HBV基因疫苗诱导正常及HBV转基因小鼠产生体液免疫应答

HBV DNA-based immunization inducing humoral immune response in nomal and HBV tr ansgenic mice

目的 :用乙型肝炎病毒 (HBV)蛋白基因真核表达载体诱导正常小鼠及 HBV转基因小鼠产生特异性体液免疫应答 ,以探讨其预防及治疗 HBV慢性感染的可行性。方法 :将 HBV S2 .S基因的真核表达载体 p CMV- S2 .S(PS)和相应的空载体 pc D-NA3.0分别免疫正常 C5 7BL/ 6小鼠及同一品系 HBV转基因小鼠 (n=5 )。每只小鼠肌内注射纯化质粒 1 0 0 μg。用 EL ISA方法检测小鼠血清抗 HBs和抗 pre S2效价及 HBV转基因小鼠血清 HBs Ag和 HBe Ag的水平。注射基因疫苗后第 8周 ,活检取转基因小鼠肝脏组织 ,制备石蜡切片并行 H- E染色 ,光镜下观察其病理改变。 结果 :PS诱导正常及转基因小鼠产生了抗 HBs及抗pre S2 ,并且抗 pre S2的出现早于抗 HBs约 1～ 2周。PS免疫 8周后 ,转基因小鼠血清 HBs Ag和 HBe Ag为阴性。注射基因疫苗后第 8周病理检查转基因小鼠肝脏组织 ,肝细胞出现程度不同的广泛浊肿和水样变性 ,而相应的对照组无明显改变。免疫前后肝组织内单个核淋巴细胞数量无显著变化。结论 :研究表明 HBV中蛋白基因疫苗能够有效诱导 HBs Ag特异性的体液免疫应答 ,能够清除转基因小鼠血清中的 HBs Ag和 HBe Ag;初步的实验结果为研制治疗

Objective:To investigate the feasibility of treating chronic HBV infection by inducing spe cific humoral immune response to HBV middle envelope protiens in normal and HBV transgenic mice with HBV DNA based immunization. Methods: The eukaryotic expression vector pCMV S2.S (PS) containing HBV S2.S gene and pc DNA3.0 were used respectively to immunize 5 C57BL/6 normal mice and HBV transgen ic mice. Each mouse was injected intramuscularly with one of those plasmids at t he same dose (100 μg). Sera of mice were detected for anti HBs, anti preS2, HBsAg and HBeAg with ELISA. Pathological changes of transgenic mice liver were o bserved by microscopy. Results:PS can stimulate immune respons es of anti HBs and anti preS2 in normal and transgenic mice.The appearance of a nti preS2 was 1 2 weeks earlier than that of anti HBs. HBsAg and HBeAg in se ra turned negative 8 weeks after immunization. At the 8th week, hepatocytes show ed extensive granular degeneration and hydropic degeneration. There was no obvious difference in the amount of mononuclear lymphocytes between pre and post gen e immunization. Conclusion: It is showed that specific humoral immune response can be effectively induced by PS after DNA based immunization, and PS seems to be responsible for the disapearance of HBsAg and HBeAg in sera o f HBV transgenic mice. The results provide an evidence for furth er investigation of genetic vaccine in the treatment of chronic HBV infection.