含E型沙眼衣原体MOMP基因的重组腺病毒和DNA疫苗联合免疫效果的研究

Immune responses induced by DNA vaccine combined with recombinant adenovirns containing MOMP gene of Chlamydia trachomatis serovar E

目的探讨E型沙眼衣原体（Q）主要外膜蛋白（MOMP）DNA疫苗和重组腺病毒联合免疫小鼠诱导的免疫效应。方法构建、纯化重组腺病毒Ad-MOMP及重组真核表达质粒pVAX1-MOMP。设计4种免疫方案，分别为DNA免疫（DNA组）、重组腺病毒免疫（Ad组）、DNA初次免疫一重组腺病毒加强免疫（DNA／Ad组）、重组腺病毒初次免疫-DNA加强免疫（Ad／DNA组）。末次免疫后2周检测小鼠血清特异IgG、IgG1、IgG2a、IgA抗体，阴道分泌物SIgA抗体及脾淋巴细胞分泌IFN-γ、IL-10水平。结果DNA组诱导较弱免疫应答，未产生sIgA抗体及Th1反应。Ad组诱导出Th1反应及sIgA抗体，且血清抗体显著高于DNA组。联合免疫均能诱导明显强于单独免疫的黏膜sIgA、血清抗体及Th1反应。Ad／DNA组的Th1反应强于DNA／Ad组；而DNA／Ad组的血清抗体和黏膜抗体水平强于Ad／DNA组。结论Ad—MOMP能诱导黏膜免疫及Th1细胞免疫应答，DNA／Ad及Ad／DNA联合免疫产生的特异性免疫应答明显强于单独免疫。其中Ad／DNA的Th1反应优势更明显，DNA／Ad的血清抗体和黏膜抗体反应更强。接种顺序会影响联合免疫的强弱及类型，这为Ct疫苗的设计研究提供新的思路和实验依据。

Objective To investigate the specific immune responses induced by DNA vaccine com- bined with recombinant adenovirus carrying major outer membrane protein （MOMP） gene of Chlamydia trachom- ntis （Ct） serovar E. Methods Recombinant eukaryotic expression plasmid pVAX1-MOMP and recombinant adenovirus Ad-MOMP were constructed and purified. Four immunization strategies were designed including DNA immunization （DNA group）, recombinant adenovirus immunization （Ad group）, DNA prime-recombinant ade- novirus boost regimen （DNA/Ad group ） and recombinant adenovirus prime-DNA boost regimen （Ad/DNA group）. Two weeks after the final immunization, vaginal wash specimens, blood samples and spleens were col- lected from all mice for the evaluation of humoral and cellular immune responses. Results Thl responses and mucosal responses were not found in DNA group. Ad group induced both Thl responses and local mucosal re- sponses, and its IgG and IgA levels were significantly higher than those in DNA group. DNA/Ad group and Ad/ DNA group induced stronger Thl responses and humoral responses than DNA and Ad group. Serum antibodies and mucosal antibodies in DNA/Ad group were higher than those in Ad/DNA group, but Thl responses in DNA/Ad group were impaired than those in Ad/DNA group. Conclusion The recombinant adenovirus could induce Thl responses and genital mucosal responses. Combined immunization of DNA/Ad or Ad/DNA showed enhanced specific immune responses in comparison with the single immunization with DNA or Ad. The differ- ences between the two combination methods were that DNA/Ad group stimulated higher levels of specific anti- body responses, while Ad/DNA group produced stronger Thl responses. The study provided a reference for the enhancement and development of vaccines against Chlamydia trachomatis in further studies.