中文摘要：

目的观察含乙肝病毒（hepatitis B virus，HBV）preS2S基因的核酸疫苗免疫小鼠后的特异性免疫应答。方法将BALB／c小鼠随机分为4组分别肌肉接种pCMV。S2S、乙肝表面抗原（HBsAg）、空载质粒（pCMV）及生理盐水（NS）。免疫组织化学法检测接种局部组织preS2S抗原的表达，乳酸脱氢酶（LDH）释放法检测特异性CTL活性，ELISA法检测小鼠血清特异性抗体Anti-HBs。结果pCMV-S2S组小鼠肌肉细胞中有较多量的preS2S蛋白表达，其它小鼠肌肉细胞中均未检出preS2S蛋白表达。pCMV-S2S组小鼠CTL活性为（32．10±1．93）％，明显高于各对照组（P〈0．05）。pCMV-S2S组小鼠8周后Anti-HBs阳性率最高为42．9％。HBsAg组小鼠4周时Anti-HBs阳性率即达到100％。pCMV组及Ns组小鼠血清中均未检测出Anti—HBs。结论乙肝核酸疫苗pCMV—S2S能在小鼠体内表达preS2S蛋白，并能在小鼠体内诱生较强的特异性CTL活性，也能诱生一定程度的特异性体液免疫应答。

英文摘要：

Objective To investigate the specific immune responses induced by a hepatitis B virus（HBV） preS2S DNA vaccine on BALB/c mice. Methods BALB/c mice were randomly divided into 4 groups, and intramuscularly injected with pCMV-S2S, HBsAg, pCMV or normal saline thrice,at week 0,4 and 8 respectively. The expression of preS2S antigen in mice muscle was detected by immunohistochemistry assays. The specific CTL activity of mice was measured by lactate dehydrogenase （LDH） release assays. The anti-HBs in mice serum was measured by ELISA assays. Results The expression of preS2S antigen was detected in the muscles of pCMV-S2S group mice,but not detected in the muscles of other group mice. The specific CTL lysis value of pCMV-S2S group mice was[（32.10± 1.93 ） % ） ] （ E/T ratio was 25：1 ）, remarkably higher than that of other groups（ P 〈 0.05 ）. The highest anti-HBs rate of pCMV-S2S group mice was 42.9% ,8 weeks post the initial injection. However anti-HBs rate of HBsAg group mice was 100% ,4 weeks post the initial injection. No anti-HBs were detected in the other gwo groups. Conclusion The HBV DNA vaccine pCMV-S2S may elicit HBV preS2S antigen expression,induce substantial HBV preS2S-specific CTL response in vivo,and may induce anti-HBs to some extent.