Superior neutralizing antibody response and protection in mice vaccinated with heterologous DNA prime and virus like particle boost against HPAI H5N1 virus

PLoS One. 2011 Jan 28;6(1):e16563. doi: 10.1371/journal.pone.0016563.


Background: Although DNA plasmid and virus-like particle (VLP) vaccines have been individually tested against highly pathogenic avian influenza (HPAI) H5N1 viruses, the combination of both vaccines into a heterologous prime-boost strategy against HPAI H5N1 viruses has not been reported before.

Methodology/principal findings: We constructed DNA plasmid encoding H5HA (A/Shenzhen/406H/06, subclade 2.3.4) and generated VLP expressing the same H5HA and N1NA. We then compared neutralizing antibody responses and immune protection elicited with heterologous DNA-VLP, homologous DNA-DNA and VLP-VLP prime-boost strategies against HPAI H5N1 viruses in mice. We demonstrate that DNA-VLP elicits the highest neutralizing antibody titers among the three prime-boost strategies, whereas DNA-DNA elicits higher neutralizing antibody titers than VLP-VLP. We show that although all three prime-boost strategies protect mice from death caused by 10 MLD(50) of homologous and heterologous H5N1 challenge, only DNA-VLP and DNA-DNA protect mice from infection as manifested by no weight loss and no lung pathology. In addition, we show that although DNA-VLP and DNA-DNA protect mice from death caused by 1,000 MLD(50) of homologous H5N1 challenge, only DNA-VLP protects mice from infection. Moreover, we show that after 1,000 MLD(50) of heterologous H5N1 challenge, while all mice in PBS, VLP-VLP and DNA-DNA died, 3 of 6 mice in DNA-VLP actually survived. Finally, we show that DNA-VLP completely protects mice from infection after 1,000 MLD(50) of homologous H5N1 challenge even when the challenge was administrated at 60 days post the boost.

Conclusions/significance: These results provide strong support for clinical evaluation of heterologous DNA-VLP prime-boost strategy as a public health intervention against a possible H5N1 pandemic.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antibodies, Neutralizing / biosynthesis*
  • Influenza A Virus, H5N1 Subtype / immunology*
  • Influenza Vaccines / immunology*
  • Mice
  • Orthomyxoviridae Infections / prevention & control
  • Orthomyxoviridae Infections / therapy
  • Treatment Outcome
  • Vaccination
  • Vaccines, DNA / administration & dosage
  • Vaccines, DNA / immunology*
  • Vaccines, Virus-Like Particle / administration & dosage
  • Vaccines, Virus-Like Particle / immunology*


  • Antibodies, Neutralizing
  • Influenza Vaccines
  • Vaccines, DNA
  • Vaccines, Virus-Like Particle