Abstract
Pandemic H1N1 2009 (A[H1N1]pdm09) variants associated with oseltamivir resistance have emerged with a histidine-to-tyrosine substitution in the neuraminidase(NA) at position 274 (H274Y). To determine whether the H274Y variant has increased virulence potential, A(H1N1)pdm09 virus, with or without the H274Y mutation, was adapted by serial lung-to-lung passages in mice. The mouse-adapted H274Y (maCA04H274Y) variants showed increased growth properties and virulence in vitro and in vivo while maintaining high NA inhibitor resistance. Interestingly, most maCA04H274Y and maCA04 viruses acquired common mutations in HA (S183P and D222G) and NP (D101G), while only maCA04H274Y viruses had consensus additional K153E mutation in the HA gene, suggesting a potential association with the H274Y substitution. Collectively, our findings highlight the potential emergence of A(H1N1)pdm09 drug-resistant variants with increased virulence and the need for rapid development of novel antiviral drugs.
Submitted
05/15/2013
Revised
07/24/2013
Accepted
07/29/2013
Disclosure of Potential Conflicts of Interest
No potential conflicts of interest were disclosed.
Acknowledgments
This work was supported by a grant from the Korea Healthcare Technology R&D Project (A103001) by the Ministry of Health and Welfare, Republic of Korea. We appreciate David Galloway for editorial assistance.