弓形虫表面抗原SAG3基因和IL-2基因佐剂混合诱导小鼠免疫应答研究  

Induction of immune responses in mice by the combined use of the recombinant plasmid encoding the surface antigen SAG3 of Toxoplasma gondii and the IL-2 gene adjuvant

作　　者：周永安[1] 余新炳[1] 陈海峰 郑焕钦[1] 殷国荣[3] 吴忠道[1] 陈观今[1] 

机构地区：[1]中山大学中山医学院病原生物学部,广州510089 [2]Biological Sciences Department State University of New York [3]山西医科大学寄生虫学教研室,太原030001

出　　处：《中国人兽共患病杂志》2005年第11期945-948,共4页Chinese Journal of Zoonoses

基　　金：国家自然科学基金(NO.30070682);"211工程"重点学科建设基金;广东省首批自然科学团队基金资助

摘　　要：目的了解编码SAG3的重组质粒和IL-2基因佐剂在小鼠体内的免疫反应,为进一步的核酸疫苗及免疫学研究创造条件。方法将编码SAG3的质粒和鼠源性IL-2表达载体以100μg的剂量感染小鼠,3周中两次以相同的剂量加强免疫,分别以PBS和空质粒pcDNA3.1感染。采用ELISA法测定抗体水平、亚型、IFN-γI、L-4和IL-2的含量,RT-PCR方法检测注射部位目的基因的转录,所有鼠均由强毒力ZS2株弓形虫感染。结果SAG3表达质粒3次免疫后鼠体内特异IgG水平明显上升,IL-2表达质粒的联合使用导致IgG2a水平的升高和IFN-γ的产生,提高了其分泌IL-2的水平,但对IL-4的水平产生轻微的影响;RT-PCR显示首次使用导致IgG2a水平的升高和IFN-γ的产生,提高了其分泌IL-2的水平,但对IL-4的水平产生轻微的影响;RT-PCR显示首次免疫15天后,目的基因在肌肉组织中仍有表达;混合质粒注射和小鼠抗弓形虫感染的存活时间延长。结论由SAG3 DNA诱导的免疫应答因IL-2表达质粒的共同注射而增强,DNA疫苗和适当细胞因子的共注射对抵抗弓形虫感染的效果值得进一步研究。Mice were co-injected intrtamuscularly with the recombinant plasmid encoding the surface antigen SAG3 of Toxoplasma gondii plus murine expression vector for IL-2 at the dosage of 100μg. Booster immunizations were performed with the same doses 2 times at 3 weeks interval. As controls mice were inoculated with PBS and the empty plasmid pcDNA3.1 respectively. ELISA assay was employed todetermine antibody levels, antibody isotypes and the amounts of IFN-γ, IL-4 and IL-2; and PT-PCR was used to evaluate the transcription of the inoculated target DNA complex in injected sites. All mice were conducted to be challenged with the tachyzoites of highly virulent strain ZS2 of T. gondii through the intraperitoneal route. It was found that significant specific IgG level could be detected in mice after three immunizations by the expression plasmid with SAG3. In respect to the IgG isotypes, co-inoculation with the expression plasmid with IL-2 enhanced the level of IgG2a and the production of IFN-γ. As demonstrated by RT-PCR, the duration of the transcribed DNA inoculated in the injected muscular tissues was at least 15 days after the first inoculation. The survival time of mice after immunization with the combined plasmids after challenging with the ZS2 tachyzoites was prolonged. It is concluded from the results of the present study that the immune responses induced by the combined use of the recombinant plasmid encoding SAG3 of T. gondii and the IL-2 gene adjuvant can be enhanced.

关 键 词：DNA免疫 弓形虫表面抗原SAG3 基因佐剂 免疫应答 

分 类 号：R382.5[医药卫生—医学寄生虫学]