scholarly journals The envelope protein of tick-borne encephalitis virus influences neuron entry, pathogenicity, and vaccine protection

2020 ◽  
Vol 17 (1) ◽  
Author(s):  
Richard Lindqvist ◽  
Ebba Rosendal ◽  
Elvira Weber ◽  
Naveed Asghar ◽  
Sarah Schreier ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Encephalitis Virus ◽  
Chimeric Virus ◽  
E Protein ◽  
Tick Borne Encephalitis ◽  
Neutralizing Capacity ◽  
Tbev Strain ◽  
Primary Mouse ◽  
Tick Borne Encephalitis Virus

Abstract Background Tick-borne encephalitis virus (TBEV) is considered to be the medically most important arthropod-borne virus in Europe. The symptoms of an infection range from subclinical to mild flu-like disease to lethal encephalitis. The exact determinants of disease severity are not known; however, the virulence of the strain as well as the immune status of the host are thought to be important factors for the outcome of the infection. Here we investigated virulence determinants in TBEV infection. Method Mice were infected with different TBEV strains, and high virulent and low virulent TBEV strains were chosen. Sequence alignment identified differences that were cloned to generate chimera virus. The infection rate of the parental and chimeric virus were evaluated in primary mouse neurons, astrocytes, mouse embryonic fibroblasts, and in vivo. Neutralizing capacity of serum from individuals vaccinated with the FSME-IMMUN® and Encepur® or combined were evaluated. Results We identified a highly pathogenic and neurovirulent TBEV strain, 93/783. Using sequence analysis, we identified the envelope (E) protein of 93/783 as a potential virulence determinant and cloned it into the less pathogenic TBEV strain Torö. We found that the chimeric virus specifically infected primary neurons more efficiently compared to wild-type (WT) Torö and this correlated with enhanced pathogenicity and higher levels of viral RNA in vivo. The E protein is also the major target of neutralizing antibodies; thus, genetic variation in the E protein could influence the efficiency of the two available vaccines, FSME-IMMUN® and Encepur®. As TBEV vaccine breakthroughs have occurred in Europe, we chose to compare neutralizing capacity from individuals vaccinated with the two different vaccines or a combination of them. Our data suggest that the different vaccines do not perform equally well against the two Swedish strains. Conclusions Our findings show that two amino acid substitutions of the E protein found in 93/783, A83T, and A463S enhanced Torö infection of neurons as well as pathogenesis and viral replication in vivo; furthermore, we found that genetic divergence from the vaccine strain resulted in lower neutralizing antibody titers in vaccinated individuals.

scholarly journals The Envelope Protein of Tick-Borne Encephalitis Virus Influence Neuron Entry, Pathogenicity and Vaccine Protection

2020 ◽  
Author(s):  
Richard Lindqvist ◽  
Ebba Rosendal ◽  
Naveed Asghar ◽  
Sarah Schreier ◽  
Annasara Lenman ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Encephalitis Virus ◽  
Chimeric Virus ◽  
E Protein ◽  
Tick Borne Encephalitis ◽  
Neutralizing Capacity ◽  
Tbev Strain ◽  
Primary Mouse ◽  
Tick Borne Encephalitis Virus

Abstract Background: Tick-borne encephalitis virus (TBEV) is considered to be the medically most important arthropod-borne virus in Europe. The symptoms of an infection ranges from subclinical to mild flu-like disease to lethal encephalitis. The exact determinants of disease severity are not known, however, the virulence of the strain as well as the immune status of the host are thought to be important factors for the outcome of the infection. Here we investigated virulence determinants in TBEV infection.Method: Mice were infected with different TBEV strains, and high virulent and low virulent TBEV were chosen. Sequence alignment were used to identify differences that were cloned to generate chimera virus. The infection rate of the parental and chimeric virus were evaluated in primary mouse neurons, astrocytes and MEFs. Neutralizing capacity of serum from individuals vaccinated with the FSME-IMMUN® and Encepur® or combined were evaluated.Results: We identified a highly pathogenic and neurovirulent TBEV strain, 93/783. Using sequence analysis, we identified the envelope (E) protein of 93/783 as a potential virulence determinant and cloned it into the less pathogenic TBEV strain Torö. We found that the chimeric virus specifically infected primary neurons more efficiently compared to wild type (WT) Torö and this correlated with enhanced pathogenicity in vivo. The E protein is also the major target of neutralizing antibodies, thus genetic variation in the E protein could influence the efficiency of the two available vaccines, FSME-IMMUN® and Encepur®. As TBEV vaccine breakthroughs have occurred in Europe, we choose to compare neutralizing capacity from individuals vaccinated with the two different vaccines or a combination of them. Our data suggest that the different vaccines do not perform equally well against the two Swedish strains.Conclusions: Our findings show that two amino acid substitutions of the E protein found in 93/783, A83T and A463S, enhanced Torö infection of neurons as well as pathogenesis in vivo, furthermore we found that genetic divergence from the vaccine strain resulted in lower neutralizing antibody titers in vaccinated individuals.

