增强基因疫苗免疫效果的研究

Based on coxsackievirus group B type 3 (CVB3) Vp1 gene , we established 2 cytoplasmic gene expression systems。One is the recombinant plasmid pT7-EMC-Vp1 with T7 operator and plasmid pAR 3132 that codes T7 RNA polymerase ; Other is plasmid pT7-CB3-5.3 that contain 1~5361 nucleotides of CVB3 with T7 operator and the same plasmid pAR 3132 .After transformation of pT7-EMC-Vp1 and pAR 3132 or pT7-CB3-5.3 and pAR 3132 into HeLa cell and murine macrophages ,we found that the amount of gene expression products in this two systems are 2~4 times as high as that of transformed eukaryote expression plasmid pcDNA3-Vp1.For studying the effect of the cytoplasmic gene expression system in vivo , the pT7-EMC-Vp1 and pAR 3132 are transformed into the attenuated S. typhimurium .Then mice are immunized orally with the bacterial transformed . The results showed that the mice immunized produced stronger humoral immune response and cell-mediated immune response than that of control group. When the mice were challenged with CVB3 , a evident protection was observed . When compared with the immunization by nude plasmid pcDNA3-Vp1 via muscular injection，oral immunization with attenuated S. typhimurium transformed could induce sIgA and stronger effect of cytotoxicity and IgG 。

以CVB3为对象，利用含T7启动子的基因疫苗质粒pT7EMC-VP1及构建T7RNA聚合酶表达质粒pcDNA3-T7RNApolymerase，建立胞浆基因表达系统，然后以减毒鼠伤寒菌作载体通过口服将这礁鲋柿Ｍ贝牖迕庖呦赴校怪诎斜泶铮云谟盏记刻逡骸⑾赴庖叻从岸訡VB病毒攻击的保护作用。解决常规基因疫苗免疫水平较低等问题及达到防治CVB病毒性心⊙椎哪康摹?..