假结核耶尔森菌侵染素蛋白作为DNA疫苗佐剂的免疫效果

目的探讨假结核耶尔森菌侵染素(invasin)羧基端397个氨基酸(Inv397)对抗原免疫原性的影响,以评价其作为DNA疫苗佐剂的效果。方法利用PCR扩增Inv397编码基因(inv397),分别构建编码猪丹毒丝菌表面抗原氨基端蛋白(spaA-N)和Inv397蛋白的重组真核表达质粒pcDNA3.1-spaA-N,pcDNA3.1-spaA-N-inv397。同时构建重组载体pET-30a-inv397,并在大肠杆菌BL21中诱导表达,经过Ni Sepharose 6 Fast Flow亲和层析纯化重组Inv397蛋白。将纯化后重组Inv397蛋白与包含spaA-N的重组真核质粒滴鼻免疫ICR小鼠,ELISA法检测血清特异性抗体水平,细胞增殖实验分析T淋巴细胞增殖反应。结果 Inv397蛋白与spaA-N重组质粒滴鼻免疫组的血清spaA-N特异性IgG水平明显高于spaA-N其它对照组(P<0.01),且T细胞增殖水平也高于其他各组,但无显著差异。结论 Inv397蛋白具有一定程度的免疫增强作用,有可能成为一种新的DNA疫苗佐剂。

The adjuvanticity of Yersinia Pseudotuberculosi invasion complex with DNA vaccines

The invasin derived from Yersinia Pseudotuberculosi can efficiently aid the foreign antigens to enter APC cells and might enhance antigen specific immune response.To evaluate the potential of invasin as effective adjuvant in DNA based immunization,we constructed different pcDNA3.1 recombinant plasmids comprising N-terminal of surface protective antigen A(spaA-N) from Erysipelothrix rhusiopathiae combined with C-terminal 397 amino acids of invasion(Inv397) from Yersinia pseudotuberculosi,and then intranasally immunized the ICR mice with or without Inv397 recombinant protein to detect humoral and cellular immune response by ELISA and T lymphocyte proliferative assay.The ELISA results showed that the levels of spaA-N-specific IgG in the mice co-immunized with pcDNA3.1-spaA-N plasmid or pcDNA3.1-spaA-N-inv397 and Inv397 protein were significant higher than that of mice immunized without Inv397 protein(P<0.01).T lymphocyte proliferative assay showed the stimulation index of co-immunization group was not significant high as compared with other groups.The results suggested Inv397 protein can enhance the humoral response in this study and may have the potential to be used as an adjuvant in DNA vaccine.