A Putative Host Cell Receptor for Tick-Borne Encephalitis Virus Identified by Anti-Idiotypic Antibodies and Virus Affinoblotting

Kopecký, Jan; Grubhoffer, Libor; Kovář, Vojtěch; Jindrák, Libor; Vokurková, Doris

doi:10.1159/000024954

Cited by 31 publications

(14 citation statements)

References 23 publications

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“…The structural proteins of flaviviruses, especially the E proteins, have been reported to be important for virulence (Kopecký et al, 1999;Kozlovskaya et al, 2010;Navarro-Sanchez et al, 2003). To examine whether the structural proteins are determinants of virulence in mice, Sofjin-IC/ oshimaCME and Oshima-IC/sofjinCME were constructed by replacement of the coding region for most of the structural proteins (nt 240-2291) with that of Oshima-IC-pt Five adult C57BL/6 mice were infected with Sofjin-IC/oshimaCME and Oshima-IC/sofjinCME, and 10 mice were infected with the other viruses.…”

Section: Resultsmentioning

confidence: 99%

Variable region of the 3′ UTR is a critical virulence factor in the Far-Eastern subtype of tick-borne encephalitis virus in a mouse model

Sakai

Yoshii

Sunden

et al. 2014

Journal of General Virology

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Tick-borne encephalitis virus (TBEV) is a major arbovirus that causes thousands of cases of severe neurological illness in humans annually. However, virulence factors and pathological mechanisms of TBEV remain largely unknown. To identify the virulence factors, we constructed chimeric viruses between two TBEV strains of the Far-Eastern subtype, Sofjin-HO (highly pathogenic) and Oshima 5-10 (low pathogenic). The replacement of the coding region for the structural and non-structural proteins from Sofjin into Oshima showed a partial increase of the viral pathogenicity in a mouse model. Oshima-based chimeric viruses with the variable region of the 39 UTR of Sofjin, which had a deletion of 207 nt, killed 100 % of mice and showed almost the same virulence as Sofjin. Replacement of the variable region of the 39 UTR from Sofjin into Oshima did not increase viral multiplication in cultured cells and a mouse model at the early phase of viral entry into the brain. At the terminal phase of viral infection in mice, the virus titre of the Oshima-based chimeric virus with the variable region of the 39 UTR of Sofjin reached a level identical to that of Sofjin and showed a similar histopathological change in the brain tissue. This is the first report to show that the variable region of the 39 UTR is a critical virulence factor in mice. These findings encourage further study to understand the mechanisms of the pathogenicity of TBEV, and to develop preventative and therapeutic strategies for tick-borne encephalitis.

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Section: Resultsmentioning

confidence: 99%

Variable region of the 3′ UTR is a critical virulence factor in the Far-Eastern subtype of tick-borne encephalitis virus in a mouse model

Sakai

Yoshii

Sunden

et al. 2014

Journal of General Virology

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“…Most flaviviruses replicate in vertebrate and arthropod cells and exhibit a wide species and tissue tropism. Numerous candidate receptor proteins with a molecular mass of 40 to 80 kDa have been found to associate with flaviviruses in binding assays (19,22,27,36,44). Furthermore, an important role of heparan sulfate has also been demonstrated for the attachment of dengue-2 virus to vertebrate cells (7).…”

mentioning

confidence: 99%

Substitutions at the Putative Receptor-Binding Site of an Encephalitic Flavivirus Alter Virulence and Host Cell Tropism and Reveal a Role for Glycosaminoglycans in Entry

Lee

Lobigs

2000

J Virol

142

124

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The flavivirus receptor-binding domain has been putatively assigned to a hydrophilic region (FG loop) Virus attachment to the host cell is the first stage of the virus replication cycle. It requires the molecular interaction between the virion surface and a host cell receptor and is often the basis for viral species and tissue tropisms as well as virulence properties. The cellular receptors for some viruses have been defined and reveal diverse strategies for virus attachment, ranging from binding to specific cell surface proteins to attachment via widely distributed carbohydrate moieties, such as sialic acid and heparan sulfate (for a review, see reference 48). For a large number of viruses, however, specific host cell receptors have not been identified. The use of multiple receptors on individual or different cells could be one reason for this lack of knowledge. This scenario has been proposed for the attachment of flaviviruses (35), a genus of approximately 70 mainly arthropod-borne, enveloped RNA viruses. Most flaviviruses replicate in vertebrate and arthropod cells and exhibit a wide species and tissue tropism. Numerous candidate receptor proteins with a molecular mass of 40 to 80 kDa have been found to associate with flaviviruses in binding assays (19,22,27,36,44). Furthermore, an important role of heparan sulfate has also been demonstrated for the attachment of dengue-2 virus to vertebrate cells (7). Interestingly, cell surface glycosaminoglycans (GAGs) are exploited as attachment molecules by other viruses in a process thought to concentrate virus particles at the cell surface for subsequent binding to high-affinity receptors (for a review, see reference 2). No experimental evidence on the use or nature of a high-affinity receptor for any of the flaviviruses exists at present.Flavivirus attachment and entry are mediated by the envelope (E) protein (ϳ50 kDa), the major glycoprotein on the flavivirus particle (for reviews, see references 6 and 33). The E protein forms an oligomer with the small membrane (M) protein (ϳ8 kDa) and constitutes most of the accessible virion surface; this is reflected in the dominance of the E protein as target antigen for virus-neutralizing and protective antibodies (33). The definition of the crystal structure of the ectodomain of the E protein of the flavivirus tick-borne encephalitis virus (TBE) (37), in combination with phenotypic analyses of E protein variants, has shed light on functional domains and mechanisms involved in flavivirus attachment and entry (for a review, see reference 33). An investigation by one of us on genotypic changes associated with host cell adaptation of the encephalitic flavivirus Murray Valley encephalitis virus (MVE) suggested an important role for residue 390 in the E protein in cell tropism and virulence (25). Asp 390 found in the prototype virus was altered to His, Gly, Ala, or Asn after passage of MVE in a human adenocarcinoma (SW13) cell line, resulting in improved growth in the human cell line as well as virulence attenuation in mice. Resi...