scholarly journals Spectrum of antiviral activity of 4-aminopyrimidine N-oxides against a broad panel of tick-borne encephalitis virus strains

2020 ◽  
Vol 28 ◽  
pp. 204020662094346
Author(s):  
Evgenia V Dueva ◽  
Ksenia K Tuchynskaya ◽  
Liubov I Kozlovskaya ◽  
Dmitry I Osolodkin ◽  
Kseniya N Sedenkova ◽  
...  
Keyword(s):  
Encephalitis Virus ◽  
Northern Eurasia ◽  
Virus Particles ◽  
E Protein ◽  
Tick Borne Encephalitis ◽  
Tbev Strain ◽  
Amino Phenol ◽  
Tick Borne Encephalitis Virus ◽  
Immature Virus

Tick-borne encephalitis is an important human arbovirus neuroinfection spread across the Northern Eurasia. Inhibitors of tick-borne encephalitis virus (TBEV) strain Absettarov, presumably targeting E protein n-octyl-β-d-glucoside (β-OG) pocket, were reported earlier. In this work, these inhibitors were tested in vitro against seven strains representing three main TBEV subtypes. The most potent compound, 2-[(2-methyl-1-oxido-5,6,7,8-tetrahydroquinazolin-4-yl)amino]-phenol, showed EC50 values lower than 22 µM against all the tested strains. Nevertheless, EC50 values for virus samples of certain strains demonstrated a substantial variation, which appeared to be consistent with the presence of E protein not only in infectious virions, but also in non-infectious and immature virus particles, protein aggregates, and membrane complexes.

scholarly journals Impact of Quaternary Organization on the Antigenic Structure of the Tick-Borne Encephalitis Virus Envelope Glycoprotein E

2009 ◽  
Vol 83 (17) ◽  
pp. 8482-8491 ◽  
Author(s):  
Stefan Kiermayr ◽  
Karin Stiasny ◽  
Franz X. Heinz
Keyword(s):  
Neutralizing Antibodies ◽  
Encephalitis Virus ◽  
Antigenic Structure ◽  
Icosahedral Symmetry ◽  
Virus Envelope ◽  
E Protein ◽  
Tick Borne Encephalitis ◽  
Tick Borne Encephalitis Virus ◽  
Virion Surface ◽  
Subviral Particles

ABSTRACT The envelope protein E of flaviviruses mediates both receptor-binding and membrane fusion. At the virion surface, 180 copies of E are tightly packed and organized in a herringbone-like icosahedral structure, whereas in noninfectious subviral particles, 60 copies are arranged in a T=1 icosahedral symmetry. In both cases, the basic building block is an E dimer which exposes the binding sites for neutralizing antibodies at its surface. It was the objective of our study to assess the dependence of the antigenic structure of E on its quaternary arrangement, i.e., as part of virions, recombinant subviral particles, or soluble dimers. For this purpose, we used a panel of 11 E protein-specific neutralizing monoclonal antibodies, mapped to distinct epitopes in each of the three E protein domains, and studied their reactivity with the different soluble and particulate forms of tick-borne encephalitis virus E protein under nondenaturing immunoassay conditions. Significant differences in the reactivities with these forms were observed that could be related to (i) limited access of certain epitopes at the virion surface; (ii) limited occupancy of epitopes in virions due to steric hindrance between antibodies; (iii) differences in the avidity to soluble forms compared to the virion, presumably related to the flexibility of E at its domain junctions; and (iv) modulations of the external E protein surface through interactions with its stem-anchor structure. We have thus identified several important factors that influence the antigenicity of the flavivirus E protein and have an impact on the interaction with neutralizing antibodies.

scholarly journals Molecular Basis of the Divergent Immunogenicity of Two Pediatric Tick-Borne Encephalitis Virus Vaccines

2015 ◽  
Vol 90 (4) ◽  
pp. 1964-1972 ◽  
Author(s):  
Yvonne Beck ◽  
Richard Fritz ◽  
Klaus Orlinger ◽  
Stefan Kiermayr ◽  
Reinhard Ilk ◽  
...  
Keyword(s):  
Vaccine Strain ◽  
Neutralizing Antibodies ◽  
Three Dimensional ◽  
Neutralizing Antibody ◽  
Vaccine Virus ◽  
Encephalitis Virus ◽  
Hinge Region ◽  
E Protein ◽  
Tick Borne Encephalitis ◽  
Tick Borne Encephalitis Virus

