白介素2基因佐剂对沙眼衣原体E型DNA疫苗的免疫增效作用

Immune enhancing effects of interleukin 2 genetic adjuvant on DNA vaccine against Chlamydia trachomatis serovar E

目的探讨小鼠白介素2重组质粒对沙眼衣原体E型DNA疫苗细胞免疫效果的影响。方法以BALB／c小鼠为实验动物，采用肌内接种免疫的方式，将小鼠分为接种空质粒的阴性对照组、DNA疫苗免疫组、DNA疫苗联合小鼠白介素2重组质粒免疫组和接种灭活沙眼衣原体E型原体的阳性对照组，观察小鼠后足垫局部的肿胀情况、脾淋巴细胞增殖试验、血清IL-4和IFN-γ水平和同型沙眼衣原体生殖道攻击后局部的衣原体培养情况。结果4组实验动物的脾淋巴细胞增殖指数分别为1．37±0．21、2．524-0．30、3．644-0．41、3．774-0．34，联合免疫组和阳性对照组比较差异无统计学意义，与另2组比较，差异有统计学意义。4组的血清IL4分别为（25．37±18．93）、（24．75±8．49）、（21．74±6．43）、（38．49±12．24）pg／ml，灭活原体组高于其他各组；4个组的血清IFN-γ分别为（310．8±160．7）pg／ml、（601．3±357．9）pg／ml、（1923．3±518．1）pg／ml、（2712．5±887．2）pg／ml，联合免疫组和阳性对照组相当，与另两组比较，差异有统计学意义。沙眼衣原体E型原体攻击后，空质粒组小鼠生殖道局部能够培养出衣原体；另3个组衣原体培养阴性。结论白介素2基因佐剂能够增强沙眼衣原体E型DNA疫苗的细胞免疫效应，且以Th1型反应为主。

Objective To study the effect of a recombinant plasmid encoding mouse interleukin 2 （rolL-2） on the immunogenicity of DNA vaccine against Chlamydia traehomatis （Ct） serovar E. Methods BALB/c mice were divided into 4 groups to be intramuscularly inoculated with blank plasmid （negative control group）, DNA vaccine against Ct serovar E （DNA vaccine group）, DNA vaccine against Ct serovar E and a recombinant plasmid containing raiL-2 （combination group）, and inactivated Ct serovar E elementary bodies （positive control group）, respectively. The immunological effects were evaluated by posterior foot pad thickness, proliferation level of spleen lymphocytes, serum level of IL-4 and interferon （IFN）-γin mice, and the capability to clear Ct genital tract infection. Results The proliferation index of spleen lymphocytes in the combination group and positive control group was similar （3.64 ± 0.41 vs. 3.77 ±0.34）, but was significantly different from that in the blank control group and DNA vaccine group （1.37± 0.21 and 2.52 ± 0.30）. The serum level of IL-4 was （38.49 ± 12.24） pg/ml in the positive control group, significantly higher than in the negative control group, DNA vaccine group and combination group （（25.37 ±18.93）, （24.75 ± 8.49）, （21.74± 6.43） pg/ml,respectively）. With respect to the serum level of IFN-γ, the combination group and positive control group were similar （1923.3 ± 518.1 ） pg/ml vs. （2712.5 ±887.2） pg/ml）, but were significantly different from the negative control group and vaccine group （ （310.8 ± 160.7） pg/ml and （601.3 ± 357.9） pg/ml）. Six days after Ct challenge, the exfoliated cells from genital tract were positive for Ct culture in the negative control group, but negative in the other 3 groups. Conclusion IL-2 genetic adjuvant can enhance the immune response, especially Thl type response, induced by the DNA vaccine against Ct serovar E.