[Abortive myxovirus infection in Ehrlich's ascitic carcinoma cells. Further study of the nature of the virus-specific structures produced by heterokaryons].

Fowl plague virus-infected cells of Ehrlich ascitic carcinoma produce a noninfectious virus which is defective in fragility of its membranes. An attempt has been made to produce nondefective virus by fusion of infected Ehrlich cells with permissive cells: infected and non-infected chicken fibroblasts. The fusion of FPV-infected and 3H-uridine labeled Ehrlich ascitic carcinoma cells with infected unlabeled chicken fibroblasts using inactivated Sendai virus resulted in production of two types of labeled virus particles: with a buoyant density in cesium chloride gradient of 1.29 g/cm3 characteristic of particles produced by infected Ehrlich cells and buoyant density 1.22 g/cm3 typical of standard influenza virus. Both types of particles has infectious activity which was greater in the virus with the density of 1.22 g/cm3. However, particles with the density of 1.22 g/cm3 are not found upon the fusion of infected Ehrlich cells with uninfected chicken fibroblasts, with chicken fibroblasts early after infection, or with chicken fibroblasts treated with actinomycin D before infection. Infected chicken fibroblasts in hybrids were shown not to use the radioactive pool of Ehrlich cells and, accordingly, the virus with the density of 1.22 g/cm3 if formed from components pre-existing in Ehrlich cells. It is suggested that the standard virus buds on the areas of membranes of permissive cells which are parts of the hybrids.