scholarly journals Interaction of Yellow Fever Virus French Neurotropic Vaccine Strain with Monkey Brain: Characterization of Monkey Brain Membrane Receptor Escape Variants

2000 ◽  
Vol 74 (6) ◽  
pp. 2903-2906 ◽  
Author(s):  
Haolin Ni ◽  
Kate D. Ryman ◽  
Heiman Wang ◽  
Mohammad F. Saeed ◽  
Robin Hull ◽  
...  

ABSTRACT Binding of yellow fever virus wild-type strains Asibi and French viscerotropic virus and vaccine strains 17D and FNV to monkey brain and monkey liver cell membrane receptor preparations (MRPs) was investigated. Only FNV bound to monkey brain MRPs, while French viscerotropic virus, Asibi, and FNV all bound to monkey liver MRPs. Four monkey brain and two mouse brain MRP escape (MRPR) variants of FNV were selected at pH 7.6 and 6.0. Three monkey brain MRPR variants selected at pH 7.6 each had only one amino acid substitution in the envelope (E) protein in domain II (E-237, E-260, or E274) and were significantly attenuated in mice following intracerebral inoculation. Two of the variants were tested in monkeys and retained parental neurotropism following intracerebral inoculation at the dose tested. We speculate that this region of domain II is involved in binding of FNV E protein to monkey brain and is, in part, responsible for the enhanced neurotropism of FNV for monkeys. A monkey brain MRPR variant selected at pH 6.0 and two mouse brain MRPR variants selected at pH 7.6 were less attenuated in mice, and each had an amino acid substitution in the transmembrane region of the E protein (E-457 or E-458).

2001 ◽  
Vol 75 (2) ◽  
pp. 934-942 ◽  
Author(s):  
Juan Arroyo ◽  
Farshad Guirakhoo ◽  
Sabine Fenner ◽  
Zhen-Xi Zhang ◽  
Thomas P. Monath ◽  
...  

ABSTRACT A yellow fever virus (YFV)/Japanese encephalitis virus (JEV) chimera in which the structural proteins prM and E of YFV 17D are replaced with those of the JEV SA14-14-2 vaccine strain is under evaluation as a candidate vaccine against Japanese encephalitis. The chimera (YFV/JEV SA14-14-2, or ChimeriVax-JE) is less neurovirulent than is YFV 17D vaccine in mouse and nonhuman primate models (F. Guirakhoo et al., Virology 257:363–372, 1999; T. P. Monath et al., Vaccine 17:1869–1882, 1999). Attenuation depends on the presence of the JEV SA14-14-2 E protein, as shown by the high neurovirulence of an analogous YFV/JEV Nakayama chimera derived from the wild JEV Nakayama strain (T. J. Chambers, A. Nestorowicz, P. W. Mason, and C. M. Rice, J. Virol. 73:3095–3101, 1999). Ten amino acid differences exist between the E proteins of ChimeriVax-JE and the YFV/JEV Nakayama virus, four of which are predicted to be neurovirulence determinants based on various sequence comparisons. To identify residues that are involved in attenuation, a series of intratypic YFV/JEV chimeras containing either single or multiple amino acid substitutions were engineered and tested for mouse neurovirulence. Reversions in at least three distinct clusters were required to restore the neurovirulence typical of the YFV/JEV Nakayama virus. Different combinations of cluster-specific reversions could confer neurovirulence; however, residue 138 of the E protein (E138) exhibited a dominant effect. No single amino acid reversion produced a phenotype significantly different from that of the ChimeriVax-JE parent. Together with the known genetic stability of the virus during prolonged cell culture and mouse brain passage, these findings support the candidacy of this experimental vaccine as a novel live-attenuated viral vaccine against Japanese encephalitis.


2003 ◽  
Vol 77 (6) ◽  
pp. 3655-3668 ◽  
Author(s):  
Thomas J. Chambers ◽  
Yan Liang ◽  
Deborah A. Droll ◽  
Jacob J. Schlesinger ◽  
Andrew D. Davidson ◽  
...  

