甲型H1N1流感病毒神经氨酸酶基因遗传进化分析

Genetic Evolution of Neuraminidase Gene of Influenza A/H1N1 Virus

【目的】了解季节性H1N1流感病毒与2009年新型H1N1流感病毒神经氨酸酶(NA)基因的遗传进化关系,探讨甲型H1N1流感病毒的遗传变异规律。【方法】分别从2006年和2009年流感病人标本中分离并鉴定出季节性HIN1流感病毒和新型H1N1流感病毒,用RT-PCR技术扩增了病毒NA基因全序列,并对其分子进化和重要功能位点的遗传变异进行了分析。【结果】2009年新型H1N1流感病毒与2006年季节性HIN1流感病毒比较,NA基因的同源性较低(77.9%～78.8%),与世界各地不同年代代表株及WHO推荐的1979～2010年季节性流感疫苗株比较,NA基因的同源性也较低(78.1%～79.3%),但与WHO推荐的2009年新型H1N1流感疫苗株比较同源性则高达99%以上;系统进化分析结果表明,2009年新型H1N1流感病毒NA基因与欧亚猪流感病毒株A/swine/Belgium/1/1983的亲缘关系最近;并发现自2005年以来季节性H1N1流感病毒NA基因的某些抗原位点和神经氨酸酶活性位点已发生了变异。【结论】2009年新型H1N1流感病毒NA基因可能来源于欧亚猪流感病毒;接种季节性流感疫苗不能对本次流行的新型流感产生有效的免疫保护作用;季节性H1N1流感病毒在流行过程中NA基因已发生了一定的变异,有必要持续跟踪和监测病毒的变异情况。

【Objective】 This study was designed to investigate the genetic evolution of the neuraminidase （NA） gene of seasonal A/H1N1 and 2009 novel A/H1N1 influenza 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 lineage, 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 lineage 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.