Tick-borne encephalitis virus (TBEV) is a virus of the family Flaviviridae and has three subtypes: European or Western tick-borne encephalitis virus, Siberian tick-borne encephalitis virus and Far eastern tick-borne encephalitis virus (formerly known as Russian Spring Summer encephalitis virus). TBEV causes tick-borne encephalitis, a human viral disease of the central nervous system, typically presenting in meningitis, encephalitis or meningoencephilitis. Ixodid Ticks are the vector and reservoir for TBEV, with the main hosts being rodents, with humans being accidental hosts. The disease is endemic to Europe, Russia and Asia.
>gi|206570298|gb|ACI12930.1| capsid protein [Tick-borne encephalitis virus]
MARKAILKGKGGGPPRRVSKETAKKTRQSRVQMPN
Molecule Role :
Virmugen
Molecule Role Annotation :
A virus with a mutation in protein C is attenuated in mice and induced protection from challenge with wild type TBE virus (Kofler et al., 2002).
Molecule Role Annotation :
Series of plasmid constructs encoding different forms of the envelope glycoprotein E of the flavivirus tick-borne encephalitis virus were constructed. These included a secreted recombinant subviral particle, a secreted carboxyl-terminally truncated soluble homodimer, a nonsecreted full-length form, and an inefficiently secreted truncated form. Mice were immunized using both i.m. injection and Gene Gun-mediated application of plasmids. The functional immune response was evaluated by determining specific neutralizing and hemagglutination-inhibiting Ab activities and by challenging the mice with a lethal dose of the virus.The plasmid construct encoding a secreted subviral particle, which carries multiple copies of the protective Ag on its surface, was superior to the other constructs in terms of extent and functionality of the Ab response as well as protection against virus challenge (Aberle et al., 1999).
ncepur Adults vaccines were processed using filter-aided sample preparation (FASP). , protein cysteine disulfide bonds were reduced in 0.1M dithiothreitol (DTT) in 8 M urea/0.1 M Tris/HCl (pH 8.5), and 50 mM iodoacetamide was used to alkylate cysteine residues (Salat et al., 2020).
j. Immunization Route
Intramuscular injection (i.m.)
k. Description
Encepur is a -virus formalin-inactivated TBEV vaccines avaliable in the European Union and European Economic Area. Vaccination induces neutralizing antibodies directed against the main antigenic determinant of the viral particle, the E protein.(Salat et al., 2020)
Vaccination Protocol:
Groups of 16 BALB/c mice each received primary and booster immunizations spaced 4 wk apart. Plasmids were purified and administered i.m. (100 µg/dose) or by particle bombardment with DNA-coated gold beads (2 µg/dose) using the helium-powered Helios Gene Gun delivery system. Intramuscular inoculation of DNA in saline was done as a 100-µl injection in the right quadriceps. For Gene Gun inoculation, 1.0 µg of the same DNA was coupled to 0.5 mg of 1.0-µm-diameter gold particles, as recommended by the manufacturer (Bio-Rad). DNA-coated microcarriers were delivered into the abdominal epidermis of mice using the Gene Gun at a helium pressure setting of 400 psi. Mice immunized with the commercial TBE vaccine received 0.2 ml s.c. inoculations containing 1 µg formalin-inactivated virus (FSME Immun Inject, Baxter-Immuno, Vienna, Austria) (Aberle et al., 1999).
Challenge Protocol:
Mice were subsequently challenged by i.p. inoculation with 1000 LD50 of the highly mouse-pathogenic TBE virus strain Hypr. (Aberle et al., 1999).
Efficacy:
The plasmid construct encoding a secreted subviral particle, which carries multiple copies of the protective Ag on its surface, was superior to the other constructs in terms of extent and functionality of the Ab response as well as protection against virus challenge (Aberle et al., 1999).
4. TBEV Virus Like Particle Vaccine
a. Type:
Virus Particle Vaccine
b. Status:
Research
c. Host Species for Licensed Use:
None
d. Host Species as Laboratory Animal Model:
Mouse
e. Antigen
Atructural (Core/prM/E) and non-structural (NS2B/NS3Pro) proteins of TBEV (Tang et al., 2023)
f. Preparation
Expi293 cells were diluted to a density of 1.5 × 106 cells/mL before transfection with pcDNA3.1-NS2B/NS3Pro and pcDNA3.1-C/prM/E at a ratio of 1:2, then the cells were cultivated at 37°C in an atmosphere of 5% CO2, with agitation at 150 rpm. For the production of VLPs, the plasmids (480 μg) were added to polyethylenimine hydrochloride (1,350 μg; Polysciences) in 10 mL of Expi293 medium and incubated for 10 min, the mixture was then added to 470 mL of cell solution. The transfected cells were harvested at 4 days post-transfection and the supernatant was collected by two successive centrifugation steps at 400 ×g for 10 min at 4°C, then 10,000 ×g for 10 min at 4°C. The proteins in the supernatant were precipitated using 8% (wt/vol) polyethylene glycol 8000 and incubated overnight at 4°C. (Tang et al., 2023)
g. Immunization Route
Intramuscular injection (i.m.)
