Evolution of A(H1N1) pdm09 influenza virus masking by glycosylation

ABSTRACT

Introduction: As the pathogen that caused the first influenza virus pandemic in this century, the swine-origin A(H1N1) pdm09 influenza virus has caused continuous harm to human public health. The evolution of hemagglutinin protein glycosylation sites, including the increase in number and positional changes, is an important way for influenza viruses to escape host immune pressure. Based on the traditional influenza virus molecular monitoring, special attention should be paid to the influence of glycosylation evolution on the biological characteristics of virus antigenicity, transmission and pathogenicity. The epidemiological significance of glycosylation mutants should be analyzed as a predictive tool for early warning of new outbreaks and pandemics, as well as the design of vaccines and drug targets.

Areas covered: We review on the evolutionary characteristics of glycosylation on the HA protein of the A(H1N1)pdm09 influenza virus in the last ten years.

Expert opinion: We discuss the crucial impact of evolutionary glycosylation on the biological characteristics of the virus and the host immune responses, summarize studies revealing different roles of glycosylation play during host adaptation. Although these studies show the significance of glycosylation evolution in host-virus interaction, much remains to be discovered about the mechanism.

KEYWORDS:

• Glycosylation
• HA
• influenza
• mutation

Article highlights

• Influenza virus pandemics are unexpected events due to reassorted viral strains that spread rapidly in immunologically naïve populations, as A(H1N1)pdm09 virus is expected to circulate as a seasonal virus, the evolution of the strain must be closely monitored.

• Influenza viruses evade host immunity following infection and influenza virus vaccines need to be updated every season because the vaccine targeting at the viral HA is less effective over time.

• The evolution of HA protein glycosylation is an important strategy for virus to escape immune pressure.

• The number and location of glycosylation sites are changing and monitored data shows new antigen variants continued to appear.

• Surveillance and monitor works should be strengthened to keep up with the evolutionary glycosylation.

Acknowledgments

P.G. and T.M.R. received support from the University of Georgia. In addition, T.M.R. is supported by the Georgia Research Alliance as an Eminent Scholar.

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Author contributions

Both authors contributed to the intellectual content of the manuscript and gave final approval of the version to be published. P.G. wrote the manuscript.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Additional information

Funding

This paper was not funded.