ABSTRACTStudies evaluating the immunogenicity of two pediatric tick-borne encephalitis virus (TBEV) vaccines have reported contradictory results. These vaccines are based on two different strains of the European TBEV subtype: FSME-Immun Junior is based on the Neudörfl (Nd) strain, whereas Encepur Children is based on the Karlsruhe (K23) strain. The antibody (Ab) response induced by these two vaccines might be influenced by antigenic differences in the envelope (E) protein, which is the major target of neutralizing antibodies. We used an established hybrid virus assay platform to compare the levels of induction of neutralizing antibodies against the two vaccine virus strains in children aged 1 to 11 years who received two immunizations with FSME-Immun Junior or Encepur Children. The influence of amino acid differences between the E proteins of the Nd and K23 vaccine strains was investigated by mutational analyses and three-dimensional computer modeling. FSME-Immun Junior induced 100% seropositivity and similar neutralizing antibody titers against hybrid viruses containing the TBEV E protein of the two vaccine strains. Encepur Children induced 100% seropositivity only against the hybrid virus containing the E protein of the homologous K23 vaccine strain. Antibody responses induced by Encepur Children to the hybrid virus containing the E protein of the heterologous Nd strain were substantially and significantly (P< 0.001) lower than those to the K23 vaccine strain hybrid virus. Structure-based mutational analyses of the TBEV E protein indicated that this is due to a mutation in the DI-DII hinge region of the K23 vaccine strain E protein which may have occurred during production of the vaccine seed virus and which is not present in any wild-type TBE viruses.IMPORTANCEOur data suggest that there are major differences in the abilities of two European subtype pediatric TBEV vaccines to induce antibodies capable of neutralizing heterologous TBEV strains. This is a result of a mutation in the DI-DII hinge region of the E protein of the K23 vaccine virus strain used to manufacture Encepur Children which is not present in the Nd strain used to manufacture FSME-Immun Junior or in any other known naturally occurring TBEVs.

scholarly journals In Vivo Characterization of Tick-Borne Encephalitis Virus in Bank Voles (Myodes glareolus)

Viruses ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1069 ◽  
Author(s):  
Michelitsch ◽  
Tews ◽  
Klaus ◽  
Bestehorn-Willmann ◽  
Dobler ◽  
...  
Keyword(s):  
Bank Vole ◽  
Whole Blood ◽  
Clinical Signs ◽  
Encephalitis Virus ◽  
Myodes Glareolus ◽  
Bank Voles ◽  
Tick Borne Encephalitis ◽  
Tbev Strain ◽  
Tick Borne Encephalitis Virus

Tick-borne encephalitis is the most important tick-transmitted zoonotic virus infection in Eurasia, causing severe neurological symptoms in humans. The causative agent, the tick-borne encephalitis virus (TBEV), circulates between ticks and a variety of mammalian hosts. To study the interaction between TBEV and one of its suspected reservoir hosts, bank voles of the Western evolutionary lineage were inoculated subcutaneously with either one of eight TBEV strains or the related attenuated Langat virus, and were euthanized after 28 days. In addition, a subset of four strains was characterized in bank voles of the Carpathian linage. Six bank voles were inoculated per strain, and were housed together in groups of three with one uninfected in-contact animal each. Generally, most bank voles did not show any clinical signs over the course of infection. However, one infected bank vole died and three had to be euthanized prematurely, all of which had been inoculated with the identical TBEV strain (Battaune 17-H9, isolated in 2017 in Germany from a bank vole). All inoculated animals seroconverted, while none of the in-contact animals did. Viral RNA was detected via real-time RT-PCR in the whole blood samples of 31 out of 74 inoculated and surviving bank voles. The corresponding serum sample remained PCR-negative in nearly all cases (29/31). In addition, brain and/or spine samples tested positive in 11 cases, mostly correlating with a positive whole blood sample. Our findings suggest a good adaption of TBEV to bank voles, combining in most cases a low virulence phenotype with detectable virus replication and hinting at a reservoir host function of bank voles for TBEV.

scholarly journals The serological response and long-lasting resistance against infection with louping-ill virus in sheep immunized with a highly attenuated tick-borne encephalitis virus

1969 ◽  
Vol 67 (4) ◽  
pp. 731-738 ◽  
Author(s):  
V. Mayer ◽  
D. Blaškovič ◽  
E. Ernek ◽  
H. Libíková
Keyword(s):  
Neutralizing Antibodies ◽  
Encephalitis Virus ◽  
Serological Response ◽  
Immune Control ◽  
Summer Period ◽  
Tick Borne Encephalitis ◽  
Louping Ill ◽  
Tick Borne Encephalitis Virus

