中文摘要：

为构建能够在MDCK细胞中高水平复制的H9N2亚型禽流感病毒（AIV）疫苗株，本研究在对病毒生长特性及HA基因遗传进化分析的基础上，筛选出一株细胞高度适应的国内流行株A／chicken／Shanghai／11／2011（H9N2）（SHll），并通过反向遗传操作技术拯救出全部基因均来自亲本株的AIVrSHll株。生物学试验结果表明rSHll在鸡胚半数感染量（EID50）、组织培养半数感染量（TCID50）、遗传稳定性等方面均与亲本株保持一致，rSHll经MDCK细胞连续传5代后血凝价稳定在1：1024，表明该病毒株具有细胞高度增殖的特性。采用rSHll株制备油乳剂灭活苗免疫4周龄SPF鸡，免疫一周即可以检测出HI抗体，免疫3周后HI抗体平均效价高于1：700，表明其具有良好的免疫原性。rSHll疫苗对不同的H9N2病毒株能够产生良好的免疫保护作用，显著抑制免疫鸡排毒。H9N2亚型AIV细胞高产株的拯救为该亚型AIV细胞苗的研制奠定了基础。

英文摘要：

To construct high-yield H9N2 subtype avian influenza virus （AIV） candidate vaccine strain propagating in MDCK cells by the reverse genetics, A/chicken/Shanghai/01/2011 （H9N2） （SH11） was chosen from six isolates based on cell-growth characteristics and HA phylogenetic analysis. The rescued virus rSH11 and the wild type virus shared similar biological properties such as EIDs0, TCIDs0 and genetic stability. The steady HI titer of 1：1 024 of the high-yield rSH11 was achieved after 5 passages in MDCK cells. Furthermore, the HI antibodies were detected from SPF chickens immunized with oil-emulsified inactivated vaccine at one week post-vaccination, and more than 1：700 were achieved at three weeks post-vaccination. The rSHll vaccine can dramaticlly reduced shedding challenged virus from the vaccinated SPF chicks. The rescue of H9N2 virus laid the foundation for the production of cell grown influenza vaccine.