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“…The third cluster is on the upper and distal-lateral surface of domain III, which has been proposed to be involved in receptor binding, and this may be the functional basis of how these mutations influence the virulence of flaviviruses. Aside from dengue type 2 virus, for which a requirement for heparan sulfate binding has been demonstrated (2), no specific flavivirus cellular receptors have been definitively identified, but some reports indicate the presence of various cell surface proteins with specific binding affinities for different flaviviruses (10,11,19,27). An involvement of the lateral surface of domain III in cell attachment is suggested by several lines of indirect evidence (12,22), including the immunoglobulin-like fold of this domain, which is characteristically found in many proteins with specific binding functions, the high density of charged surface residues on the lateral surface, the presence of an RGD motif in some mosquito-borne flaviviruses (which is known in other cases to be recognized by members of the integrin protein familiy), and the identification of mutations in this region in host range mutants (14) and mutants with altered virulence properties (1,3,4,8,9,13,26).…”

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confidence: 99%

Attenuation of Tick-Borne Encephalitis Virus by Structure-Based Site-Specific Mutagenesis of a Putative Flavivirus Receptor Binding Site

Mandl

Allison

Holzmann

et al. 2000

J Virol

127

103

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The impact of a specific region of the envelope protein E of tick-borne encephalitis (TBE) virus on the biology of this virus was investigated by a site-directed mutagenesis approach. The four amino acid residues that were analyzed in detail (E308 to E311) are located on the upper-lateral surface of domain III according to the X-ray structure of the TBE virus protein E and are part of an area that is considered to be a potential receptor binding determinant of flaviviruses. Mutants containing single amino acid substitutions, as well as combinations of mutations, were constructed and analyzed for their virulence in mice, growth properties in cultured cells, and genetic stability. The most significant attenuation in mice was achieved by mutagenesis of threonine 310. Combining this mutation with deletion mutations in the 3-noncoding region yielded mutants that were highly attenuated. The biological effects of mutation Thr 310 to Lys, however, could be reversed to a large degree by a mutation at a neighboring position (Lys 311 to Glu) that arose spontaneously during infection of a mouse. Mutagenesis of the other positions provided evidence for the functional importance of residue 308 (Asp) and its charge interaction with residue 311 (Lys), whereas residue 309 could be altered or even deleted without any notable consequences. Deletion of residue 309 was accompanied by a spontaneous second-site mutation (Phe to Tyr) at position 332, which in the three-dimensional structure of protein E is spatially close to residue 309. The information obtained in this study is relevant for the development of specific attenuated flavivirus strains that may serve as future live vaccines.Tick-borne encephalitis (TBE) virus is a human pathogenic member of the genus Flavivirus (family Flaviviridae) (31). Many members of this genus can cause severe human diseases, the most important representatives besides TBE virus being the mosquito-borne viruses yellow fever (YF) virus, Japanese encephalitis (JE) virus, and the four serotypes of dengue virus (18). In spite of the availability of attenuated live vaccines (in the case of YF virus) and formalin-inactivated killed vaccines (TBE virus, JE virus) which have proven to be effective for the prevention of flavivirus infections, there is a strong demand for the development of novel and improved vaccines against these and other flavivirus infections. For the rational design of live vaccines, a detailed understanding of the molecular basis of virulence and pathogenesis is a major goal. With the availability of modern molecular techniques and high-resolution structural information, it is now possible to alter viral structures in a specific and rational way in order to understand structurefunction relationships. This knowledge can then be applied to achieve the desired biological property, such as attenuation of the virus.Flavivirus virions are relatively simple particles consisting of a nucleocapsid composed of a single capsid protein (C) surrounded by a lipid membrane that contains two viral protein...

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A Putative Host Cell Receptor for Tick-Borne Encephalitis Virus Identified by Anti-Idiotypic Antibodies and Virus Affinoblotting

Cited by 31 publications

References 23 publications

Variable region of the 3′ UTR is a critical virulence factor in the Far-Eastern subtype of tick-borne encephalitis virus in a mouse model

Variable region of the 3′ UTR is a critical virulence factor in the Far-Eastern subtype of tick-borne encephalitis virus in a mouse model

Substitutions at the Putative Receptor-Binding Site of an Encephalitic Flavivirus Alter Virulence and Host Cell Tropism and Reveal a Role for Glycosaminoglycans in Entry

Attenuation of Tick-Borne Encephalitis Virus by Structure-Based Site-Specific Mutagenesis of a Putative Flavivirus Receptor Binding Site

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