利用293细胞拯救和扩增重组人41型腺病毒

Rescue and Amplification of Recombinant Human Adenovirus Type 41 in 293 Cells

人41型腺病毒(Human adenovirus type 41,HAdV-41)为难养腺病毒,E1区缺失的HAdV-41无法在293细胞中拯救并扩增,本研究试图通过反向遗传学操作获得能够在293细胞中拯救并扩增的重组HAdV-41。首先,对原有的骨架质粒pAdbone41进行改造:通过重叠延伸PCR方法将HAdV-41的E3区基因替换为HAdV-5E4orf6编码区;将HAdV-5E1A增强子克隆至HAdV-41E4区启动子上游,获得新的骨架质粒pAdbone41E4EE。该骨架质粒与线性化的穿梭质粒pSh41-GFP在E.coli BJ5183菌株同源重组得到腺病毒质粒pAd41E4EE-GFP。pAd41E4EE-GFP经Pme I酶切线性化后转染293细胞,拯救出重组病毒HAdV-41-E4EE-GFP。经过7轮扩增,超速离心纯化后获得1.0ml浓度为8.0×10^(10) vp/mL的重组腺病毒,其感染滴度为1.7×10~9 IU/mL,电子显微镜下观察可见形态完整的病毒颗粒,限制性内切酶酶切分析及PCR鉴定结果均表明携带HAdV-5E4orf6基因与E1A增强子基因的重组腺病毒载体构建正确。本研究利用反向遗传学技术对病毒载体进行改造,实现了在293细胞中培养E1区缺失的HAdV-41的目的。

Human adenovirus type 41 （HAdV-41） is considered to be a ＂fastidious adenovirus＂. El-deleted HAdV-41 cannot be rescued or amplified in 293 cells. To propagate recombinant HAdV-41 in 293 cells, the backbone plasmid pAdbone41 was reconstructed. That is, the E3 coding sequence of HAdV-41 was de- leted and replaced with the HAdV-5 E4orf6 gene; and the EIA enhancer of HAdV-5 was inserted up- stream of the E4 promoter of HAdV-41. Novel adenoviral plasmid pAd41E4EE-GFP was generated by ho- mologous recombination of the shuttle plasmid pSh41-GFP with the modified backbone plasmid in the Escheriehia coli BJ5183 strain. Adenovirus HAdV-41-E4EE-GFP was rescued by transfecting 293 cells with linearized pAd41E4EE-GFP. After seven rounds of propagation, viruses were purified by the CsC1 ul- tracentrifugation method. HAdV-41-E4EE-GFP in 1.0 ml with a particle titer of 8 ×10^10 vp/mL was ob- tained which had a particle-to-infectious ratio of 50 ： 1. The genome of HAdV-41-E4EE-GFP was con- firmed by restriction analyses and polymerase chain reaction. These results showed that a novel HAdV-41 vector system was established in which recombinant HAdV-41 could be constructed and packaged in 293 cells.