Role of extracellular virus on the maintenance of the persistent infection induced in Aedes albopictus (mosquito) cells by Sindbis virus

Abstract

Sindbis virus infection of cultured mosquito cells was found to have no effect on the growth ofthese cells; instead, a persistent infection ofthe culture followed an initial acute phase of rapid virus synthesis. Nearly all ofthe cells in the acute stage of infection were found to actively release virus in an infectious-center assay and to contain significant amounts of virus antigen as determined by immunofluorescence. Cells in the persistent phase of infection released few virions into the media, and only a small percentage of the cultured cells could be demonstrated to contain detectable amounts of virus antigen by immunofluorescence assay. In spite of the fact that nearly 100% of the cells in the persistent phase of infection were found to be virus negative by the two assays described above, the culture as a whole totally excluded the expression of superinfecting virus, as did cells in the acute phase, suggesting that most of the persistently infected cells did, indeed, contain virus information. Prevention of reinfection of the cells in the persistent phase by eliminating extracellular virus resulted in a curing of the culture such that it responded to infection by added virus much as would an uninfected culture.

Sindbis virus‐induced silencing of dengue viruses in mosquitoes

“…Infection of C6/36 cells with SIN virus is characterized by an acute phase of high levels of virus production, followed by a state of persistence that continues indefinitely (Brown & Condreay, 1986). By 6 -8 days after SIN virus infection only a small percentage of C6 / 36 cells contain detectable SIN virus-specific antigen ( Riedel & Brown, 1977). Our results confirm that subgenomic mRNAs derived from dsSIN viruses decrease rapidly after day 2 postinfection.…”

“…If this antiviral response does occur in mosquito cells, this work raises interesting questions as to how arboviruses counteract the PTGS or RNAi response. We and others have observed that transcription of dsSIN viruses is greatly reduced in C6/36 mosquito cells after 6 -8 days postinfection ( Riedel & Brown, 1977). Is this due to a PTGS or RNAi response or are other factors coming into play?…”

Superinfection exclusion of alphaviruses in three mosquito cell lines persistently infected with Sindbis virus

“…If the persistently infected mosquito cells in the experiments reported here contain sufficient protease, not only would superinfecting virus be excluded but the presence of this protease could also be responsible for the downregulation of yields of virus that occurs upon establishment of the persistently infected state. Upon primary infection of mosquito cells, vigorous viral replication occurs in all cells and large amounts of virus are shed into the medium (22). After this early phase, virus replication is downregulated and virus production falls to low levels.…”

“…After this early phase, virus replication is downregulated and virus production falls to low levels. During the persistent infection, only a fraction of the cells are actively replicating virus at any time, as shown by the fact that only a small percentage of the cells contain sufficient viral structural proteins to be detectable in an immunofluorescence assay and by the fact that upon cloning of individual cells from the persistently infected population, only a fraction of the cell clones produce virus (11,22). Thus, it appears that upon virus infection of mosquito cells, all cells initially support virus replication but that individual cells subsequently stop replicating virus.…”

Persistierende Virusinfektionen bei Tieren: Mechanismen und Konsequenzen*

“…Inzwischen wurde erganzend uber die Hemmung der b-Rezeptorubertragung an Tollwut-und Staupe-Virus-infizierten Gliomzellen berichtet. BROWN, 1977;Roux u. HOLLAND, 1979 (FRIEDMAN u. RAMSEUR, 1979). Durch einen Defekt in einem Virusprotein kann wenig oder gar kein infektioses Virus bei der nichtpermissiven Temperatur gebildet werden.…”