RESUMO
Previously different authors described various flavivirus mutants with high affinity to cell glycosaminoglycans and low neuroinvasiveness in mice that were obtained consequently passages in cell cultures or in ticks. In present study the analysis of TBEV isolates has shown existence of GAG-binding variants in natural virus population. Affinity to GAG has been evaluated by sorption on heparin-Sepharose. GAG-binding phenotype corresponds to such virus properties, like small plaque phenotype in PEK cells, absence of hemagglutination at pH 6.4, and low neuroinvasiveness in mice. Mutations increasing charge of E protein were necessary but not sufficient for acquisition of GAG-binding phenotype. Molecular modeling and molecular dynamics simulation have shown that the flexibility of E protein molecule could bear influence on the phenotypic manifestation of substitutions increasing charge of the virions.
Assuntos
Vírus da Encefalite Transmitidos por Carrapatos/genética , Produtos do Gene gag/metabolismo , Animais , Vírus da Encefalite Transmitidos por Carrapatos/patogenicidade , Encefalite Transmitida por Carrapatos/virologia , Variação Genética/genética , Testes de Hemaglutinação , Imunoeletroforese , Camundongos , Camundongos Endogâmicos BALB C , Mutação/genética , Fenótipo , Sefarose/análogos & derivados , Alinhamento de Sequência , Homologia de Sequência do Ácido Nucleico , Proteínas do Envelope Viral/genética , Proteínas do Envelope Viral/metabolismoRESUMO
Reverse transcription-polymerase chain reaction was used to develop a procedure with internal monitoring that may provide evidence for the absence of tick-borne encephalitis virus RNA in bioassays. The proposed procedure is useful in evaluating the safety and effectiveness of a tick-borne encephalitis vaccine.