摘要目的了解编码SAG1的重组质粒和IL-2基因佐剂在小鼠体内的免疫反应,评价该疫苗对弓形虫的保护作用.方法编码SAG1的质粒和鼠源性IL-2表达载体以100 μg的剂量免疫小鼠,3w后两次以相同的剂量加强免疫,分别以PBS和空质粒pcDNA3感染.采用ELISA法测定抗体水平、亚型、IFN-γ和I L-4的含量,PCR及原位杂交检测感染鼠中DNA的整合及降解.所有鼠均由强毒力RH株弓形虫感染.结果 SAG1表达质粒3次免疫后鼠体内特异IgG水平明显增高,IL-2表达质粒的联合使用导致IgG2a 水平升高和IFN-γ的产生.混合质闰注射的小鼠抗弓形虫感染的存活时间延长.结论由SAG1 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同注射对抵抗弓形虫感染有较好的效果.

abstractsObjective To characterize the immune response induced by SAG1 encoding plasmid combined with IL-2 gene adjuvant in mice and to assess the protective effect of this vaccination against toxoplasmosis.Methods Mice were co-injected intramuscularly with plasmid encoding Toxoplasma gondii SAG1 plus murine IL-2 expression vector at a d ose of 100 μg. Booster immunizations were employed 2 more times at 3-week in terval. As controls, mice were inoculated with PBS or empty plasmid pcDNA3. Hu moral and cellular responses were assayed using ELISA for the determination of Ab, Ab isotype and IFN-γ, as well as IL-4. To detect the integration and diss emination of DNA in the injected mice, PCR and in situ hybridization were perfor med. All mice were then infected with highly virulent RH tachyzoites of Toxopla sma gondii intraperitoneally.Results Significant increases in specific IgG levels were obser ved in mice after immunization three times with SAG1 expression plasmid. With r espect to the IgG isotype, co-inoculation of IL-2 expression plasmid enhanced the level of IgG2a and the production of IFN-γ. Challenging mice by vaccinat ing with combined plasmids with RH tachyzoites resulted in prolonged survival. Conclusion Humoral and cytokine responses elicited by SAG1 DNA immunization can be modulated by co-inoculation with IL-2 expression plasmid. The use of DNA vaccine in combination with an appropriate cytokine gene to prev ent T. gondii infection warrants further investigation.