泛素-结核抗原融合基因DNA疫苗诱导的小鼠细胞免疫应答

Cellular immune response induced by ubiquitin and Ag85A antigen fusion gene DNA vaccine in mice

目的 构建结核杆菌Ag85A抗原DNA疫苗（pA）和泛素基因与Ag85A抗原基因融合的DNA疫苗（pUA）,观察疫苗在小鼠中的免疫应答.方法 将构建的DNA疫苗pA和pUA分别肌肉注射免疫BALB/c雌性小鼠,检测小鼠的血清抗体（IgG、IgG1、IgG2a）、细胞因子（IFN-γ、IL-4）和细胞毒性T淋巴细胞反应,比较融合基因DNA疫苗和单基因DNA疫苗诱导的免疫应答的强度.结果 pA组小鼠血清IgG水平高于pUA组（P＜0.01）,但IgG2a/IgG1比值（4.16±0.20）低于pUA组（7.88±0.30）（P＜0.01）.与pA组比较,pUA组小鼠IFN-γ分泌水平增高（P＜0.01）,IL-4分泌水平下降（P＜0.01）;pUA组的CTL活性高于pA组.结论 融合的DNA疫苗pUA诱生的抗原特异的体液免疫应答不及单基因DNA疫苗pA,但其能诱导更强的细胞免疫应答.提示泛素-Ag85A融合基因DNA疫苗对于防治结核病比单基因DNA疫苗更为有效.

Objective To evaluate the immune response induced by ubiquitin-Ag85A fused DNA vaccines （pUA）. Methods Constructed DNA vaccines were intramuscularly inoculated into female BALB/c mice respectively. Serum antibodies （including IgG,IgG1,IgG2a）,cytokines （IFN-γ,IL-4） and cytotoxic T lymphocyte response were detected in mice. The immune response intensity induced by fusion gene DNA vaccine and monogenic DNA vaccine was also compared. Results IgG level in the pA group was higher than that in the pUA group（P 〈0. 01 ）,nevertheless,the ratio of IgG2a/IgG1 in the pA group was lower than that of the pUA group[（4. 16 ±0. 20）vs （7. 88 ± 0. 30 ）,P 〈 0. 01 ]. IFN-γ level increased （P 〈 0. 01 ） and the IL-4 level decreased （P 〈 0. 01 ） in the pUA group,when compared with those of the pA group. Furthermore,Ubiquitin fusion DNA vaccine enhanced the activity of CTL. Conclusions Results showed that humoral immune response induced by the fusion gene DNA vaccines was weaker than that by the monogenic DNA vaocine,however,stronger cellular immune response could be induced,when compared with the non-fusion DNA vaccine. Our study indicated that the ubiquitin fused DNA vaccine was more effective than the monogenic DNA vaccine in the prevention and treatment of tuberculosis.