Vaccine and oncogenic strains of gallid herpesvirus 2 contain specific subtype variations in the 5' region of the latency-associated transcript that evolve in vitro and in vivo.
Arch Virol
; 160(1): 161-71, 2015 Jan.
Article
em En
| MEDLINE
| ID: mdl-25298182
ABSTRACT
Gallid herpesvirus 2 (GaHV-2) is the alphaherpesvirus responsible for Marek's disease (MD), a T-cell lymphoma of chickens. The virulence of the GaHV-2 field strain is steadily increasing, but MD is still controlled by the CVI988/Rispens vaccine. We tried to determine distinguishing traits of the CVI988/Rispens vaccine by focusing on the 5' end region of the latency-associated transcript (5'LAT). It includes a variable number of 60-bp tandem repeats depending on the GaHV-2 strain. By analyzing six batches of vaccine, we showed that CVI988/Rispens consisted of a population of 5'LAT molecular subtypes, all with deletions and lacking 60-bp tandem repeat motifs, with two major subtypes that probably constitute CVI988/Rispens markers. Serial passages in cell culture led to a substantial change in the frequency of CVI988/Rispens 5'LAT subtypes, with non-deleted subtypes harboring up to four 60-bp repeats emerging during the last few passages. Dynamic changes in the distribution of 5'LAT-deleted subtypes were also detected after infection of chickens. By contrast, the 5'LAT region of the oncogenic clonal RB-1B strain, which was investigated at every step from the isolation of the clonal bacmid RB-1B DNA to the isolation of the ovarian lymphoma cell line, consisted of non-deleted 5'LAT subtypes harboring at least two 60-bp repeats. Thus, vaccine and oncogenic GaHV-2 strains consist of specific populations of viral genomes that are constantly evolving in vivo and in vitro and providing potential markers for epidemiological surveys.
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1
Base de dados:
MEDLINE
Assunto principal:
Variação Genética
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Proteínas Virais
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Vacinas Virais
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Regulação Viral da Expressão Gênica
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Doença de Marek
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Herpesvirus Galináceo 2
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Evolução Molecular
Tipo de estudo:
Risk_factors_studies
Limite:
Animals
Idioma:
En
Ano de publicação:
2015
Tipo de documento:
Article