Low pH-induced Cell Fusion in Flavivirus-infected Aedes Albopictus Cell Cultures

Randolph, Valerie B.; Stollar, Victor

doi:10.1099/0022-1317-71-8-1845

Cited by 89 publications

(85 citation statements)

References 27 publications

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“…Consistent with a penetration mechanism involving acidic vesicles, it was shown that weak bases can inhibit flavivirus replication in certain cells (Brandriss & Schlesinger, 1984;Gollins & Porterfield, 1984;Randolph & Stollar, 1990) and cause an accumulation of virus particles in endosomes (Collins & Porterfield, 1985). The pH-dependent fusion activity of certain flaviviruses was demonstrated with model membranes , by fusion from without (FFWO) (Summers et al, 1989) and by fusion from within (Randolph & Stollar, 1990).…”

Section: Introductionmentioning

confidence: 89%

“…The proteolytic cleavage of prM as a last step in virus maturation seems to be necessary to yield fully infectious virus (Wengler & Wengler, 1989). Recent data obtained with dengue, JE and Powassan viruses provide evidence that the processing of prM takes place in acidic vesicles of the post-Golgi network, as it can be inhibited by acidotropic amines (Randolph et al, 1990). We used ammonium chloride to generate and isolate prMcontaining TBE virus from the supernatant of infected chick embryo cells.…”

Section: Discussionmentioning

confidence: 99%

“…Recently it has been shown that the proteolytic processing o f p r M to yield M probably takes place in acidic postGolgi vesicles (Randolph et al, 1990) and can be blocked by the addition of acidotropic agents. To generate prMcontaining virions we infected chick embryo cells and harvested the virus from the supernatant after addition of ammonium chloride late in the infection cycle (see Methods).…”

Section: Analysis Of Immature Virions Containing Prmmentioning

confidence: 99%

“…Cross-linking experiments indicate that the cleavage of prM may be associated with a rearrangement of the oligomeric structures on the surface of the virus (Wengler 0001-0016 © 1991 SGM F. Guirakhoo and others & Wengler, 1989). Recent data provide evidence that this proteolytic maturation event takes place in acidic post-Golgi vesicles and can be inhibited by acidotropic amines such as chloroquine, ammonium chloride or methylamine (Randolph & Stollar, 1990).…”

Section: Introductionmentioning

confidence: 99%

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Fusion activity of flaviviruses: comparison of mature and immature (prM-containing) tick-borne encephalitis virions

Guirakhoo

Heinz²,

Mandl³

et al. 1991

Journal of General Virology

170

156

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The fusion activity of flaviviruses [tick-borne encephalitis (TBE) virus and Japanese encephalitis virus] was assessed by inducing fusion from without of C6/36 mosquito cells with purified virus preparations. Membrane fusion and polykaryocyte formation was observed only after incubating the viruses at acidic pH. Two groups of monoclonal antibodies reacting with distinct non-overlapping antigenic domains on the TBE virus protein E inhibited fusion from without. One of these domains contains the most highly conserved and putative fusion-active sequence of the flavivirus protein E. Of five TBE virus monoclonal antibody escape mutants, each defined by a single amino acid substitution in the envelope protein E, one revealed a reduced fusion activity and another one a lower pH threshold. TBE virus grown in the presence of ammonium chloride as well as Langat virus purified from the supernatant of infected chick embryo cells contained the precursor of protein M (prM) rather than M itself. These 'immature' virions did not cause fusion from without, suggesting that the proteolytic processing of prM may be necessary for the generation of fusion-competent virions.