h. Description
Virus-like particle-based vaccine co-expressing the structural (Core/prM/E) and non-structural (NS2B/NS3Pro) proteins of TBEV confers complete protection against TBEV in mice. (Tang et al., 2023)
i.
Mouse Response
Vaccination Protocol:
Eight-week-old male C57BL/6 mice were used for the immunization and viral neutralization experiments. The mice (n=5 per group) were immunized by twice intramuscular injections with PBS or 10 μg of VLPs.Six to eight-week-old male IFNAR-/- mice were used for immunization and challenge experiments. The mice (n=10 per group) were immunized with PBS or 10 μg of VLPs. (Tang et al., 2023)
Immune Response:
The results of ELISA demonstrated that vaccination with the VLPs stimulated a high total serum IgG response, and the prime antibody response increased by 2.5-fold following boost immunization (Fig. 2C). Additionally, the antibodies elicited by the VLPs significantly neutralized both TBEV-FE and TBEV-Eu infections in BHK-21 cells, with inhibition rates reaching up to 90%. Altogether, these findings suggested that the VLPs exhibited superior immunogenicity and induced high levels of humoral immunity (IgG and NAb) against different subtypes of TBEV. (Tang et al., 2023)
Challenge Protocol:
VLP-immunized IFNAR−/− mice were challenged with a lethal dose (3.2×106 PFU) of the WH2012 strain of TBEV by intramuscular injection after two weeks post-boost immunization with 10 μg VLPs. (Tang et al., 2023)
Efficacy:
The infected mice displayed some abnormal behaviors, such as listlessness, circling and freezing, and all the infected mice died within 8 dpi. In contrast, immunized mice survived the challenge, and their weights did not decrease significantly. The viremia of the control group was notably high (7.9×104 TCID50/mL), with average values in the brain and intestinal tissues reaching 1.0×10^7 and 5.0×10^5 TCID50/mL, respectively. In contrast, the mice that had been immunized with the VLPs did not exhibit any neurological symptoms and the viral loads in the serum samples, brain, and intestinal tissues were negligible or undetectable. (Tang et al., 2023)
5. Tick-borne Encephalitis Virus C protein mutant vaccine
Persistence:
A C protein mutant is attenuated in mice (Kofler et al., 2002).
Efficacy:
A C protein mutant induced protection in mice from challenge with wild type TBEV (Kofler et al., 2002).
IV. References
1. Aberle et al., 1999: Aberle JH, Aberle SW, Allison SL, Stiasny K, Ecker M, Mandl CW, Berger R, Heinz FX. A DNA immunization model study with constructs expressing the tick-borne encephalitis virus envelope protein E in different physical forms. Journal of immunology (Baltimore, Md. : 1950). 1999; 163(12); 6756-6761. [PubMed: 10586074].
3. Dmitriev et al., 1996: Dmitriev IP, Khromykh AA, Ignatyev GM, Gainullina MN, Ageenko VA, Dryga SA, Vorobyeva MS, Sandakhchiev LS. Immunization with recombinant vaccinia viruses expressing structural and part of the nonstructural region of tick-borne encephalitis virus cDNA protect mice against lethal encephalitis. Journal of biotechnology. 1996; 44(1-3); 97-103. [PubMed: 8717392].
4. Kofler et al., 2002: Kofler RM, Heinz FX, Mandl CW. Capsid protein C of tick-borne encephalitis virus tolerates large internal deletions and is a favorable target for attenuation of virulence. Journal of virology. 2002; 76(7); 3534-3543. [PubMed: 11884577].
5. Stenkova et al., 2017: Stenkova AM, Chopenko NS, Davydova LA, Mazeika AN, Bystritskaya EP, Portnyagina OY, Anastyuk SD, Kulbatskii DS, Lyukmanova EN, Dolgikh DA, Kostetsky EY, Sanina NM. Engineering of Chimeric Protein Based on E Protein Domain III of Tick- Borne Encephalitis Virus and OmpF Porin of Yersinia pseudotuberculosis. Protein and peptide letters. 2017; 24(10); 974-981. [PubMed: 28741465].
