Growth of Rubella Virus in BHK 21 Cells: Electron Microscopy of Morphogenesis

The growth of rubella virus in suspended BHK 21 cells was studied by electron microscopy under conditions of one-step growth. After a latent period of 15 hr the first new virus particles were found with their number increasing successively till about 25 hr. This corresponded well with the infectivity assays obtained from these samples.

The virus is formed through two pathways; first, by budding into vesicles of the Golgi-apparatus which then are emptied outside the cells; second, to a lesser extent by budding directly from the marginal cell membrane. No accumulation of nucleoids in the cytoplasm is detected, but they are formed at the site of budding.