Melidou Angeliki, Exindari Maria, Gioula Georgia, Chatzidimitriou Dimitris, Pierroutsakos Yiannis, Diza-Mataftsi Eudoxia
National Influenza Centre for Northern Greece, B Laboratory of Microbiology, School of Medicine, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece.
Virus Res. 2009 Nov;145(2):220-6. doi: 10.1016/j.virusres.2009.07.006. Epub 2009 Jul 15.
Influenza A viruses are characterized by a unique genome structure, causing genetic instability, especially to the genes of haemagglutinin and neuraminidase. The objectives of this research was molecular and phylogenetic analysis of influenza A(H3N2) strains that circulated in Northern Greece since 2004, particularly the identification of sequence variations and the comparison of circulating viruses with vaccine strains. Since 2004 in Northern Greece, a total of 216 clinical samples were positive for influenza virus infections, of which 83 (38.4%) were attributed to influenza A(H3N2). Molecular analysis of the HA genes of 23 isolates showed that all circulating strains had variations at antigenic sites. Receptor binding sites were conserved in 2004-2005 and 2005-2006 strains whereas a variation was observed in all 2006-2007 strains (H195Y). Furthermore, alternative amino acids for sialic acid receptor binding sites were observed in most of the 2004-2006 isolates. Some amino acid substitutions were also observed at the neuraminidase sequences, which however had no effect on the antigenicity of the viruses. Phylogenetic analysis of each year's circulating strains revealed a relatively low match with the vaccine strains A/Fujian/411/02 and A/California/7/04 for 2004-2005 and 2005-2006, respectively, whereas most 2006-2007 isolates match with the vaccine strain, A/Wisconsin/67/05. This year, unique variations were observed at antigenic and glycosylation sites of A/Serres/77/07-like stains. Constant surveillance of yearly variations is of great importance, so that vaccine strains can be evaluated.
甲型流感病毒具有独特的基因组结构，导致基因不稳定，尤其是血凝素和神经氨酸酶基因。本研究的目的是对2004年以来在希腊北部流行的甲型（H3N2）流感病毒株进行分子和系统发育分析，特别是鉴定序列变异，并将流行病毒与疫苗株进行比较。自2004年以来，在希腊北部，共有216份临床样本的流感病毒感染呈阳性，其中83份（38.4%）归因于甲型（H3N2）流感。对23株分离株的血凝素基因进行分子分析表明，所有流行株在抗原位点均有变异。2004 - 2005年和2005 - 2006年的毒株中受体结合位点保守，而在所有2006 - 2007年的毒株中观察到变异（H195Y）。此外，在2004 - 2006年的大多数分离株中还观察到唾液酸受体结合位点的替代氨基酸。在神经氨酸酶序列中也观察到一些氨基酸替代，但这些对病毒的抗原性没有影响。对每年流行株的系统发育分析显示，2004 - 2005年和2005 - 2006年的毒株分别与疫苗株A/福建/411/02和A/加利福尼亚/7/04的匹配度相对较低，而2006 - 2007年的大多数分离株与疫苗株A/威斯康星/67/05匹配。今年，在A/塞雷斯/77/07样毒株的抗原和糖基化位点观察到独特变异。持续监测每年的变异非常重要，以便对疫苗株进行评估。