ABSTRACT Two yellow fever virus (YFV)/dengue virus chimeras which encode the prM and E proteins of either dengue virus serotype 2 (dengue-2 virus) or dengue-4 virus within the genome of the YFV 17D strain (YF5.2iv infectious clone) were constructed and characterized for their properties in cell culture and as experimental vaccines in mice. The prM and E proteins appeared to be properly processed and glycosylated, and in plaque reduction neutralization tests and other assays of antigenic specificity, the E proteins exhibited profiles which resembled those of the homologous dengue virus serotypes. Both chimeric viruses replicated in cell lines of vertebrate and mosquito origin to levels comparable to those of homologous dengue viruses but less efficiently than the YF5.2iv parent. YFV/dengue-4 virus, but not YFV/dengue-2 virus, was neurovirulent for 3-week-old mice by intracerebral inoculation; however, both viruses were attenuated when administered by the intraperitoneal route in mice of that age. Single-dose inoculation of either chimeric virus at a dose of 105 PFU by the intraperitoneal route induced detectable levels of neutralizing antibodies against the homologous dengue virus strains. Mice which had been immunized in this manner were fully protected from challenge with homologous neurovirulent dengue viruses by intracerebral inoculation compared to unimmunized mice. Protection was associated with significant increases in geometric mean titers of neutralizing antibody compared to those for unimmunized mice. These data indicate that YFV/dengue virus chimeras elicit antibodies which represent protective memory responses in the mouse model of dengue encephalitis. The levels of neurovirulence and immunogenicity of the chimeric viruses in mice correlate with the degree of adaptation of the dengue virus strain to mice. This study supports ongoing investigations concerning the use of this technology for development of a live attenuated viral vaccine against dengue viruses.


2006 ◽  
Vol 87 (4) ◽  
pp. 895-907 ◽  
Author(s):  
Jana J. von Lindern ◽  
Sarah Aroner ◽  
Nicholas D. Barrett ◽  
Jason A. Wicker ◽  
C. Todd Davis ◽  
...  

Yellow fever virus (YFV), a reemerging disease agent in Africa and South America, is the prototype member of the genus Flavivirus. Based on examination of the prM/M, E and 3′ non-coding regions of the YFV genome, previous studies have identified seven genotypes of YFV, including the Angolan, east/central African and east African genotypes, which are highly divergent from the prototype strain Asibi. In this study, full genome analysis was used to expand upon these genetic relationships as well as on the very limited full genome database for YFV. This study was the first to investigate genomic sequences of YFV strains from east and central Africa (Angola71, Uganda48a and Ethiopia61b). All three viruses had genomes of 10 823 nt in length. Compared with the prototype strain Asibi (from west Africa) they were approximately 25 % divergent in nucleotide sequence and 7 % divergent in amino acid sequence. Comparison of multiple flaviviruses in the N-terminal region of NS4B showed that amino acid sequences were variable and that west African strains of YFV had an amino acid deletion at residue 21. Additionally, N-linked glycosylation sites were conserved between viral genotypes, while codon usage varied between strains.


2004 ◽  
Vol 78 (18) ◽  
pp. 9998-10008 ◽  
Author(s):  
F. Guirakhoo ◽  
Z. Zhang ◽  
G. Myers ◽  
B. W. Johnson ◽  
K. Pugachev ◽  
...  

ABSTRACT A chimeric yellow fever-dengue 1 (ChimeriVax-DEN1) virus was produced by the transfection of Vero cells with chimeric in vitro RNA transcripts. The cell culture supernatant was subjected to plaque purification for the identification of a vaccine candidate without mutations. Of 10 plaque-purified clones, 1 containing no mutation (clone J) was selected for production of the vaccine virus. During subsequent cell culture passaging of this clone for vaccine production, a single amino acid substitution (K to R) occurred in the envelope (E) protein at residue 204 (E204) (F. Guirakhoo, K. Pugachev, Z. Zhang, G. Myers, I. Levenbook, K. Draper, J. Lang, S. Ocran, F. Mitchell, M. Parsons, N. Brown, S. Brandler, C. Fournier, B. Barrere, F. Rizvi, A. Travassos, R. Nichols, D. Trent, and T. Monath, J. Virol. 78:4761-4775, 2004). The same mutation was observed in another clone (clone E). This mutation attenuated the virus in 4-day-old suckling mice inoculated by the intracerebral (i.c.) route and led to reduced viremia in monkeys inoculated by the subcutaneous or i.c. route. The histopathology scores of lesions in the brain tissue of monkeys inoculated with either the E204K or E204R virus were reduced compared to those for monkeys inoculated with the reference virus, a commercial yellow fever 17D vaccine (YF-VAX). Both viruses grew to significantly lower titers than YF-VAX in HepG2, a human hepatoma cell line. After intrathoracic inoculation into mosquitoes, both viruses grew to a similar level as YF-VAX, which was significantly lower than that of their wild-type DEN1 parent virus. A comparison of the E-protein structures of nonmutant and mutant viruses suggested the appearance of new intramolecular bonds between residues 204R, 261H, and 257E in the mutant virus. These changes may be responsible for virus attenuation through a change in the pH threshold for virus envelope fusion with the host cell membrane.


