DNA防龋疫苗诱导长期免疫反应及机制初探

Experiment Study of Anti-Carious Vaccine Inducing Long-Term Immune Responses and the Mechanism

目的:观察编码pac结构基因A-P片段的重组质粒pCIA-P以经肌肉和颌下腺周围区域皮下注射(TSG)两种途径免疫BALB/c小鼠后的特异性免疫反应,并观察表面蛋白抗原PAc在小鼠颌下腺中的表达。方法:将20只BALB/c小鼠随机分为4组,分别以重组质粒pCIA-P经肌肉、颌下腺区周围区域皮下注射两种途径免疫小鼠及pCI质粒和生理盐水肌肉免疫小鼠,ELISA法检测血清和唾液中特异性抗体水平动态变化。将pCIA-P经颌下腺区周围区域皮下注射以免疫组化技术观察表面蛋白抗原PAc的表达。结果:颌下腺区皮下注射法免疫后唾液IgA型特异性抗体和血清IgG型特异性抗体均明显升高,并持续24周以上。肌肉注射法后血清IgG型特异性抗体明显升高,但未有效诱导产生唾液IgA型特异性抗体。在小鼠颌下腺中检测到PAc蛋白的表达。结论:DNA防龋疫苗经颌下腺周围区域皮下注射免疫是可诱导长期黏膜免疫的有效途径。

Objective： To observe immune responses of BALB/c mice after they were immunized with plasmid DNA pCIA-P encoding S. mutans surface protein PAC by intramuscular injection or targeted salivary gland immunization （TSG）. Plasmid DNA pCIA-P was delivered through TSG and the expression of PAc in submandibular gland was detected. Methods： Ten BALB/c mice were immunized with plasmid pCIA-P by intramuscular injection （n=5） or TSG （n=5）. Another ten mice were immunized with plasmid pCI （n=5） or physiological saline （n=5） by intramuscular injection as controls. The levels of specific antibodies in sera and saliva were determined by ELISA. Immunohistochemistry technique was used to detect the expression of PAc in the submandibular glands of mice. Results： The level of serum specific anti-PAc IgG and salivary specific anti-PAc IgA in TSG immunization groups were significantly higher than those of other groups. And this has continued for more than 24 weeks. The intramuscular immunization group produced higher level of serum specific anti-PAc IgG significantly than control groups, but failed to induce specific local mucosal immune response. PAc was expressed in submandibular glands. Conclusion： TSG immunization are effective genetic immunization routes to delivery preventing dental caries DNA vaccine and induce long-term local mucosal immune response.