H5-type influenza virus hemagglutinin is functionally recognized by the natural killer-activating receptor NKp44

J Virol. 2008 Feb;82(4):2028-32. doi: 10.1128/JVI.02065-07. Epub 2007 Dec 12.


Antiviral immune defenses involve natural killer (NK) cells. We previously showed that the NK-activating receptor NKp44 is involved in the functional recognition of H1-type influenza virus strains by NK cells. In the present study, we investigated the interaction of NKp44 and the hemagglutinin of a primary influenza virus H5N1 isolate. Here we show that recombinant NKp44 recognizes H5-expressing cells and specifically interacts with soluble H5 hemagglutinin. H5-pseudotyped lentiviral particles bind to NK cells expressing NKp44. Following interaction with target cells expressing H5, pseudotyped lentiviral particles, or membrane-associated H5, NK cells show NKp44-mediated induced activity. These findings indicate that NKp44-H5 interactions induce functional NK activation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Line
  • Hemagglutinin Glycoproteins, Influenza Virus / genetics
  • Hemagglutinin Glycoproteins, Influenza Virus / metabolism*
  • Humans
  • Influenza A Virus, H5N1 Subtype / immunology*
  • Killer Cells, Natural / immunology*
  • Killer Cells, Natural / virology
  • Natural Cytotoxicity Triggering Receptor 2
  • Receptors, Immunologic / genetics
  • Receptors, Immunologic / metabolism*
  • Recombinant Proteins / genetics
  • Recombinant Proteins / metabolism


  • Hemagglutinin Glycoproteins, Influenza Virus
  • NCR2 protein, human
  • Natural Cytotoxicity Triggering Receptor 2
  • Receptors, Immunologic
  • Recombinant Proteins
  • hemagglutinin, avian influenza A virus