Broader neutralizing antibodies against H5N1 viruses using prime-boost immunization of hyperglycosylated hemagglutinin DNA and virus-like particles.
BACKGROUND
Highly pathogenic avian influenza (HPAI) H5N1 viruses and their transmission capability from birds to humans have raised global concerns about a potential human pandemic. The inherent nature of antigenic changes in influenza viruses has not been sufficiently taken into account in immunogen designs for broadly protective HPAI H5N1 vaccines.


METHODS
We designed a hyperglycosylated HA vaccine using N-linked glycan masking on highly variable sequences in the HA1 globular head. Immunization of these hyperglycosylated HA DNA vaccines followed by a flagellin-containing virus-like particle booster in mice was conducted to evaluate neutralizing antibody responses against various clades of HPAI H5N1 viruses.


RESULTS
We introduced nine N-X-S/T motifs in five HA1 regions: 83NNT, 86NNT, 94NFT, 127NSS, 138NRT, 156NTT, 161NRS, 182NDT, and 252NAT according to sequence alignment analyses from 163 HPAI H5N1 human isolates. Although no significant differences of anti-HA total IgG titers were found with these hyperglycosyalted HA compared to the wild-type control, the 83NNT and 127NSS mutants elicited significantly potent cross-clade neutralizing antibodies against HPAI H5N1 viruses.


CONCLUSIONS
This finding may have value in terms of novel immunogen design for developing cross-protective H5N1 vaccines.
Institute of Biotechnology, National Tsing Hua University, Hisnchu, Taiwan.
Shih-Chang
SC
Lin
Yu-Fen
YF
Lin
Pele
P
Chong
Suh-Chin
SC
Wu
D000818:Animals; D057134:Antibodies, Neutralizing / Q000276:immunology*; D004247:DNA / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006031:Glycosylation; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000276:immunology*; D006801:Humans; D053124:Influenza A Virus, H5N1 Subtype / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D014771:Virion / Q000276:immunology*
D057134:Antibodies, Neutralizing; D019267:Hemagglutinin Glycoproteins, Influenza Virus; D004247:DNA