Characterization and complete genome sequences of high- and low-virulence variants of tick-borne encephalitis virus

Wallner, Gerhard; Mandl, Christian W.; Ecker, Michael; Holzmann, Heidemarie; Stiasny, Karin; Künz, Christian; Heinz, Franz X.

doi:10.1099/0022-1317-77-5-1035

Cited by 79 publications

(50 citation statements)

References 42 publications

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“…Protection of mice was tested by an i.p. challenge-inoculation with a highly lethal dose (Ͼ1,000 LD 50 ) of the virulent TBEV strain Hypr (23).…”

Section: Methodsmentioning

confidence: 99%

“…The feasibility of using noninfectious, replicating RNA for immunization was assessed in the established adult mouse model (9,23,25). Groups of four mice were inoculated by gene-gun bombardment with gold particles coated with in vitro-transcribed RNAs from mutant C(⌬28 -89), C(⌬28 -89)-S, ⌬NS5 (replication-deficient control), or untreated gold particles (mock control).…”

Section: Figmentioning

confidence: 99%

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Mimicking live flavivirus immunization with a noninfectious RNA vaccine

Kofler

Aberle

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

108

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Flaviviruses are human pathogens of world-wide medical importance. They have recently received much additional attention because of their spread to new regions (such as West Nile virus to North America), highlighting their potential as newly emerging disease agents. Using tick-borne encephalitis virus, we have developed and evaluated in mice a new genetic vaccine based on self-replicating but noninfectious RNA. This RNA contains all of the necessary genetic information for establishing its replication machinery in the host cell, thus mimicking a natural infection. However, genetic modifications in the region encoding the capsid protein simultaneously prevent the assembly of infectious virus particles and promote the secretion of noninfectious subviral particles that elicit neutralizing antibodies. These characteristics demonstrate that a new generation of flavivirus vaccines can be designed that stimulate the same spectrum of innate and specific immune responses as a live vaccine but have the safety features of an inactivated vaccine.

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“…Protection of mice was tested by an i.p. challenge-inoculation with a highly lethal dose (Ͼ1,000 LD 50 ) of the virulent TBEV strain Hypr (23).…”

Section: Methodsmentioning

confidence: 99%

Section: Figmentioning

confidence: 99%

Mimicking live flavivirus immunization with a noninfectious RNA vaccine

Kofler

Aberle

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

108

View full text Add to dashboard Cite

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“…Then the mice were bled, and seroconversion was detected by a TBE antibody ELISA (13). For the determination of the 50% lethal dose (LD 50 ) and the 50% infective dose (ID 50 ), groups of 10 mice were inoculated with sequential 10-fold dilutions of virus ranging from 1 to 10 6 PFU. The calculation of LD 50 and ID 50 values was performed by the method of Reed and Muench (41).…”

Section: Vol 76 2002 Deletions In Flavivirus Capsid Protein C 3535mentioning

confidence: 99%

“…The calculation of LD 50 and ID 50 values was performed by the method of Reed and Muench (41). For ID 50 calculations, the number of infected mice was taken to be the total of mice killed plus surviving mice with detectable seroconversion. Surviving mice without detectable serum antibody were scored as uninfected.…”

Section: Vol 76 2002 Deletions In Flavivirus Capsid Protein C 3535mentioning

confidence: 99%

“…For the determination of the 50% lethal dose (LD 50 ) and the 50% infective dose (ID 50 ), groups of 10 mice were inoculated with sequential 10-fold dilutions of virus ranging from 1 to 10 6 PFU. The calculation of LD 50 and ID 50 values was performed by the method of Reed and Muench (41). For ID 50 calculations, the number of infected mice was taken to be the total of mice killed plus surviving mice with detectable seroconversion.…”

Section: Vol 76 2002 Deletions In Flavivirus Capsid Protein C 3535mentioning

confidence: 99%

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Capsid Protein C of Tick-Borne Encephalitis Virus Tolerates Large Internal Deletions and Is a Favorable Target for Attenuation of Virulence

