沙眼衣原体重组口服活疫苗的构建及其口服免疫的特性

Construction and immunological properties of a recombinant live vaccine against Chlamydia trachomatis

目的 观察所构建的沙眼衣原体 (Ct)重组疫苗株对小鼠的免疫特性 .方法 以减毒鼠伤寒杆菌致死性平衡系统为载体构建 Ct重组疫苗株 .将重组疫苗株用 L B培养基连续传代 5 0次 ,比较传代前后携带质粒、生化反应性及蛋白表达情况 ,以鉴定重组子的稳定性 .并以不同浓度的重组菌活菌液口服免疫 BAL B/c小鼠 ,检测外源基因的插入和表达对减毒株毒性的影响 .口服免疫后不同时间检测小鼠小肠 Peyer氏结、肠系膜淋巴结、脾脏及子宫粘膜的重组菌的分布 .结果 重组菌连续传代 5 0次保持稳定 ,并具有较好的安全性 .所构建的菌株仍保持在小肠、肠系膜淋巴结、脾脏及粘膜等的定居能力 .结论 所构建的重组疫苗株具有较好的稳定性和安全性 。

AIM To investigate the immunological properties of a recombinant live oral vaccine against Chlamydia trachomatis. METHODS A live vaccine against C. trachomatis was constructed by using an attenuated Salmonella typhi-murium as vehicle. The stability of the vaccine was detected by plasmid analysis, biochemical test and SDS-PAGE after being inoculated for 50 generations. The safety was observed by oral administration with the recombinant vaccine strain of different concentration. Peyer's patch, spleen, mesenteric lymph nodes and uterus were removed from mice immunized with recombinant vaccine after different days and colony formation units (CFU) were numerated on LB agar plates with nalidixic acid after homogenizing. RESULTS All the mice were alive 21 days after oral administration of up to 5×10 11 CFU of recombinant vaccine, which was more than one million times higher than the LD50 of wild-type administrated orally. Colonization of the vaccine strain on different tissue lasted for up to 28 days. CONCLUSION The vaccine strain is stable and safe when used as an oral live vaccine for mice. The expression of exogenous gene does not make the vaccine vehicle lose its ability to invade and colonize.