Genetic Evolution of Neuraminidase Gene of Influenza A/H1N1 Virus / 中山大学学报(医学科学版)

ABSTRACT

[Objective]This study was designed to investigate the genetic evolution of the neuraminidase(NA)gene of seasonal A/H1N1 and 2009 novel A/H1N1 inflilenza virus,and discuss the genetic variation of influenza A virus.[Methods]The virus strains were separately isolated from the clinical samples collected in 2006 and 2009,and then identified as seasonal A/H1N1 and novel A/H1N1.The full length of the NA gene of these strains was amplified by RT-PCR.Then the genetic evolution and mutations of important functional sites were analyzed.[Results]The homology of NA gene between the 2009 novel A/H1N1 isolates and 2006 seasonal A/H1N1 isolates was low(77.9%～78.8%),so was the homology of NA gene between the 2009 novel A/H1N1 isolates and representative strains of different periods and 1979-2001 WHO recommended vaccine strains(78.1%～79.3%).But compared with the WHO recommended vaccine strains of 2009 novel A/H1N1,the homology reached more than 99%.The genetic evolution analysis revealed that NA gene of 2009 novel A/H1N1 had the closest genetic relationship with the swine influenza A virus(A/swine/Belgium/1/1983)from Eurasian Iineage,and some of the antigenic sites and neuraminidase active sites of NA gene of seasonal A/H1N1 were mutated after 2005.[Conclusion]The NA gene of 2009 novel A/H1N1 may originate from Eurasian Iineage of swine influenza virus.The variation of NA gene of seasonal A/H1N1 has occurred in a certain degree.Hence,it is very necessary to continuously monitor the variant of influenza A virus.