Ultrastructure of mouse periventricular and choroid plexus tissues in experimental vesicular stomatitis virus infection.

The ultrastructure of the periventricular and choroid plexus tissues was studied in the three-week-old mouse, infected with the vesicular stomatitis virus (VSV) by the intranasal route. The VSV reached the periventricular ependymal lining late in infection. It was carried within the cytoplasm of myelinated axons and their sheath cells. Inflammatory cells, although few in numbers, may have also contributed to the virus dissemination. Once in the periventricular tissues the VSV entered the cells from the intercellular space. It replicated in both the ependymal and subependymal cells. It matured either directly in the cytoplasm, or by budding from the plasmalemma as well as the cytoplasmic membranes. In numerous cells the cytoplasmic membranes formed the so-called undulating tubules which contained the VSV particles. The infected ependymal cells became necrotic and separated from the ventricular surface. The changes were similar in all three of the cerebral ventricles. At no time during the infection was the VSV observed near or within any of the choroid plexuses. Some ultrastructural changes, however, occurred in the choroidal epithelial cells. These may have developed either as a consequence of viral damage in the periventricular tissues, or due to virus presence in the cerebral ventricles.