SUMMARYThe vaccination of sheep with one dose of the monkey-and mouse-attenuated tick-borne encephalitis virus (the Hy-HK 28 ‘2’ clone) causes seroconversion from negative into positive in 85% of animals. In sheep with pre-existing virus-neutralizing antibodies and increas of their titres was observed in 81%. The antibodies persisted for at least 12 months after the vaccination and during the summer period of grazing the number of serologically positive animals even increased.The vaccinated animals, in contrast to the non-immune control sheep, developed no viraemia after challenge with the virulent louping-ill virus, performed 11 months after immunization.

scholarly journals Molecular Basis of a Protective/Neutralizing Monoclonal Antibody Targeting Envelope Proteins of both Tick-Borne Encephalitis Virus and Louping Ill Virus

2019 ◽  
Vol 93 (8) ◽  
Author(s):  
Xu Yang ◽  
Jianxun Qi ◽  
Ruchao Peng ◽  
Lianpan Dai ◽  
Ernest A. Gould ◽  
...  
Keyword(s):  
Structural Analysis ◽  
Encephalitis Virus ◽  
Infection Rates ◽  
E Proteins ◽  
E Protein ◽  
Tick Borne Encephalitis ◽  
The Family ◽  
Lateral Ridge ◽  
Louping Ill ◽  
Tick Borne Encephalitis Virus

ABSTRACT Tick-borne encephalitis virus (TBEV) and louping ill virus (LIV) are members of the tick-borne flaviviruses (TBFVs) in the family Flaviviridae which cause encephalomeningitis and encephalitis in humans and other animals. Although vaccines against TBEV and LIV are available, infection rates are rising due to the low vaccination coverage. To date, no specific therapeutics have been licensed. Several neutralizing monoclonal antibodies (MAbs) show promising effectiveness in the control of TBFVs, but the underlying molecular mechanisms are yet to be characterized. Here, we determined the crystal structures of the LIV envelope (E) protein and report the comparative structural analysis of a TBFV broadly neutralizing murine MAb (MAb 4.2) in complex with either the LIV or TBEV E protein. The structures reveal that MAb 4.2 binds to the lateral ridge of domain III of the E protein (EDIII) of LIV or TBEV, an epitope also reported for other potently neutralizing MAbs against mosquito-borne flaviviruses (MBFVs), but adopts a unique binding orientation. Further structural analysis suggested that MAb 4.2 may neutralize flavivirus infection by preventing the structural rearrangement required for membrane fusion during virus entry. These findings extend our understanding of the vulnerability of TBFVs and other flaviviruses (including MBFVs) and provide an avenue for antibody-based TBFV antiviral development. IMPORTANCE Understanding the mechanism of antibody neutralization/protection against a virus is crucial for antiviral countermeasure development. Tick-borne encephalitis virus (TBEV) and louping ill virus (LIV) are tick-borne flaviviruses (TBFVs) in the family Flaviviridae. They cause encephalomeningitis and encephalitis in humans and other animals. Although vaccines for both viruses are available, infection rates are rising due to low vaccination coverage. In this study, we solved the crystal structures of the LIV envelope protein (E) and a broadly neutralizing/protective TBFV MAb, MAb 4.2, in complex with E from either TBEV or LIV. Key structural features shared by TBFV E proteins were analyzed. The structures of E-antibody complexes showed that MAb 4.2 targets the lateral ridge of both the TBEV and LIV E proteins, a vulnerable site in flaviviruses for other potent neutralizing MAbs. Thus, this site represents a promising target for TBFV antiviral development. Further, these structures provide important information for understanding TBFV antigenicity.

scholarly journals Tick-Borne Encephalitis Virus-Neutralizing Antibodies in Different Immunoglobulin Preparations

2012 ◽  
Vol 19 (4) ◽  
pp. 623-625 ◽  
Author(s):  
Philip O. Rabel ◽  
Christina B. Planitzer ◽  
Maria R. Farcet ◽  
Thomas R. Kreil
Keyword(s):  
Intravenous Immunoglobulin ◽  
Primary Immunodeficiency ◽  
Neutralizing Antibodies ◽  
Encephalitis Virus ◽  
Geographic Variability ◽  
Tick Borne Encephalitis ◽  
Immunoglobulin Preparations ◽  
Tick Borne Encephalitis Virus ◽  
Antibody Specificities ◽  
The Given

ABSTRACTPatients with primary immunodeficiency (PIDs) depend on the presence of a variety of antibody specificities in intravenous immunoglobulin (IVIG). Using the tick-borne encephalitis virus (TBEV), geographic variability in IVIG antibody content was shown. Care should therefore be exercised when treating PIDs in a given geography, as only locally sourced plasma contains the antibody specificities against the circulating pathogens in the given locality.

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