Release of infectious bovine rhinotracheitis virus from productively infected bovine kidney cells: an electron microscopic study

An electron microscopic study of bovine kidney cells infected with infectious bovine rhinotracheitis virus revealed the development of branching membranous channels in their cytoplasms. The presence of virus particles within the lumina of these channels, both at their junctions with the perinuclear cisterna and also at various sites in the cytoplasm of the cells, suggest that such membranous structures might be concerned with the passage of virus from the perinuclear cisterna to the intercellular spaces. Morphological appearances of the membranous structures observed at various periods of infection and in various locations in the cell cytoplasm indicate they probably represent a modification of endoplasmic reticulum initiated as a consequence of virus infection of the cells. Only occasionally release of the viral particles was observed through a possible sequestration process of the folded or reduplicated nuclear envelope that enclosed the viral particles.