乳鼠接种编码乙型脑炎病毒PrM/E蛋白的重组质粒DNA可诱发保护性免疫

Injection of recombinant plasmid DNA coding Japanese encephalitis virus E protein induces protective immunity in suckling mice

目的 :评价乙型脑炎DNA疫苗对乳鼠的免疫保护效果 .方法 :以DNA疫苗 (pV/JE)、质粒载体对照 (pVAX1)和PBS接种BALB/c乳鼠后 ,测定其病毒特异性的CTL活性、结合抗体、中和抗体 ,并以 10 0LD50 JEV攻击 ,观察保护效果 .结果 :DNA疫苗组的CTL活性为 37.5 % ,而载体和PBS对照组的CTL活性分别为 18%和 8.5 % .二次免疫后DNA疫苗组的免疫荧光抗体滴度为 1∶2 8.3(几何平均效价 ) ,抗体阳转率为 80 % (8/10 ) ;混合血清的中和抗体效价为 1∶4 0 .JEV攻击后 ,DNA疫苗组小鼠获得 75 % (6 /8)的保护率 ,而对照组小鼠全部死亡 .结论 :所构建的DNA疫苗可诱发乳鼠产生抗JEV的CTL活性、中和抗体及保护活性 。

AIM: To evaluate Japanese encephalitis (JE) DNA vaccine (pV/JE) in protecting immunized suckling mice against Japanese encephalitis virus (JEV). METHODS: After immunized twice with the JEV DNA vaccine, the cytotoxic T lymphocyte (CTL) activity, immunoflouresence anti JEV antibody and JEV specific neutralizing antibody were detected. The immunized mice were challenged with 100 LD50 JEV. RESULTS: CTL activity in mice immunized with the DNA vaccine was 37.5 % but only 18% and 8.5% in vector and PBS control groups, respectively. DNA vaccine group showed a seroconversion of 80% (8/10) with immuno flouresence antibody 1∶28.3 (geometrical mean titer). Neutralizing antibody of the mix sera was also detectable (=1∶40) in mice immunized with the neonatal vaccines. Six immunized mice survived from the challenge with 100 LD50 JEV, compared with that all mice dead in vector and PBS control groups. CONCLUSION: Constructed DNA vaccine can induce JEV specific CTL activity, neutralizing antibody and protect immunized mice from JEV challenge, which provides important data for the production of neonatal vaccines against JEV.