaminated with mouse cells) cell cultures revealed extracellular oncornaviruses of A and C types and intracisternal virions of A type which in their submicroscopical organization and morphogenesis were identical to oncornaviruses of mouse L cells. Also "minimal forms" (MiF) of oncornaviruses of A and C types the diameter of which was 30--70 nm were found. MiF of oncornaviruses were found to be formed in the process of budding through the cytoplasmic membrane or membranes of intracellular vacuoles.