Enhancing Neuraminidase Immunogenicity of Influenza A Viruses by Rewiring RNA Packaging Signals

J Virol. 2020 Jul 30;94(16):e00742-20. doi: 10.1128/JVI.00742-20. Print 2020 Jul 30.


Humoral immune protection against influenza virus infection is mediated largely by antibodies against hemagglutinin (HA) and neuraminidase (NA), the two major glycoproteins on the virus surface. While influenza virus vaccination efforts have focused mainly on HA, NA-based immunity has been shown to reduce disease severity and provide heterologous protection. Current seasonal vaccines do not elicit strong anti-NA responses-in part due to the immunodominance of the HA protein. Here, we demonstrate that by swapping the 5' and 3' terminal packaging signals of the HA and NA genomic segments, which contain the RNA promoters, we are able to rescue influenza viruses that express more NA and less HA. Vaccination with formalin-inactivated "rewired" viruses significantly enhances the anti-NA antibody response compared to vaccination with unmodified viruses. Passive transfer of sera from mice immunized with rewired virus vaccines shows better protection against influenza virus challenge. Our results provide evidence that the immunodominance of HA stems in part from its abundance on the viral surface, and that rewiring viral packaging signals-thereby increasing the NA content on viral particles-is a viable strategy for improving the immunogenicity of NA in an influenza virus vaccine.IMPORTANCE Influenza virus infections are a major source of morbidity and mortality worldwide. Increasing evidence highlights neuraminidase as a potential vaccination target. This report demonstrates the efficacy of rewiring influenza virus packaging signals for creating vaccines with more neuraminidase content which provide better neuraminidase (NA)-based protection.

Keywords: immunodominance; influenza; neuraminidase; packaging signal; vaccine.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antibodies, Viral / immunology
  • Cross Protection
  • Cross Reactions
  • Female
  • Gene Expression / genetics
  • Gene Expression Regulation, Viral / genetics
  • HEK293 Cells
  • Hemagglutinin Glycoproteins, Influenza Virus / genetics
  • Hemagglutinins / immunology
  • Humans
  • Influenza A Virus, H1N1 Subtype / genetics
  • Influenza A Virus, H3N2 Subtype / genetics
  • Influenza A Virus, H5N1 Subtype / genetics
  • Influenza A virus / genetics*
  • Influenza Vaccines / immunology
  • Influenza, Human / virology
  • Mice
  • Mice, Inbred BALB C
  • Neuraminidase / genetics*
  • Neuraminidase / immunology*
  • Orthomyxoviridae Infections / virology
  • RNA / genetics
  • Vaccination / methods


  • Antibodies, Viral
  • Hemagglutinin Glycoproteins, Influenza Virus
  • Hemagglutinins
  • Influenza Vaccines
  • RNA
  • Neuraminidase