A high-affinity CDR-grafted antibody against influenza A H5N1 viruses recognizes a conserved epitope of H5 hemagglutinin

PLoS One. 2014 Feb 18;9(2):e88777. doi: 10.1371/journal.pone.0088777. eCollection 2014.

Abstract

Highly pathogenic avian influenza (HPAI) H5N1 virus infection is still a potential threat to public health worldwide. While vaccines and antiviral drugs are currently under development, neutralizing antibodies could offer an alternative strategy to prevent and treat H5N1 virus infection. In the present study, we had developed a humanized antibody against H5N1 viruses from mouse-derived hybridoma in order to minimize its immunogenicity for potential clinical application. The humanized antibody hH5M9 was generated by transferring the mouse complementarity determining region (CDR) residues together with four key framework region (FR) residues onto the FR of the human antibody. This humanized antibody exhibited high affinity and specificity comparable to the parental mouse or chimeric counterpart with broad and strong neutralization activity against all H5N1 clades and subclades except for Egypt clades investigated. Furthermore, through epitope mapping we identified a linear epitope on the top region of hemagglutinin (HA) that was H5N1 specific and conserved. Our results for the first time reported a humanized antibody against H5N1 viruses by CDR grafting method. With the expected lower immunogenicity, this humanized antibody was expected to be more efficacious than murine or human-mouse chimeric antibodies for future application in humans.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Antibodies, Monoclonal, Humanized / chemistry
  • Antibodies, Monoclonal, Humanized / immunology*
  • Antibodies, Neutralizing / chemistry
  • Antibodies, Neutralizing / immunology
  • Complementarity Determining Regions / immunology*
  • Conserved Sequence*
  • Epitope Mapping
  • Epitopes / immunology*
  • Hemagglutinin Glycoproteins, Influenza Virus / immunology*
  • Humans
  • Influenza A Virus, H5N1 Subtype / immunology*
  • Mice
  • Models, Molecular
  • Molecular Sequence Data
  • Protein Conformation

Substances

  • Antibodies, Monoclonal, Humanized
  • Antibodies, Neutralizing
  • Complementarity Determining Regions
  • Epitopes
  • Hemagglutinin Glycoproteins, Influenza Virus

Grants and funding

This work was supported by National High Technology Research and Development Program of China (863 Program, Grant No. 2006AA 02A 252) http://www.863.gov.cn/; and National Science and Technology Major Project of the Ministry of Science and Technology of China (Grant No. 2011ZX09506-001) http://www.nmp.gov.cn/. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.