Virology ◽  
1987 ◽  
Vol 161 (2) ◽  
pp. 474-478 ◽  
Author(s):  
M. Lobigs ◽  
L. Dalgarno ◽  
J.J. Schlesinger ◽  
R.C. Weir

2007 ◽  
Vol 81 (21) ◽  
pp. 11737-11748 ◽  
Author(s):  
Alexandr V. Shustov ◽  
Peter W. Mason ◽  
Ilya Frolov

ABSTRACT Application of genetically modified, deficient-in-replication flaviviruses that are incapable of developing productive, spreading infection is a promising means of designing safe and effective vaccines. Here we describe a two-component genome yellow fever virus (YFV) replication system in which each of the genomes encodes complete sets of nonstructural proteins that form the replication complex but expresses either only capsid or prM/E instead of the entire structural polyprotein. Upon delivery to the same cell, these genomes produce together all of the viral structural proteins, and cells release a combination of virions with both types of genomes packaged into separate particles. In tissue culture, this modified YFV can be further passaged at an escalating scale by using a high multiplicity of infection (MOI). However, at a low MOI, only one of the genomes is delivered into the cells, and infection cannot spread. The replicating prM/E-encoding genome produces extracellular E protein in the form of secreted subviral particles that are known to be an effective immunogen. The presented strategy of developing viruses defective in replication might be applied to other flaviviruses, and these two-component genome viruses can be useful for diagnostic or vaccine applications, including the delivery and expression of heterologous genes. In addition, the achieved separation of the capsid-coding sequence and the cyclization signal in the YFV genome provides a new means for studying the mechanism of the flavivirus packaging process.


mBio ◽  
2016 ◽  
Vol 7 (1) ◽  
Author(s):  
Maria Dolores Fernandez-Garcia ◽  
Laurent Meertens ◽  
Maxime Chazal ◽  
Mohamed Lamine Hafirassou ◽  
Ophélie Dejarnac ◽  
...  

ABSTRACTThe live attenuated yellow fever virus (YFV) vaccine 17D stands as a “gold standard” for a successful vaccine. 17D was developed empirically by passaging the wild-type Asibi strain in mouse and chicken embryo tissues. Despite its immense success, the molecular determinants for virulence attenuation and immunogenicity of the 17D vaccine are poorly understood. 17D evolved several mutations in its genome, most of which lie within the envelope (E) protein. Given the major role played by the YFV E protein during virus entry, it has been hypothesized that the residues that diverge between the Asibi and 17D E proteins may be key determinants of attenuation. In this study, we define the process of YFV entry into target cells and investigate its implication in the activation of the antiviral cytokine response. We found that Asibi infects host cells exclusively via the classical clathrin-mediated endocytosis, while 17D exploits a clathrin-independent pathway for infectious entry. We demonstrate that the mutations in the 17D E protein acquired during the attenuation process are sufficient to explain the differential entry of Asibi versus 17D. Interestingly, we show that 17D binds to and infects host cells more efficiently than Asibi, which culminates in increased delivery of viral RNA into the cytosol and robust activation of the cytokine-mediated antiviral response. Overall, our study reveals that 17D vaccine and Asibi enter target cells through distinct mechanisms and highlights a link between 17D attenuation, virus entry, and immune activation.IMPORTANCEThe yellow fever virus (YFV) vaccine 17D is one of the safest and most effective live virus vaccines ever developed. The molecular determinants for virulence attenuation and immunogenicity of 17D are poorly understood. 17D was generated by serially passaging the virulent Asibi strain in vertebrate tissues. Here we examined the entry mechanisms engaged by YFV Asibi and the 17D vaccine. We found the two viruses use different entry pathways. We show that the mutations differentiating the Asibi envelope (E) protein from the 17D E protein, which arose during attenuation, are key determinants for the use of these distinct entry routes. Finally, we demonstrate that 17D binds and enters host cells more efficiently than Asibi. This results in a higher uptake of viral RNA into the cytoplasm and consequently a greater cytokine-mediated antiviral response. Overall, our data provide new insights into the biology of YFV infection and the mechanisms of viral attenuation.


2008 ◽  
Vol 82 (12) ◽  
pp. 6024-6033 ◽  
Author(s):  
Eva Lee ◽  
Mario Lobigs

ABSTRACT The yellow fever virus (YFV) 17D strain is one of the most effective live vaccines for human use, but the in vivo mechanisms for virulence attenuation of the vaccine and the corresponding molecular determinants remain elusive. The vaccine differs phenotypically from wild-type YFV by the loss of viscerotropism, despite replicative fitness in cell culture, and genetically by 20 amino acid changes predominantly located in the envelope (E) protein. We show that three residues in E protein domain III inhibit spread of 17D in extraneural tissues and attenuate virulence in type I/II interferon-deficient mice. One of these residues (Arg380) is a dominant glycosaminoglycan-binding determinant, which mainly accounts for more rapid in vivo clearance of 17D from the bloodstream in comparison to 17D-derived variants with wild-type-like E protein. While other mutations will account for loss of neurotropism and phenotypic stability, the described impact of E protein domain III changes on virus dissemination and virulence is the first rational explanation for the safety of the 17D vaccine in humans.


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