RESUMO
Tick-borne encephalitis virus (TBEV) causes severe encephalitis in humans. It is endemic in one area of Japan; however no commercial vaccine is available in that country. In this Japan-based study, the efficacy of subviral particles (SPs) of TBEV administered by needle-free injector was evaluated as a vaccine candidate. Inoculation with SP-encoding DNA by needle-free injector induced neutralizing antibodies more efficiently than when administered by needle and syringe, and mice vaccinated with one dose by needle-free injector survived challenge with a lethal dose of TBEV. These results suggest that SP vaccines delivered by needle-free injector can protect against TBEV infection.
Assuntos
Anticorpos Antivirais/sangue , Vírus da Encefalite Transmitidos por Carrapatos/imunologia , Encefalite Transmitida por Carrapatos/prevenção & controle , Vacinas de DNA/administração & dosagem , Vacinas Virais/administração & dosagem , Animais , Anticorpos Neutralizantes/biossíntese , Anticorpos Antivirais/biossíntese , DNA Viral/genética , DNA Viral/imunologia , Vírus da Encefalite Transmitidos por Carrapatos/genética , Encefalite Transmitida por Carrapatos/imunologia , Encefalite Transmitida por Carrapatos/virologia , Humanos , Injeções a Jato , Japão , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Vacinação , Vacinas de DNA/imunologia , Vacinas Sintéticas/administração & dosagem , Vacinas Sintéticas/imunologia , Proteínas Virais/genética , Proteínas Virais/imunologia , Vacinas Virais/imunologiaRESUMO
Tick-borne encephalitis virus (TBEV) causes severe encephalitis in humans. The Sofjin-HO strain is the prototype strain of the TBEV Far-Eastern subtype and is highly pathogenic in a mouse model. In this study, we constructed replicons and infectious cDNA clones of the Sofjin-HO strain. The replication of the replicon RNA was confirmed, and infectious viruses were recovered from the infectious cDNA clone. The recombinant viruses showed similar virulence characteristics to those of the parental virus. While characterizing the replicon and infectious cDNA, several amino acid differences derived from cell culture adaptations were analysed. The amino acids differences at E position 496 and NS4A position 58 were found to affect viral replication. The Gly- or Ala-to-Glu substitution at E position 122 was shown to increase neuroinvasiveness in mice. These replicons and infectious cDNA clones are useful in revealing the viral molecular determinants involved in the replication and pathogenicity of TBEV.
Assuntos
Vírus da Encefalite Transmitidos por Carrapatos/genética , Encefalite Transmitida por Carrapatos/virologia , Replicon , Animais , Linhagem Celular , Cricetinae , DNA Complementar/genética , DNA Complementar/metabolismo , DNA Viral/genética , DNA Viral/metabolismo , Vírus da Encefalite Transmitidos por Carrapatos/classificação , Vírus da Encefalite Transmitidos por Carrapatos/patogenicidade , Vírus da Encefalite Transmitidos por Carrapatos/fisiologia , Feminino , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Virulência , Replicação ViralRESUMO
Tick-borne encephalitis virus (TBEV) is a zoonotic agent causing severe encephalitis in humans. Rodent species that are potential hosts for TBEV are widely distributed in various regions in Japan. In this study, we carried out large-scale epizootiological surveys in rodents from various areas of Japan. A total of 931 rodent and insectivore sera were collected from field surveys. Rodents seropositive for TBEV were found in Shimane Prefecture in Honshu and in several areas of Hokkaido Prefecture. These results emphasize the need for further epizootiological and epidemiological research of TBEV and preventive measures for emerging tick-borne encephalitis in Japan.
