New gene expression vector using duck hepatitis B virus

研究了一种新型亲肝基因表达载体--鸭乙型肝炎病毒(DHBVd)。将含有野生型DHBVDNA的质粒DNA与脂质体复合，注射到1日龄北京鸭的外周静脉中。DHBVDNA仅在肝细胞中表达，并可检测到病毒复制。DHBVDNA突变株在接种后2周即可表达，并在血清中检测到复制病毒，但16周后血清病毒滴度明显低于野生型。前C区突变型感染肝脏的组织学分析显示，部分动物出现炎症和轻度纤维化，相当于慢性肝炎，提示与前C区蛋白相关的发病机制有待下一步分析。构建了在前C区插入24个碱基的克隆，接种鸭体内，获得野生型病毒的复制。外源基因插入DHBVDNA的稳定性和容量有待进一步研究。

New hepatotropic gene expression vector using the animal model of hepatitis B virus, duck hepatitis B virus (DHBV) was investigated. Plasmid DNA containing wild type of DHBV DNA was complexed with liposome, and injected into the peripheral vein of one-day-old Pekin duck. DHBV DNA was expressed exclusively in the hepatocytes and virus replication was detected. Precore defective mutant was constructed by one base insertion into precore ORF.The mutant DHBV DNA was also expressed and replicated virus was detected in the serum 2 weeks after inoculation, but virus titer in the serum was much less than wild type after 16 weeks. Histological analysis of precore mutant infected liver showed that some of the animals had the inflammation and slight fibrosis which equivalent to the chronic hepatitis, indicating that the pathogenesis related to the precore protein would be suggested and should be analyzed for the next step. The clone with 24 bases insertion in the precore ORF was constructed and inoculated into the ducks resulted the wild type virus replication. The stability and the capacity of foreign gene inserted into DHBV DNA needed to be analyzed.