Glycan masking of hemagglutinin for adenovirus vector and recombinant protein immunizations elicits broadly neutralizing antibodies against H5N1 avian influenza viruses

PLoS One. 2014 Mar 26;9(3):e92822. doi: 10.1371/journal.pone.0092822. eCollection 2014.

Abstract

The highly pathogenic avian influenza (HPAI) H5N1 virus, a known trigger of diseases in poultry and humans, is perceived as a serious threat to public health. There is a clear need for a broadly protective H5N1 vaccine or vaccines for inducing neutralizing antibodies against multiple clades/subclades. We constructed single, double, and triple mutants of glycan-masked hemagglutiinin (HA) antigens at residues 83, 127 and 138 (i.e., g83, g127, g138, g83+g127, g127+g138, g83+g138 and g83+g127+g138), and then obtained their corresponding HA-expressing adenovirus vectors and recombinant HA proteins using a prime-boost immunization strategy. Our results indicate that the glycan-masked g127+g138 double mutant induced more potent HA-inhibition, virus neutralization antibodies, cross-clade protection against heterologous H5N1 clades, correlated with the enhanced bindings to the receptor binding sites and the highly conserved stem region of HA. The immune refocusing stem-specific antibodies elicited by the glycan-masked H5HA g127+g138 and g83+g127+g138 mutants overlapped with broadly neutralizing epitopes of the CR6261 monoclonal antibody that neutralizes most group 1 subtypes. These findings may provide useful information in the development of a broadly protective H5N1 influenza vaccine.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenoviridae / metabolism*
  • Animals
  • Antibodies, Neutralizing / immunology*
  • Antibodies, Viral / immunology
  • Antigens, Viral / immunology
  • Cross Protection / immunology
  • Female
  • Genetic Vectors
  • Hemagglutination Inhibition Tests
  • Hemagglutinins / immunology*
  • Immunization*
  • Immunoglobulin G / immunology
  • Influenza A Virus, H5N1 Subtype / immunology*
  • Influenza Vaccines / immunology
  • Inhibitory Concentration 50
  • Mice, Inbred BALB C
  • Models, Molecular
  • Mutant Proteins / metabolism
  • Orthomyxoviridae Infections / immunology
  • Orthomyxoviridae Infections / virology
  • Polysaccharides / immunology*
  • Recombinant Proteins / immunology*
  • Species Specificity

Substances

  • Antibodies, Neutralizing
  • Antibodies, Viral
  • Antigens, Viral
  • Hemagglutinins
  • Immunoglobulin G
  • Influenza Vaccines
  • Mutant Proteins
  • Polysaccharides
  • Recombinant Proteins

Grants and funding

This study was supported by the National Science Council (NSC-102-2321-B-007-002, NSC-103-2321-B-007-006) and the Veterans General Hospitals University Systems of Taiwan Joint Research Program (VGHUST103-G6-1-2), Taiwan. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.