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Section: Introductionmentioning

confidence: 89%

Section: Discussionmentioning

confidence: 99%

Section: Analysis Of Immature Virions Containing Prmmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Fusion activity of flaviviruses: comparison of mature and immature (prM-containing) tick-borne encephalitis virions

Guirakhoo

Heinz²,

Mandl³

et al. 1991

Journal of General Virology

170

156

View full text Add to dashboard Cite

show abstract

“…There have, however, been a number of reports suggesting that certain flaviviruses can cause fusion of mosquito cells. The precise requirements for fusion appear to be a function of the mosquito cell line used and other culture parameters (Igarashi, 1978(Igarashi, , 1979Ng & Westaway, 1980;Randolph & Stollar, 1990). For SLE virus, persistent infection has been detected in several arthropod cell lines (Randolph & Hardy, 1988a;Oro, 1984;Leake et al, 1980).…”

Section: St Louis Encephalitis (Sle) Virus a Member Of The Familymentioning

confidence: 99%

St Louis encephalitis virus establishes a productive, cytopathic and persistent infection of Sf9 cells

Zhang

Klutch²,

Müller³

et al. 1993

Journal of General Virology

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The Sf9 cell line, commonly used for gene expression by recombinant baculovirus, has been productively infected by St Louis encephalitis (SLE) virus, a flavivirus. SLE viral infection produced a c.p.e, in the SO cells characterized by giant cells and the presence of 10-fold fewer cells in the infected cultures after the first week of infection compared with uninoculated control cultures. Infected Sf9 cells expressed SLE viral antigens, and intracellular virus particles were observed by electron microscopy. Titres of cell-associated SLE virus rose slightly over an 8 week period, whereas titres of cell-free virus remained stable, suggesting that SLE virus establishes a productive and persistent infection of Sf9 cells. The SLE virus produced by the Sf9 cells could be neutralized by SLE virus-immune mouse ascitic fluid, and no evidence of escape mutants was detected. Sf9 cells persistently infected with SLE virus could be superinfected with a recombinant baculovirus and expressed recombinant antigen. The successful infection of SD cells by SLE virus represents the first report of production of c.p.e, by SLE virus in insect cells under routine cell culture conditions and of the infection of Sf9 cells by a human pathogen.

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Changes in the Dengue Virus Major Envelope Protein on Passaging and Their Localization on the Three-Dimensional Structure of the Protein

1997

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To help define the molecular events involved in dengue virus adaptation during serial passage in vivo and in cultured cells, we have sequenced the structural protein genes of three dengue type 3 isolates after intracerebral passage in mice and after passage in cultured monkey kidney (Vero) and Aedes albopictus (mosquito) cells. Passaging in each host selected for amino acid changes in the envelope protein E and occasionally in prM but not in the capsid protein. Most changes were first apparent within five passages. Nineteen of twenty mutations in the structural protein genes resulted in amino acid changes concentrated on 12 residues; 9 of the 12 amino acid changes were at residues which are conserved between the four dengue virus serotypes. Certain amino acid changes were repeatedly selected on passage in cell culture. In six independent Vero cell passage series, changes were observed in E at residues 191 (four times), 202 (twice), 266 and 268 (three times), and 291; change in prM was seen in two passage series at residue 26. Two independent passage series in mosquito cells each resulted in the loss of a conserved glycosylation site at Asn 153 in E. Passage in mouse brain selected for mutations at E residues 18, 54, 277, 401, and 403. Residues which altered on passaging have been localized on the three-dimensional structure of the tick-borne encephalitis virus E protein soluble fragment (F. A. Rey, et al., 1995, Nature 375, 291-298). Residues 54, 191, 202, 266, 268, and 277 map to a postulated "hinge" region between domains I and II which may be involved in fusion of flaviviruses with cell membranes. The oligosaccharide at Asn 153 also appears to be involved in flavivirus fusion. Changes in the fusion characteristics of the passaged viruses were demonstrated.

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Low pH-induced Cell Fusion in Flavivirus-infected Aedes Albopictus Cell Cultures

Cited by 89 publications

References 27 publications

Fusion activity of flaviviruses: comparison of mature and immature (prM-containing) tick-borne encephalitis virions

Fusion activity of flaviviruses: comparison of mature and immature (prM-containing) tick-borne encephalitis virions

St Louis encephalitis virus establishes a productive, cytopathic and persistent infection of Sf9 cells

Changes in the Dengue Virus Major Envelope Protein on Passaging and Their Localization on the Three-Dimensional Structure of the Protein

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