Abstract
The miRNA-based strategy has been used to develop live attenuated influenza vaccines. In this study, the nucleoprotein (NP) genome segment of the influenza virus was inserted by different perfect miRNA-192-5p target sites, and the virus was rescued by standard reverse genetics method, so as to verify the virulence and protective efficacy of live attenuated vaccine in cells and mice. The results showed there was no significant attenuation in 192t virus with one perfect miRNA-192-5p target site, and 192t-3 virus with three perfect miRNA target sites. However, 192t-6 virus with 6 perfect miRNA target sites and 192t-9 virus with 9 perfect miRNA target sites were both significantly attenuated after infection, and their virulence were similar to that of temperature-sensitive (TS) influenza A virus (IAV) which is a temperature-sensitive live attenuated influenza vaccine. Mice were immunized with different doses of 192t-6, 192t-9, and TS IAV. Four weeks after immunization, the IgG in serum and IgA in lung homogenate were increased in the 192t-6, 192t-9, and TS IAV groups, and the numbers of IFN-γ secreting splenocytes were also increased in a dose-dependent manner. Finally, 192t-6, and 192t-9 can protect the mice against the challenge of homologous PR8 H1N1 virus and heterosubtypic H3N2 influenza virus. MiRNA targeted viruses 192t-6 and 192t-9 were significantly attenuated and showed the same virulence as TS IAV and played a role in the cross-protection.
Highlights
Influenza vaccine is the recommended approach to protect against influenza virus infection.Currently, influenza vaccines approved by the US FDA include inactivated influenza vaccine (IIV), recombinant influenza protein (RIP), and live attenuated influenza vaccine (LAIV) [1]
Influenza vaccines approved by the US FDA include inactivated influenza vaccine (IIV), recombinant influenza protein (RIP), and live attenuated influenza vaccine (LAIV) [1]
After the miRNA was transfected into A549 cells and infected by H7N9 virus, we found that inhibiting the hsa-miR-664-3p can obviously reduce H7N9 virus replication, or reduce H1N1 and H3N2 viruses replication [17], which indicated that miRNA plays an important regulatory role when the influenza virus attacks host cells
Summary
Influenza vaccine is the recommended approach to protect against influenza virus infection. Several studies found that LAIVs have good immunogenicity, and can induce humoral immunity, especially mucosal immunity and cellular immunity to provide cross-protection against influenza virus infection and might provide better protection than IIV due to influenza virus antigenic drift and shift. After the miRNA was transfected into A549 cells and infected by H7N9 virus, we found that inhibiting the hsa-miR-664-3p can obviously reduce H7N9 virus replication, or reduce H1N1 and H3N2 viruses replication [17], which indicated that miRNA plays an important regulatory role when the influenza virus attacks host cells These miRNAs were only used for regulating virus vRNA to study the virus attenuated mechanism in these researches. Our study mainly explored the different perfect miRNA-192-5p target sites which were inserted into the NP genome segment of the PR8 influenza virus, so as to study the virulence of miRNA targeted viruses, their pathogenicity on cells and animals, their immunogenicity in a mouse model, as well as the protective immunity during the homologous PR8 and heterosubtypic H3N2 viruses challenge
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
