Inhibition of dental plaque formation and determination of anti-cariogenic effect by DNA vaccine

变形链球菌的糖基转移酶（GTFs）是一种由蔗糖合成黏附葡聚糖的酶，是龋病的重要毒力因子。本研究的目的是：1)测定GTF结构域的免疫原性，选择抗龋DNA疫苗的靶区；2)构建针对候选结构域的DNA疫苗；3)分析DNA疫苗的抗龋效果。gtf通常具有三个结构域（可变结构域、催化结构域和葡聚糖结合结构域）。利用Paker's法预测各结构域的抗原性，构建了携带变形链球菌MT8148这些结构域的重组质粒。Western blot分析显示，催化区和葡聚糖结合区免疫原性较低。另一方面，可变区被认为具有免疫原性。利用携带腺病毒启动子的pAFC3构建了含GTF可变区DNA疫苗质粒。将疫苗质粒转染293细胞，通过northern blot分析证实mRNA的表达。下一步，我们将在体外和体内（动物）实验中确定DNA疫苗的抗龋活性。

Glucosyltransferases(GTFs) from Streptococcus mutans synthesis the adhesive glucans from sucrose and are important virulence factor of dental caries. The purposes of this investigation are : 1)Determination of the immunogenicity of GTF domains to select target region of anti-caries DNA vaccine, 2)Construct DNA vaccine against the candidate domain, 3)Analysis of anti-cariogenic effect of the DNA vaccine.GTFs commonly possesses three (variable, catalytic, and glucan-binding) domains. Antigenicity of each domain was predicted by Paker's method, then the recombinant plasmids carrying these domains of GTFs from S.mutans MT8148 were constructed. Western blot analysis revealed that immunogenicity of the catalytic and glucan-binding regions was low. On the other hand, the variable region was thought to possess immunogenicity.DNA vaccine plasmid containig the variable region of GTF was constructed using pAFC3 which was carrying the adeno virus promoter. The vaccine plasmid was transfected into 293 cells and the expression of mRNA was confirmed by Northen blot analysis.To the next step, we will determine the anti-cariogenic activity of the DNA vaccine in in vitro and in vivo (animal) experiments.