目的　研究乙脑病毒prME、E蛋白的体外表达特点 ,比较不同重组质粒所进行的DNA免疫效率。方法　分别将乙脑病毒 (JaGAr 0 1株 )prME、E蛋白编码基因 (2 0 0 1bp、15 0 0bp)构建于融合FLAG标记基因的真核表达载体pcDNA(FLAG) 3上 (pJME、pJE) ,脂质体法将二重组质粒转染于HepG2及COS 1细胞系 ;采用不同抗体系统 (anti FLAG、anti E) ,经Westernblot法检测乙脑病毒prME[相对分子质量 (Mr)约 72× 10 3]与E(Mr 约 5 4× 10 3)蛋白表达水平 ;将质粒肌注BALB c鼠 ,二次免疫后 3周 ,腹腔注射乙脑病毒 (10 5PFU 10 0 μl)作为病毒攻击并观察 2 1d。 80 %空斑减少中和实验法检测中和抗体滴度变化。结果　anti FLAG可检测到由质粒pJME、pJE编码的相应蛋白产物在转染细胞内表达 ,同时在pJME转染的细胞内检测到一个新的 11× 10 3的低Mr 蛋白。anti E仅在pJME转染的细胞内检测到E蛋白。肌注pJME可产生高水平中和抗体滴度以及诱导有效的保护性免疫 ,效果等同于普通灭活JE疫苗 ,但优于pJE。结论　pJME的体外表达水平优于pJE。DNA免疫实验结果与prME、E蛋白体外表达特点相一致 Objective To study the in vitro expression of prME and E protein of Japanese encephalitis virus (JEV) and to compare the DNA immunization efficiency of different recombinant plasmids. Methods The coding sequence of prME and E protein of JaGAr 0 1 strain (200bp and 150bp) was constructed on the eukaryotic expression vector pcDNA (FLAG) 3 fused with FLAG marker gene (pJME, pJE) The recombinant plasmids were transfected into HepG2 and COS-1 cell lines by lipofectamine. Anti-FLAG (anti-E) antibody was used to detect JEV prME [Mr (molecular weight) about 72 × 10 3], and E (Mr about 54 × 10 3). BALB mice were intramuscularly injected with plasmids. After 3 weeks of secondary immunization, JE virus (10 5 PFU 10 0 μl) was intraperitoneally injected as a virus and observed 1d. Neutralizing antibody titers were detected by 80% plaque reduction and neutralization test. Results Anti FLAG detected that the corresponding protein product encoded by plasmid pJME and pJE was expressed in transfected cells and a new 11 × 10 3 protein with low Mr was detected in pJME transfected cells. Anti E E protein was detected only in pJME transfected cells. Intramuscular pJME produces high levels of neutralizing antibody titers and induces potent protective immunity, with the same effect as the normal inactivated JE vaccine but superior to pJE. Conclusion pJME is better than pJE in vitro. DNA immunization results with prME, E protein in vitro expression characteristics consistent