Peng Gao-Hui, Yuan Zi-Guo, Zhou Dong-Hui, He Xian-Hui, Liu Miao-Miao, Yan Chao, Yin Chuang-Cheng, He Yong, Lin Rui-Qing, Zhu Xing-Quan
Department of Parasitology, College of Veterinary Medicine, South China Agricultural University, 483 Wushan Street, Tianhe District, Guangzhou, Guangdong Province 510642, People's Republic of China.
Vaccine. 2009 Nov 5;27(47):6570-4. doi: 10.1016/j.vaccine.2009.08.043. Epub 2009 Aug 29.
Infection with the intracellular protozoan parasite Toxoplasma gondii causes serious public health problems and is of great economic importance worldwide. Microneme proteins which are responsible for adhesion and invasion have been implicated as vaccine candidates. In this study, we constructed a DNA vaccine expressing microneme protein 6 (MIC6) of T. gondii, and evaluated the immune response it induced in Kunming mice. The gene sequence encoding MIC6 was inserted into the eukaryotic expression vector pVAXI. We immunized Kunming mice intramuscularly. After immunization, we evaluated the immune response using lymphoproliferative assay, cytokine and antibody measurements, and the survival times of mice challenged lethally. The results showed that the group immunized with pVAX-MIC6 developed a high level of specific antibody responses against T. gondii lysate antigen (TLA), a strong lymphoproliferative response, and significant levels of IFN-gamma, IL-2, IL-4 and IL-10 production, compared with the other groups immunized with empty plasmid or phosphate-buffered saline, respectively. These results demonstrate that pVAX-MIC6 induces significant humoral and cellular Th1 immune responses. After lethal challenge, the mice immunized with the pVAX-MIC6 showed an increased survival time (13.3+/-1.2 days) compared with control mice died within 7 days of challenge. Our data demonstrate, for the first time, that MIC6 triggered a strong humoral and cellular response against T. gondii, and that the antigen is a potential vaccine candidate against toxoplasmosis, worth further development.
细胞内原生动物寄生虫刚地弓形虫感染会引发严重的公共卫生问题，在全球具有重大经济意义。负责黏附和侵袭的微线体蛋白被认为是疫苗候选物。在本研究中，我们构建了一种表达刚地弓形虫微线体蛋白6（MIC6）的DNA疫苗，并评估了其在昆明小鼠中诱导的免疫反应。将编码MIC6的基因序列插入真核表达载体pVAXI中。我们通过肌肉注射免疫昆明小鼠。免疫后，我们使用淋巴细胞增殖试验、细胞因子和抗体检测以及对致死性攻击小鼠的存活时间评估免疫反应。结果显示，与分别用空质粒或磷酸盐缓冲盐水免疫的其他组相比，用pVAX-MIC6免疫的组对刚地弓形虫裂解物抗原（TLA）产生了高水平的特异性抗体反应、强烈的淋巴细胞增殖反应以及显著水平的干扰素-γ、白细胞介素-2、白细胞介素-4和白细胞介素-10产生。这些结果表明pVAX-MIC6诱导了显著的体液和细胞Th1免疫反应。在致死性攻击后，用pVAX-MIC6免疫的小鼠与在攻击后7天内死亡的对照小鼠相比，存活时间延长（13.3±1.2天）。我们的数据首次证明，MIC6引发了针对刚地弓形虫的强烈体液和细胞反应，并且该抗原是一种潜在的抗弓形虫病疫苗候选物，值得进一步开发。
