目的:构建含HDV核酶基因的重组逆转录病毒载体,包装出逆转录病毒实现其在HepG2215细胞中稳定表达,并研究其是否抑制HBV的复制。方法:应用PcR方法扩增HDV核酶基因,克隆入逆转录病毒载体pMSCVIU6中,用脂质体法转染逆转录病毒载体包装细胞,嘌呤霉素筛选稳定表达细胞株,用PCR和药物抗性水平传播分析检测野生型辅助病毒。收获的病毒感染HepG2215细胞,用酶联免疫实验测定对HBV的抑制率。结果:重组逆转录病毒载体的酶切鉴定片段约为73bp,与预期值一致。脂质体转染包装细胞,嘌呤霉素加压筛选出高病毒滴度(4.0×10^6CFU/ml)的细胞克隆,且未检测到辅助病毒,对HBV的抑制率最高可达61.56%。结论:成功构建重组逆转录病毒载体,在包装细胞系中能生产出高滴度的逆转录病毒,能有效的抑制HepG2215细胞内HBV的复制,为HBV的基因治疗提供了实验数据。
Objective: To establish a retroviral vector containing the HDV ribozyme and a stable vector production cell line for HBV treatment. Methods: The HDV ribozyme gene was cloned by PCR using ptVHRZ as a template and recombinated with pMSCV/U6, which had Puromycin resistance gene. The recombinant of HDV ribozyme was evaluated by enzyme digestion and sequencing. The pMSCV/U6-HDVRZ was transfected to pack a cell line with lipofectamine 2000. The titer of the recombinant virus in the. supematant was assayed on NIH3T3 cells. The helper virus was tested by both the PCR and a marker rescue assay. The high-fiter cell lines were chosen for culture, and then the cleavage activity of the retroviral containing the HDV ribozyme was studied in HepG2215 cells by ELISA. Results: The retroviral vector containing the HDV ribozyme was successfully established. The vector production cell lines were established. The highest titer was 4.0 × 10^6 CFU/ml. HDV ribozyme gene integration was detected by PCR. The retrovims was free of a helper virus. The levels of HBsAg of ribozyme groups were significantly lower than those of the control group, proving the HDV ribozyme had HBV-specifie cleavage activity in HepG2215 cells. Conclusion: A retroviral vector containing the HDV ribozyme and a high-titer vector production cell line are successfully constructed. The HBV-specific HDV ribozyme can catalyze the sequence-specific RNA, and suppress the replication of HBV. The retrovirus carrying the ribozyme gene has the potential of being further explored in gene therapy for HBV infection.