Université de Lyon, F-69000, Lyon, France.
Virology. 2010 Sep 1;404(2):215-24. doi: 10.1016/j.virol.2010.04.030.
Among a panel of 788 clinical influenza H3N2 isolates, two isolates were characterized by an oseltamivir-resistant phenotype linked to the absence of any detectable NA activity. Here, we established that the two H3NA- isolates lack any detectable full-length NA segment, and one of these could be rescued by reverse genetics in the absence of any NA segment sequence. We found that the absence of NA segment induced a moderate growth defect of the H3NA- viruses as on cultured cells. The glycoproteins density at the surface of H3NA- virions was unchanged as compared to H3N2 virions. The HA protein as well as residues 188 and 617 of the PB1 protein were shown to be strong determinants of the ability of H3NA- viruses to grow in the absence of the NA segment. The significance of these findings about naturally occurring seven-segment influenza A viruses is discussed.
在 788 个临床分离的 H3N2 流感病毒中，有两个分离株表现出奥司他韦耐药表型，与检测不到任何 NA 活性有关。在这里，我们确定这两个 H3N-分离株缺乏任何可检测到的全长 NA 片段，其中一个可以在没有任何 NA 片段序列的情况下通过反向遗传学拯救。我们发现，NA 片段的缺失会导致 H3N-病毒在培养细胞中的生长缺陷适度增加。与 H3N2 病毒相比，H3NA-病毒的表面糖蛋白密度没有变化。HA 蛋白以及 PB1 蛋白的 188 位和 617 位残基被证明是 H3N-病毒在没有 NA 片段的情况下生长的能力的重要决定因素。这些关于自然发生的七段流感 A 病毒的发现的意义将进行讨论。
