Comparative Studies on Cytopathic Effects Induced by Vesicular Stomatitis Virus in Two Cell Types

Abstract

Infection of mouse L cells with vesicular stomatitis virus (VSV) leads to an extensive cell fusion, while porcine kidney stable (PS) cells infected with VSV show only cell rounding. Therefore, comparative morphological studies on the infection of the two cell lines were carried out using a transmission or scanning electron microscope and an immunofluorescence microscope. PS cells infected with VSV contrasted to L cells infected with the same virus in the following two points; (1) the principal site of VSV maturation was the intracytoplasmic vacuolar membrane in PS cells and the plasma membrane in L cells. However, it was found that viral glycoprotein was present on the cell surface of infected PS cells; (2) the morphological changes at the cell surface of infected PS cells occurred much earlier and were severer than those at the cell surface of infected L cells. From these observations, we discuss the possibility that the surface membrane of PS cells is too sensitive to the VSV-induced cell damage to cause cell fusion.Cultures cells infected with cytocidal viruses undergo various cytopathological alterations, and those virus-induced changes termed cytopathic effects (c.p.e.) have been studied in many virus-cell system by means of morphological and biochemical analyses (1). Vesicular stomatitis virus (VSV) is one of the best known cytocidal viruses, and VSV-induced c.p.e. in several cell lines has been described (2-4, 7, 8).In monolayers of certain cell lines infected with VSV, marked polykaryocyte formation can be observed, while only cell rounding can be observed in other cell lines. In a previous report, we described that infection of porcine kidney stable (PS) cells with VSV caused only cell rounding without forming any polykaryocytes although PS cells underwent rapid cell fusion following co-cultivation with VSV-infected L cells, and it remained unclear why PS cells infected with VSV did not show any cell fusion (7).In the present communication, we describe results of a morphological comparison between mouse L cells and PS cells infected with VSV. Parallel studies were done by means of the light microscope, transmission, and scanning electron microscopes.

Investigation of the Vesicular Stomatitis Virus Matrix Protein: Uncoating and Assembly

“…A characteristic of wild-type VSV infections is the loss of a cell's normal morphology resulting in cells that become round (155,217). This ability to round the cells has been attributed to the M protein (16) and the sequential disassembly of the cytoskeleton (190).…”