RESUMO
Live attenuated rubella vaccine is used for vaccination. Temperature-sensitive (ts) phenotype was proved for almost all rubella vaccine strains, and the acquisition of the ts phenotype during cold adaptation was strongly correlated with the attenuation of the wild-type viruses. Nevertheless, the molecular mechanisms of the attenuation have been insufficiently understood for rubella virus. Study ofthese mechanisms, identifying genotypic markers of attenuation, which together with the sequence analyses could be used for genetic stability control of vaccine strains, is still of current interest. In this work, we determined nearly complete genome sequences of attenuated (ca) and the wildtype progenitor (wt) of the rubella virus strain C-77 isolated in Russia. Possible genetic determinants of attenuation were detected. Thus, 13 nucleotide differences leading to 6 amino acid substitutions were found. Four amino acid substitutions were found to be almost unique. Special consideration should be given to Tyr1042Cys substitution in the protease domain of C-77 strain, because it most probably plays the crucial role in acquisition of ts-phenotype.
Assuntos
Adaptação Fisiológica , Vírus da Rubéola , Rubéola (Sarampo Alemão) , Temperatura , Vacinas Atenuadas/genética , Adaptação Fisiológica/genética , Substituição de Aminoácidos/genética , Animais , Chlorocebus aethiops , Temperatura Baixa , Genoma Viral , Humanos , Fenótipo , Filogenia , Rubéola (Sarampo Alemão)/genética , Rubéola (Sarampo Alemão)/virologia , Vacina contra Rubéola/genética , Vírus da Rubéola/genética , Vírus da Rubéola/patogenicidade , Federação Russa , Análise de Sequência de DNA , Células VeroRESUMO
The paper gives the results of a comparative analysis of the detection of influenza viruses in clinical samples, by using multiplex real-time polymerase chain reaction (RT-PCR) and by virus isolation in MDCK cell cultures. The investigation employed 267 nasopharyngeal swab specimens obtained from patients with influenza symptoms during two epidemic seasons (2008-2009 and 2009-2010). Influenza viruses were found in 104 samples (48 with influenza A virus (IAV) and 56 with influenza B virus (IBV)) by multiplex RT-RCR and in 84 samples (35 with IAV and 49 with IBV) by a cultural technique. The results of detection of influenza viruses by the two methods showed 89.4% agreement. The diagnostic sensitivity of multiplex RT-PCR testing a panel of the clinical samples in question was estimated to be 94.3% for IAV and 95.9% for IBV. The diagnostic sensitivity of multiplex RT-PCR in virus detection was demonstrated to be not only highly competitive with virus isolation, but also superior to the latter.
Assuntos
Vírus da Influenza A/genética , Vírus da Influenza B/genética , Influenza Humana/diagnóstico , Animais , Técnicas de Cultura de Células , Linhagem Celular , Diagnóstico Diferencial , Cães , Feminino , Humanos , Vírus da Influenza A/isolamento & purificação , Vírus da Influenza B/isolamento & purificação , Influenza Humana/virologia , Masculino , Nasofaringe/virologia , Reação em Cadeia da Polimerase em Tempo Real , Sensibilidade e EspecificidadeRESUMO
AIM: Study of morphologic and karyologic characteristics of 5 russian human diploid cell lines (HDC). MATERIALS AND METHODS: 5 HDC lines and HDC strain MRC-5 were studied; RK-13 and Vero continuous cell lines were used; viruses: rubella (RA27/3), measles (L-16), epidemic parotitis (L-3). Cytogenetic analysis of HDC was performed by using DAPI differential staining method. RESULTS: M-29 line has characteristics that are similar to those of MRC-5 diploid cell strain. M-29 cell culture is not contaminated with foreign viruses, mycoplasmata, does not have oncogenic potency. CONCLUSION: M-29 line has high virus-productive properties for accumulation of measles, rubella and epidemic parotitis vaccine viruses and may be recommended as a substrate for the production of antiviral vaccines.
Assuntos
Linhagem Celular , Morbillivirus/isolamento & purificação , Vírus da Caxumba/isolamento & purificação , Vacinas Virais , Cultura de Vírus/métodos , Diploide , Humanos , Sarampo/prevenção & controle , Morbillivirus/crescimento & desenvolvimento , Caxumba/prevenção & controle , Vírus da Caxumba/crescimento & desenvolvimentoRESUMO
AIM: To develop method of rubella virus titer measurement in virus-containing fluid using real-time PCR (RT-PCR) with fluorescent detection. MATERIALS AND METHODS: Measurement of infectious titer of rubella virus (Wistar RA 27/3 strain) cultivated on Vero cells was performed simultaneously by RT-PCR and cytopathic effect assay (CEA) on PK-13 cell culture and then results obtained by each method were compared. RESULTS: Time interval after inoculation, in which difference between virus titer measured by both methods did not exceed 0.3 1gTCD50/ml (value acceptable by WHO), was 2 - 7 days. Pearson correlation coefficient between two values for the mentioned interval was close to 1, which point to good agreement of results. In control sample--international vaccine standard of rubella virus--difference in virus titer determined by RT-PCR and CEA was within 0.2 1gTCD50/ml that lower than value acceptable by WHO. CONCLUSION: Method for measurement of rubella virus titer in virus-containing fluid using RT-PCR was developed, which characterized by high specificity, sensitivity, standard performing, shorter time needed for procedure compared with classic methods and, at the same time, high correlation of its results with results obtained by the latter methods during defined time interval.