pIL-12质粒DNA对细粒棘球蚴感染小鼠免疫应答的影响

Effects of plasmid DNA pIL-12 on the immune response of mice infected with hydatid cysts of Echinococcus granulosus

目的探讨pIL-12质粒DNA免疫对细粒棘球蚴感染小鼠免疫应答的影响。方法将pIL-12质粒DNA肌肉注射免疫BALB/c鼠,免疫后8w用Eg原头节进行攻击感染,感染后18w剖杀小鼠,计算减蚴率;取脾并分离脾细胞,流式细胞仪检测脾CD4+和CD8+T淋巴细胞亚群的百分比;用EgAg或ConA刺激培养脾细胞,收集脾细胞培养上清液,用试剂盒检测脾细胞培养上清液的IL-2、IFN-γ、TNF-α和IL-4水平;流式细胞仪检测脾细胞的凋亡发生率,同时设有BCG和PBS对照。结果pIL-12质粒DNA免疫组的减蚴率为44.85%,脾CD4+和CD8+T细胞亚群显著增加,IL-2、IFN-γ和TNF-α水平升高,IL-4水平降低,脾细胞凋亡发生率明显低于PBS对照组。结论pIL-12质粒DNA可诱导细粒棘球蚴感染小鼠产生一个保护性的免疫反应。

To investigate the effects of plasmid DNA plL-12 on the immune response of mice intected with hydatld cysts of Echinococcus granulosa ,BALB/c mice were immunized intramuscularly with plasmid DNA plL-12 and challenged by protoscoleces of E. granulosa 8 weeks after vaccination. Mice were killed 18 weeks after infection,and rate of reduction in hydatid cyst weight was counted. The splenocytes were isolated and the percentages of the splenic CD4^＋ and CD8^＋ T lymphocytes were measured by FACsort. In addition splenocytes were cultivated with stimulation of E. granulosus antigen or Con-A,and the levels of IL-2 ,GN-γ,TNF-α and IL-4 in the supernatants of cultures were determined by ELISA kits. The apoptotic rate of splenocytes was measured by FACsort. Meanwhile,BCG and PBS controls were set up for comparison. It was found that in the group of mice with plasmid DNA plL-12 immunization, rate of reduction in hydatid cyst weight was 44.85 %, the percentage of the splenic CD4^＋ and CD8^＋ T lymphocytes as well as the levels of IL-2,IFN-γ and TNF-α were obviously increased in comparison with those in the control groups of mice, however, the level of IL-4 showed a definite decrease. The apoptotic rate of splenocytes was also lower than that of the PBS control group of mice. It is concluded that the vaccination with plasmid DNA plL-12 can induce a protective immune response in mice against the hydatid cyst of E. granulosus.