tetano
Editor, Senior Moderator
J Virol. 2017 Jan 4. pii: JVI.01073-16. doi: 10.1128/JVI.01073-16. [Epub ahead of print]
[h=1]Generation of a genetically stable high-fidelity influenza vaccine strain.[/h] Naito T[SUP]1[/SUP], Mori K[SUP]2,[/SUP][SUP]3,[/SUP][SUP]4[/SUP], Ushirogawa H[SUP]5[/SUP], Takizawa N[SUP]2[/SUP], Nobusawa E[SUP]6[/SUP], Odagiri T[SUP]6[/SUP], Tashiro M[SUP]6[/SUP], Ohniwa RL[SUP]3,[/SUP][SUP]7[/SUP], Nagata K[SUP]8[/SUP], Saito M[SUP]5[/SUP].
[h=3]Author information[/h]
[h=3]Abstract[/h] Vaccination is considered the most effective preventive means for influenza control. The development of a master virus with high growth and genetic stability, which may be used for the preparation of vaccine viruses by gene reassortment, is crucial for the enhancement of vaccine performance and efficiency of production. Here, we describe the generation of a high-fidelity and high-growth influenza vaccine master virus strain with a single V43I amino acid change in the PB1 polymerase of the high-growth PR8 master virus. The PB1-V43I mutation was introduced to increase replication fidelity, in order to design an H1N1 vaccine strain with low error rate. The PR8-PB1-V43I virus exhibited good replication compared with the parent PR8 virus. In order to compare the efficiency of egg-adaptation and occurrence of gene mutations leading to antigenic alterations, we constructed genetic 6:2 genetic reassortant viruses between A(H1N1)pdm09 and the PR8-PB1-V43I viruses; HA and NA were from the A(H1N1)pdm09 virus and the other genes from the PR8 virus. Mutations responsible for egg-adaptation mutations occurred in the HA of the PB1-V43I reassortant virus during serial egg passages; however, in contrast, antigenic mutations were introduced into the HA gene of the 6:2 reassortant virus possessing the wild-type PB1. This study shows that the mutant PR8 virus possessing the PB1 with V43I substitution may be utilized as a master virus for the generation of high-growth vaccine viruses with high polymerase fidelity, low error rates of gene replication, and reduced antigenic diversity during viral propagation in eggs, for vaccine production.
[h=4]IMPORTANCE:[/h] Vaccination represents the most effective prophylactic option against influenza. The threat of emergence of influenza pandemics necessitates the ability to generate vaccine viruses rapidly. However, as the influenza virus exhibits a high mutation rate, vaccines must be updated to ensure a good match of the HA and NA antigens between vaccine and the circulating strain. Here, we generated a genetically stable master virus of A/Puerto Rico/8/1934(H1N1)-backbone encoding an engineered high-fidelity viral polymerase. Importantly, following the application of the high-fidelity PR8 backbone, no mutation resulting in antigenic change was introduced into the HA gene during propagation of the A(H1N1)pdm09 candidate vaccine virus. The low error rate of the present vaccine virus should decrease the risk of generation of mutant viruses with increased virulence. Therefore, our findings are expected to be useful for the development of pre-pandemic vaccines and live attenuated vaccines with higher safety relative to present candidate vaccines.
Copyright ? 2017 American Society for Microbiology.
PMID: 28053101 DOI: 10.1128/JVI.01073-16
[PubMed - as supplied by publisher]
[h=1]Generation of a genetically stable high-fidelity influenza vaccine strain.[/h] Naito T[SUP]1[/SUP], Mori K[SUP]2,[/SUP][SUP]3,[/SUP][SUP]4[/SUP], Ushirogawa H[SUP]5[/SUP], Takizawa N[SUP]2[/SUP], Nobusawa E[SUP]6[/SUP], Odagiri T[SUP]6[/SUP], Tashiro M[SUP]6[/SUP], Ohniwa RL[SUP]3,[/SUP][SUP]7[/SUP], Nagata K[SUP]8[/SUP], Saito M[SUP]5[/SUP].
[h=3]Author information[/h]
[h=3]Abstract[/h] Vaccination is considered the most effective preventive means for influenza control. The development of a master virus with high growth and genetic stability, which may be used for the preparation of vaccine viruses by gene reassortment, is crucial for the enhancement of vaccine performance and efficiency of production. Here, we describe the generation of a high-fidelity and high-growth influenza vaccine master virus strain with a single V43I amino acid change in the PB1 polymerase of the high-growth PR8 master virus. The PB1-V43I mutation was introduced to increase replication fidelity, in order to design an H1N1 vaccine strain with low error rate. The PR8-PB1-V43I virus exhibited good replication compared with the parent PR8 virus. In order to compare the efficiency of egg-adaptation and occurrence of gene mutations leading to antigenic alterations, we constructed genetic 6:2 genetic reassortant viruses between A(H1N1)pdm09 and the PR8-PB1-V43I viruses; HA and NA were from the A(H1N1)pdm09 virus and the other genes from the PR8 virus. Mutations responsible for egg-adaptation mutations occurred in the HA of the PB1-V43I reassortant virus during serial egg passages; however, in contrast, antigenic mutations were introduced into the HA gene of the 6:2 reassortant virus possessing the wild-type PB1. This study shows that the mutant PR8 virus possessing the PB1 with V43I substitution may be utilized as a master virus for the generation of high-growth vaccine viruses with high polymerase fidelity, low error rates of gene replication, and reduced antigenic diversity during viral propagation in eggs, for vaccine production.
[h=4]IMPORTANCE:[/h] Vaccination represents the most effective prophylactic option against influenza. The threat of emergence of influenza pandemics necessitates the ability to generate vaccine viruses rapidly. However, as the influenza virus exhibits a high mutation rate, vaccines must be updated to ensure a good match of the HA and NA antigens between vaccine and the circulating strain. Here, we generated a genetically stable master virus of A/Puerto Rico/8/1934(H1N1)-backbone encoding an engineered high-fidelity viral polymerase. Importantly, following the application of the high-fidelity PR8 backbone, no mutation resulting in antigenic change was introduced into the HA gene during propagation of the A(H1N1)pdm09 candidate vaccine virus. The low error rate of the present vaccine virus should decrease the risk of generation of mutant viruses with increased virulence. Therefore, our findings are expected to be useful for the development of pre-pandemic vaccines and live attenuated vaccines with higher safety relative to present candidate vaccines.
Copyright ? 2017 American Society for Microbiology.
PMID: 28053101 DOI: 10.1128/JVI.01073-16
[PubMed - as supplied by publisher]