tetano
Editor, Senior Moderator
J Clin Virol. 2012 Aug 22. [Epub ahead of print]
Molecular evolution of HA gene of the influenza A H1N1 pdm09 strain during the consecutive seasons 2009-2011 in Hangzhou, China: Several immune-escape variants without positively selected sites.
Li J, Shao TJ, Yu XF, Pan JC, Pu XY, Wang HQ, Kou Y.
Source
Microbiology Laboratory, Hangzhou Center for Disease Control and Prevention, Zhejiang 310021, China.
Abstract
BACKGROUND:
Even under immune pressure, the highly active influenza A H1N1 pdm09 variants emerged again in December 2010. Did the variability lead to poor vaccine effectiveness?
OBJECTIVES:
To study the genetic distance and antigenic drift of the influenza A H1N1 pdm09 strains based on the sequence analysis of HA virus gene segments during consecutive seasons 2009-2011 in Hangzhou, China.
STUDY DESIGN:
39 Clinical samples from influenza-like-illness patients with culture-confirmed influenza A H1N1 pdm09 infections were collected over seasons in routine influenza surveillance. The HA gene was amplified and sequenced. A perspective analysis of genetic distance, antigenic drift and positively selected sites were conducted.
RESULTS:
Analyses of human influenza A H1N1 pdm09 strains isolated in Hangzhou revealed that during the seasons 2009-2011, the antigenic drift had occurred, away from the northern hemisphere 2010/2011 influenza vaccine strain A/California/07/2009. The 2010/2011 viruses cluster in two main branches with a significant genetic distance, characterized by either S202T and S468N, or K180T/I, V216A, P288S, I312V and I389F. Interestingly, the epitopes corresponding to the immune-escape characteristic have altered much, but none of the amino acid substitutions in 2010/2011 variants were positively selected.
CONCLUSIONS:
The results of genetic surveillance in this study might account for frequent outbreaks of the influenza A H1N1 pdm09 strains since December 2010 and the disappearance after three months circulation. It facilitates early detection of antigenic sites for the virus to escape immunological restraint in 2010/2011 season. Continuous monitoring of antigenic changes is recommended.
Copyright ? 2012 Elsevier B.V. All rights reserved.
PMID:
22921413
[PubMed - as supplied by publisher]
http://www.ncbi.nlm.nih.gov/pubmed/22921413
Molecular evolution of HA gene of the influenza A H1N1 pdm09 strain during the consecutive seasons 2009-2011 in Hangzhou, China: Several immune-escape variants without positively selected sites.
Li J, Shao TJ, Yu XF, Pan JC, Pu XY, Wang HQ, Kou Y.
Source
Microbiology Laboratory, Hangzhou Center for Disease Control and Prevention, Zhejiang 310021, China.
Abstract
BACKGROUND:
Even under immune pressure, the highly active influenza A H1N1 pdm09 variants emerged again in December 2010. Did the variability lead to poor vaccine effectiveness?
OBJECTIVES:
To study the genetic distance and antigenic drift of the influenza A H1N1 pdm09 strains based on the sequence analysis of HA virus gene segments during consecutive seasons 2009-2011 in Hangzhou, China.
STUDY DESIGN:
39 Clinical samples from influenza-like-illness patients with culture-confirmed influenza A H1N1 pdm09 infections were collected over seasons in routine influenza surveillance. The HA gene was amplified and sequenced. A perspective analysis of genetic distance, antigenic drift and positively selected sites were conducted.
RESULTS:
Analyses of human influenza A H1N1 pdm09 strains isolated in Hangzhou revealed that during the seasons 2009-2011, the antigenic drift had occurred, away from the northern hemisphere 2010/2011 influenza vaccine strain A/California/07/2009. The 2010/2011 viruses cluster in two main branches with a significant genetic distance, characterized by either S202T and S468N, or K180T/I, V216A, P288S, I312V and I389F. Interestingly, the epitopes corresponding to the immune-escape characteristic have altered much, but none of the amino acid substitutions in 2010/2011 variants were positively selected.
CONCLUSIONS:
The results of genetic surveillance in this study might account for frequent outbreaks of the influenza A H1N1 pdm09 strains since December 2010 and the disappearance after three months circulation. It facilitates early detection of antigenic sites for the virus to escape immunological restraint in 2010/2011 season. Continuous monitoring of antigenic changes is recommended.
Copyright ? 2012 Elsevier B.V. All rights reserved.
PMID:
22921413
[PubMed - as supplied by publisher]
http://www.ncbi.nlm.nih.gov/pubmed/22921413