小鼠白细胞介素-21基因重组腺病毒可控制慢性HBV感染

目的 观察小鼠白细胞介素-21基因重组腺病毒(Ad-GFP-mIL-21)在慢性HBV感染小鼠中的表达以及其对病毒清除和HBV特异性抗体产生的作用.方法 Ad-GFP-mIL-21体外感染HepG2.2.15细胞后分别采用ELISA和Western blot检测上清和细胞mIL-21的表达;尾静脉注射rAAV8-1.3HBV至野生型C57BL/6小鼠体内建立HBV持续表达模型,12周后实验组尾静脉注射Ad-GFP-mIL-21,以注射空载GFP重组腺病毒或PBS为对照组,荧光显微镜观察Ad-GFP-mIL-21在小鼠体内各器官的表达情况,ELISA检测各组小鼠血清HBsAg、HBsAb、HBcAb和mIL-21的水平.结果 Ad-GFP-mIL21可在体外感染HepG2.2.15细胞,且上清mIL-21水平与重组载体的滴度和感染时间相关.注射Ad-GFP-mIL21至HBV持续表达小鼠后第4天观察到绿色荧光主要在肝细胞表达;与处理前相比,注射第4天血清mIL-21水平显著升高(P<0.05),而HBsAg滴度则明显下降;实验组和对照组小鼠在注射第13天血清HBsAb均为阴性;与对照组相比,实验组小鼠血清HBcAb水平显著升高(P<0.05).结论 Ad-GFP-mIL-21在HBV持续感染小鼠体内可表达mIL-21,并能下调血清HBsAg滴度和促进HBcAb产生,提示其在体内具有控制慢性HBV感染的作用.

A recombinant adenovirus vector carrying murine interleukin-21 gene controls chronic HBV infection in mice

Objective To investigate the effect of an adenovirus vector containing murine interleukin-21 gene (Ad-GFP-mIL-21) in virus clearance and on the production of HBV-specific antibodies in mice with persistent HBV infection. Methods ELISA and Western blot analysis were used to detect the expression of mIL-21 in the supernatant and cytoplasm of cultured HepG2.2.15 cells after infection by Ad-GFP-mIL-21. Mouse models of chronic HBV infection established by in vivo transduction with rAAV8-1.3HBV were divided into 3 groups for treatment 12 weeks later with injection of Ad-GFP-mIL-21, GFP recombinant adenovirus or PBS via the tail vein. Serum levels of HBsAg, HBsAb, HBcAb, and mIL-21 in the mice were detected using ELISA, and the expression of Ad-GFP-mIL-21 in the organs was observed by fluorescent microscopy at different time points after the injection. Results Ad-GFP-mIL-21 was capable of infecting HepG2.2.15 cells in vitro, and the levels of mIL-21 in the supernatant were correlated with the titers of adenovirus administered and the infection time. In the mice with persistent HBV infection, green fluorescence expression was observed almost exclusively in the liver on day 4 after injection of Ad-GFP-mIL21, and serum levels of IL-21 increased significantly compared with the level before treatment (P<0.05). Although HBsAb was undetectable in both Ad-GFP-mIL21-injected and control mice on day 13, a significantly higher serum level of HBcAb was detected in the mice with Ad-GFP-mIL21 injection (P<0.05). Conclusion Ad-GFP-mIL-21 can efficiently express mIL-21 in mice with chronic HBV infection to downregulate serum levels of HBsAg and promote HBcAb production, suggesting its efficacy in controlling chronic HBV infection.