B型流感病毒系间重配进化方式对其生长特性的影响

The Effect of Influenza Type B Inter-lineage Reassortment on the Growth Characteristics of Influenza

研究系间重配进化方式对B型流感病毒生长特性的影响。挑选2013-2015年中国分离的B型流感病毒野生型及系间重配代表毒株并传代扩增。以相同量的病毒感染细胞,检测不同时间点的TCID50值,测定生长曲线;进一步对病毒神经氨酸酶动力学常数（Km值）进行检测,分析神经氨酸酶活性。病毒生长曲线显示2013年和2014年病毒在感染后48h达滴度高峰,维持至72h后滴度逐渐下降;2015年病毒滴度则在24h达到高峰。2013年系间重配株B/福建同安/1565/2013与野生型病毒相当,而2013-2015年的其他系间重配病毒的生长曲线的峰值均不及同期的野生型病毒。通过神经氨酸酶活性实验得到病毒的Km值,显示系间重配病毒中B/福建同安/1565/2013NA蛋白的亲和力最高。2014年和2015年系间重配病毒的NA亲和力低于同期的野生型病毒。2014-2015年病毒检测结果显示,神经氨酸酶亲和力较强则生长特性较好,2013年病毒的神经氨酸酶活性与生长特性表现不一致。表面蛋白基因交换造成的系间重配毒株其神经氨酸酶活性与生长特性表现并不一致,提示2013-2015年,病毒的内部蛋白影响了病毒的生长特性,有待进一步研究。

This study aims to research the effect of inter-lineage reassortment of type B influenza virus on its biological characteristics.The representative strains isolated in 2013-2015were selected,which included wild type viruses and inter-lineage reassortment viruses.We tested the growth curve of each virus based on the value of TCID50 at different time point.And further detected the Km value of virus to analysis the activity of neuraminidase of each virus.The growth curve of viruses in 2013 and 2014reached peak 48 hours after infection,maintained at high level until 72 hours,then the virus titer declined gradually,however the virus isolated in 2015 reached peak 24 hours after infection.The reassortment strain B/Fujian Tongan/1565/2013 has the similar growth characteristics with the wild type virus on the same year.Meanwhile the growth curve of other inter-lineage viruses in 2014 and 2015is lower than that of wild type viruses.We determined neuraminidase kinetic constants of all viruses.The reassortment strain B/Fujian Tongan/1565/2013 has the strongest affinity of neuraminidase.The results of 2014-2015virus suggest that the stronger affinity of neuraminidase of virus the better growth characteristics of virus.But the virus in 2013 is lack of such relationship between the growth characteristics and activity of neuraminidase.The neuraminidase activity and growth characteristics of inter-lineage reassortments due to surface protein gene exchange is not consistent,suggesting internal virus protein might have affected the growth characteristics of the viruses2013-2015,and pending further study.