信号肽和辅助性T细胞表位以及GST表位增强猪带绦虫保护性抗原诱导免疫应答的初步研究

Enhancement of immune responses of pCC27 DNA vaccine by a signal peptide and a universal helper T lymphocyte epitope and two GST epitopes

目的 研究信号肽和辅助性T细胞表位以及GST表位增强猪带绦虫保护性抗原诱导的免疫应答。方法 在猪绦虫融合抗原 pCC2 7(本室从六钩蚴cDNA表达文库筛选的三个保护性抗原经拼接所得 )基因片段 5′末端引入人IL - 2信号肽、一个通用型辅助性T淋巴细胞表位 ,谷胱甘肽还原酶的T和B淋巴细胞表位 (TGG) ,经pGEX4T - 2表达鉴定 ,序列分析后构建成DNA疫苗 ,通过肌肉注射途径将这种DNA疫苗免疫小鼠。结果 这种含辅助表位的DNA疫苗诱导的免疫应答效果明显超过对照组 ,对绦虫卵攻击的保护率为 90 %。结论 构建了含绦虫融合抗原 pCC2 7及TGG的核酸疫苗 ,动物试验结果表明 ,TGG表位既可提高IgG、IgG1、IgG2a的水平 ,又进一步增强Th1和Th2细胞间的平衡关系。免疫小鼠对绦虫卵的攻击具有很好的保护作用。

Aim The human interleukin-2 singal peptide,a universal helper T lymphocyte epitope and two GST epitopes were spliced to the 5' end of pCC27 fusion gene in order to modulate the balance of Th1/Th2 and enhance the immune efficiency.Methods The modified pCC27 fusion gene was used to construct a DNA vaccine.BALB/c mice were vaccinated intramuscularly with the modified pCC27 DNA vaccine and the unmodified pCC27 DNA vaccine.Serum antibodies IgG2a/IgG1 of the immunized mice were measured by ELISA.Results A recombinant plasmid pGEX4T-STGG which can express GST-STGG fusion protein in E.coli TH1 has been successfully constructed.The animal test showed that 90% of mice immunized with the modified DNA vaccine pVAX-STGG-CC27 were protected against the challenge infection with Cysticercus Cellulosae and this was paralleled by an increased level of IgG and more importantly,of IgG2a,IgG1 pCC27-specific antibodies.Conclusion The modified DNA vaccine pVAX-STGG-CC27 induced humoral immune responses much stronger in vivo than the unmodified DNA vaccine pVAX-CC27.Mice immunized with this modified DNA vaccine pVAX-STGG-CC27 could defend themselves well from the attack of Cysticercus Cellulosae.