Article

Polykaryocyte Formation Induced by VSV in Mouse L Cells

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Abstract

Infection of mouse L cells with VSV leads to the formation of polykaryocytes about 4 to 12 h p.i. When anti-VSV immune serum was added during the course of infection, progression of cell fusion was soon suppressed. Cycloheximide completely suppressed the cell fusion when the drug was added within 1 h p.i., while the cell fusion was not suppressed at all when the drug was added at and after 3 h. Early polykaryocyte formation, 'fusion from without', was observed only at a low level in cells infected at very high multiplicities. The development of cell fusion induced by VSV was found to be different in several cell types, although all these cells produced a rather high yield of virus: L and C-243-3 mouse cell lines showed a high level of polykaryocytosis (80 to 100%), BHK and RK-13 cells responded at low level, and PS and Vero cells showed no cell fusion in response to VSV infection. In PS cells, however, cell fusion occurred when VSV-infected L cells were co-cultivated. From these observations, the mechanism of cell fusion induced by VSV was discussed.

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... 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). ...
... Parallel studies were done by means of the light microscope, transmission, and scanning electron microscopes. ET Anti-VSV antiserum was prepared as described previously (7). ...
... It has been known that viral glycoprotein on the cell surface plays an important role in the induction of cell fusion (3,7). Thus, the observations that virus particles matured exclusively at the intracytoplasmic membrane of infected PS cells prompted us to examine whether viral glycoprotein was present on the surface of plasma mem- brane. ...
Article
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 surfaceembrane of PS cells is too sensitive to the VSV-induced cell damage to cause cell fusion.
... Vesicular stomatitis virus (VSV) grows rapidly and is highly cytopathic to several lines of mammalian cell culture (17). Recently it has been reported that marked polykaryocyte formation was observed in monolayers of some cell lines infected with VSV and that the virus replication caused cell fusion (3,10,15). These virus-cell interactions provided an excellent means for a detailed understanding of the fusion process and cytopathogenicity by using various anti-metabolites (13). ...
... Cytopathic changes occur following the development of large multi-nucleated giant cells after about 24 hr of infection. These changes are schematically represented in Fig. 7 It has also been shown that the synthesis of these proteins takes place during 2 to 3 hr p.i. (10)(11)(12). Addition of 5 to 50 ƒÊg/ml cycloheximide at 1 hr p.i. It has been shown that certain sugar analogues interfere with the multiplication of a number of enveloped RNA viruses (2,5,6) and they were equally effective in preventing the cell fusion induced by these viruses (4,9) Many studies (8,13) suggested that 2-DG and GicN interfered with the cell fusion process by altering the glycoprotein synthesis in infected cell membranes.. ...
Article
The effect of certain metabolic inhibitors on the fusion of BHK-21 cells induced by vesicular stomatitis virus (VSV) was studied. The polykaryocyte formation in infected cells and virus growth were inhibited by 2-deoxy-D-glucose and D-glucosamine. Host-cell proteins synthesis was suppressed profoundly in both BHK-21-KB and B cells infected with VSV. On the other hand, glycoprotein synthesis was significantly enhanced during the polykaryocyte formation in BHK-21-KB cells, while it was suppressed in BHK-21-B cells which were not sensitive to cell fusion by VSV.
... Wainberg and Howe have reported FFWI reaction mediated by antiviral antibody in cells infected with parainfluenza virus type 2 (17). Recent reports by Seto et al (16) and Nishiyama et al (10) have suggested, however, that FFWI is also prevented by antiviral antibody. In this report, we will present evidence which suggests that treatment of NDV-infected cells with antiviral antibody results in a considerable promotion of FFWI under certain conditions. ...
... Fusion of erythrocytes (fusion-fromwithout) at low pH has previously been reported for three togaviruses (SFV, Sindbis, and rubella) and for influenza virus (32)(33)(34). Fusion-from-within has been observed in myxovirusand rhabdovirus-infected cell cultures (35,36), and recent findings with influenza virus suggest that this may also be dependent on low pH (34) . ...
Article
Representatives of three families of enveloped viruses were shown to fuse tissue culture cells together. These were: Semliki Forest virus (SFV, a togavirus), vesicular stomatitis virus (a rhabdovirus), and two myxoviruses, fowl plaque virus and Japan influenza virus (Japan)/A/305/57). Unlike paramyxoviruses, whose fusion activity is known to occur over a broad pH range, fusion by these viruses was restricted to mildly acidic pH. The pH thresholds for the four viruses were 6.0, 6.1, 5.5, and 5.1, respectively. The precursor form of Japan influenza, which is not infectious and which contains the uncleaved hemagglutinin, had no fusion activity. This result suggested a role for the influenza hemagglutinin in the low-pH-dependent membrane fusion activity. Taken together, our results show that low-pH-induced fusion is a widespread property of enveloped animal viruses and that it may play a role in the infective process. The fusion reactions with all four viruses were fast, efficient, and easy to induce. With UV-inactivated SFV, the fusion was shown to be nonlytic and the polykaryons were viable for at least 12 h. 30 ng of SFV/1 x 10(6) BHK-21 cells were required for 50% fusion, and 250 ng sufficed to fuse the entire culture into a single polykaryon.
... Recently marked polykaryocyte formation has been observed in several cell lines infected with vesicular stomatitis virus (VSV) (I, 4,8,13). Our previous studies (14,IS) suggested that the cell fusion induced by VSV in BHK-21-KB cells was related to specific glycoprotein synthesis or carbohydrate metabolism. ...
Article
The fusion of BHK-21-KB cells by vesicular stomatitis virus was not induced in Eagle's minimal essential medium without glucose. In medium containing glucose, the rate of polykaryocyte formation decreased as the concentration of glucose was reduced below 5 mM. However, no reduction in virus production 24 hr after infection was seen under this condition. Addition of pyruvate or mannose to the culture medium caused a reversal of cell fusing activity. Cell fusion and virus growth were significantly suppressed by sodium azide and 2,4-dinitrophenol.
... DISCUSSION In this report, we have shown that highly cytolytic strains of VSV infection induced polykaryocytes when the pattern of viral protein synthesis was modified after infection. This observation is different from the VSV-induced polykarycytosis reported previously (4, 8, 10, 19, 25) in a number of ways. Nevertheless, it seems unlikely that there would be more than one mechanism of VSV-induced cell fusion. ...
Article
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