Molecular Biology

, Volume 52, Issue 4, pp 556–569 | Cite as

Mutations in Hemagglutinin and Polymerase Alter the Virulence of Pandemic A(H1N1) Influenza Virus

  • A. S. Gambaryan
  • N. F. Lomakina
  • E. Y. Boravleva
  • L. V. Mochalova
  • G. K. Sadykova
  • A. G. Prilipov
  • T. Y. Matrosovich
  • M. N. Matrosovich
Molecular Cell Biology


To study the pathogenicity factors of the pandemic A(H1N1) influenza virus, a number of mutant variants of the A/Hamburg/5/2009 (H1N1)pdm09 strain were obtained through passage in chicken embryos, mouse lungs, and MDCK cell culture. After 17 lung-to-lung passages of the A/Hamburg/5/2009 in mice, the minimum lethal dose of the derived variant decreased by five orders of magnitude compared to that of the parental virus. This variant differed from the original virus by nine amino acid residues in the following viral proteins: hemagglutinin (HA), neuraminidase (NA), and components of the polymerase complex. Additional passaging of the intermediate variants and cloning made it possible to obtain pairs of strains that differed by a single amino acid substitution. Comparative analysis of replicative activity, receptor specificity, and virulence of these variants revealed two mechanisms responsible for increased pathogenicity of the virus for mice. Thus, (1) substitutions in HA (Asp225Gly or Gln226Arg) and compensatory mutation decreasing the charge of HA (Lys123Asn, Lys157Asn, Gly158Glu, Asn159Asp, or Lys212Met) altered viral receptor-binding specificity and restored the functional balance between HA and NA; (2) Phe35Leu substitution in the PA protein increased viral polymerase activity.


pandemic A(H1N1) influenza virus pathogenicity factors 


aa residue

amino acid residue


chicken embryos


hemagglutinin (the numbering of amino acids corresponds to H3 HA)


50% mouse infectious dose


50% mouse lethal dose


matrix protein M1


Madin-Darby canine kidney cells






nonstructural protein


50% tissue culture infectious dose


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Copyright information

© Pleiades Publishing, Inc. 2018

Authors and Affiliations

  • A. S. Gambaryan
    • 1
  • N. F. Lomakina
    • 1
    • 2
  • E. Y. Boravleva
    • 1
  • L. V. Mochalova
    • 3
  • G. K. Sadykova
    • 2
  • A. G. Prilipov
    • 2
  • T. Y. Matrosovich
    • 4
  • M. N. Matrosovich
    • 4
  1. 1.Chumakov Federal Scientific Center for Research and Development of Immune-and-Biological ProductsRussian Academy of SciencesMoscowRussia
  2. 2.Gamaleya Scientific Research Institute of Epidemiology and MicrobiologyMinistry of Health of the Russian FederationMoscowRussia
  3. 3.All-Russia Institute for Scientific and Technical Information (VINITI)Russian Academy of SciencesMoscowRussia
  4. 4.Institute of VirologyPhilipps UniversityMarburgGermany

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