Kofler

Heinz

Mandl

2002

J Virol

119

129

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Deletions ranging in size from 4 to 21 amino acid residues were introduced into the capsid protein of the flavivirus tick-borne encephalitis (TBE) virus. These deletions incrementally affected a hydrophobic domain which is present at the center of all flavivirus capsid protein sequences and part of which may form an amphipathic alpha-helix. In the context of the full-length TBE genome, the deletions did not measurably affect protein expression and up to a deletion length of 16 amino acid residues, corresponding to almost 17% of mature protein C, viable virus was recovered. This virus was strongly attenuated but highly immunogenic in adult mice, revealing capsid protein C as a new and attractive target for the directed attenuation of flaviviruses. Apparently, the larger deletions interfered with the correct assembly of infectious virus particles, and this disturbance of virion assembly is likely to be the molecular basis of attenuation. However, all of the mutants carrying large deletions produced substantial amounts of subviral particles, which as judged from density gradient analyses were identical to recombinant subviral particles as obtained by the expression of the surface proteins prM and E alone. The structural and functional flexibility of protein C revealed in this study and its predicted largely alpha-helical conformation are reminiscent of capsid proteins of other enveloped viruses, such as alphaviruses (N-terminal domain of the capsid protein), retroviruses, and hepadnaviruses and suggest that all of these may belong to a common structural class, which is fundamentally distinct from the classical ␤-barrel structures of many icosahedral viral capsids. The possibility of attenuating flaviviruses by disturbing virus assembly and favoring the production of noninfectious but highly immunogenic subviral particles opens up a promising new avenue for the development of live flavivirus vaccines.Members of the genus Flavivirus, family Flaviviridae, such as yellow fever virus, Japanese encephalitis virus, West Nile virus, the dengue viruses, and tick-borne encephalitis (TBE) virus, cause major human health problems in large areas of the world (4). In spite of a long and successful history of vaccinations against some flavivirus diseases, there is a continuing demand for the development of new flavivirus vaccines. Flaviviruses are positive-stranded RNA viruses. The genome consists of a single approximately 11-kb-long RNA molecule that encodes all of the viral proteins in a single long open reading frame flanked by a rather short 5Ј and a somewhat longer 3Ј noncoding region (24). For many flaviviruses, including TBE virus, infectious cDNA clones have become available during the past two decades (43). This has made it possible to specifically manipulate the genomes of these viruses. Using this technology, a number of approaches to create attenuated flaviviruses that might be used as live virus vaccines have been pursued, including the construction of chimeric flaviviruses (see reference 2 and references cited there...

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Molecular epidemiology of tick-borne encephalitis virus inIxodes ricinus ticks in Lithuania

Han

Jucevičienė²,

Uzcátegui

et al. 2005

J. Med. Virol.

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In Lithuania, 171-645 serologically confirmed cases of tick-borne encephalitis occurred annually [Mickiene et al. (2001): Eur J Clin Microbiol Infect Dis 20:886-888] in 1993-1999, and the tick-borne encephalitis virus (TBEV) seroprevalence in the general population was found previously to be 3.0% [Juceviciene et al. (2002): J Clin Virol 25:23-27]. To assess the risk for TBEV virus infection in Lithuania and to characterize the agent a panel of 3,234 ticks combined into 436 pools [Juceviciene et al., 2005] were tested for presence of TBEV RNA by a nested RT-PCR targeting at the NS5 gene. Six pools were confirmed positive and the prevalence of the infected ticks was 0.2% (if one tick per pool [Juceviciene et al., 2005] was considered positive) and the proportion of positive tick pools was 1.4%. The prevalence of the infected ticks in the Panevezys, Siauliai, and Radviliskis regions (in central Lithuania) was 0.1%, 0.4%, and 1.7% corresponding with a higher TBE disease burden in these regions. The 252-nucleotide NS5-region amplicons, and a longer sequence (737 nucleotides) obtained from one sample from the PrM-E gene region, were sequenced. Phylogenetic analysis of the latter showed that all western type TBEV PrM-E sequences, including the Lithuanian strains, were monophyletic, showed no clustering and had very little variation. The NS5 sequences, although identical within one locality, did not show any mutations common to strains from the two Lithuanian regions, nor could any geographical clustering be found among western type TBEV strains from other areas.

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Characterization and complete genome sequences of high- and low-virulence variants of tick-borne encephalitis virus

Cited by 79 publications

References 42 publications

Mimicking live flavivirus immunization with a noninfectious RNA vaccine

Mimicking live flavivirus immunization with a noninfectious RNA vaccine

Capsid Protein C of Tick-Borne Encephalitis Virus Tolerates Large Internal Deletions and Is a Favorable Target for Attenuation of Virulence

Molecular epidemiology of tick-borne encephalitis virus inIxodes ricinus ticks in Lithuania

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