比较不同血清型AAV携带HBV基因组建立乙肝小鼠模型效果

Comparison of HBV persistent infection mice models by different serotypes of AAVs carrying HBV genomes

摘要:

近年来，用8型腺相关病毒携带1.3拷贝HBV (Hepatitis B virus) 基因组建立的HBV持续感染小鼠模型受到越来越多的关注。本研究比较了除AAV8之外的其他4种血清型重组腺相关病毒 (Recombinant adeno-associated virus，rAAV) 建立乙肝小鼠模型效果。首先，将携带1.3拷贝ayw亚型HBV基因组的1型、2型、5型、8型、9型腺相关病毒分别以1×1011 vg/只 (Viral genome，vg) 的剂量尾静脉注射C57BL/6J小鼠；利用 ELISA 方法监测小鼠血清中HBeAg和HBsAg表达水平；用定量PCR方法检测小鼠血清和肝脏中 HBV DNA 拷贝数；用免疫组化方法检测小鼠肝脏中HBcAg的表达；用HE染色检测小鼠肝脏病理变化。结果显示，在持续8周中，5组小鼠血清中都检测到HBeAg和HBsAg的表达，血清和肝脏中均检测到HBV DNA的存在。HBeAg、HBsAg、HBV DNA表达水平高低依次为AAV8>AAV9>AAV1>AAV5>AAV2。5组小鼠用免疫组化方法都检测到肝脏中HBcAg表达，HE染色病理检测均观察到不同程度的肝损伤。本研究扩大了能用于建立乙肝小鼠持续感染模型可选择的AAV载体种类，发现虽然AAV1、2、5、9的建模效果不如AAV8，但它们都可以介导建立持续感染的乙肝小鼠模型，建模效果依次为AAV8>AAV9>AAV1>AAV5>AAV2。其中AAV9介导的建模效果与AAV8载体最为接近，可以替代AAV8载体用于有效地建立HBV持续感染的小鼠模型。

Abstract:

In recent years, Hepatitis B virus (HBV) persistent infection mouse model with recombinant adeno-associated virus 8 carrying 1.3 copies of HBV genome (rAAV8-1.3HBV) is concerned. We studied and compared the efficacy among HBV persistent infection mice models by other serotypes except AAV8. First, we prepared and purified five viruses: rAAV1-1.3HBV, rAAV2-1.3HBV, rAAV5-1.3HBV, rAAV8-1.3HBV and rAAV9-1.3HBV. Then we injected each virus into 3 C57BL/6J mice with the dose of 1×1011 vg (Viral genome, vg) per mouse. We detected HBsAg and HBeAg in sera by enzyme-linked immunosorbent assay (ELISA) at different time points post injection. We killed mice 8 weeks post injection and took blood and livers for assay. We detected copies of HBV DNA by real-time quantitative PCR in sera and livers. Meantime, we detected HBcAg in the livers of mice by immunohistochemistry and further performed pathology analysis of these livers. The five groups of mice, HBeAg and HBsAg expression sustained 8 weeks in serological detection and HBV DNA was both detected in sera and livers at the time of 8 weeks post injection. HBeAg, HBsAg, HBV DNA copies expression levels in descending order were AAV8>AAV9>AAV1>AAV5>AAV2. HBcAg expression was detected in livers as well. Varied degrees of liver damage were shown in five groups of mice. This study provides more alternative AAV vector species to establish a persistent infection with hepatitis B model.