信号肽与猪链球菌GDH融合的DNA疫苗构建及体液免疫研究

Construction of a DNA vaccine encoding GDH of Streptococcus suis and its humoral immune effects

目的设计、构建猪链球菌GDH真核表达载体并研究DNA疫苗免疫小鼠的体液免疫。方法在猪链球菌保护性抗原GDH基因5′末端引入人IL-2信号肽序列,通过PCR进行拼接,得到的融合DNA片段经过酶切克隆入质粒pcDNA3.0,构建核酸疫苗重组质粒pcDNA3.0-gdh。通过肌肉注射途径将重组质粒pcDNA3.0-gdh免疫小鼠,经ELASA实验和Western blot进行检验。结果构建的表达载体在小鼠体内表达出正确的目的蛋白,能诱导体液免疫。结论构建的DNA疫苗能够引起体液免疫,为研究猪链球菌核酸疫苗提供分子工具。

Objective To design and construct eukaryotic expression vector of Streptococcus suis GDH and to study the humoral immunity of the mice immunized with the DNA vaccine pcDNA3.0-gdh. Methods Human interleukin-2 （ID2） signal peptide was spliced to the 5＇ terminus of gdh gene of Streptococcus suis by overlap extension polymerase chain reaction （PCR）. The modified gdh gene was linked to plasmid pcDNA3.0 for constructing pcDNA3.0-gdh, which was also called DNA vaccine. Balb/c mice were vaccinated intramuscularly with the DNA vaccine every four weeks. After twice vaccination, polyclonal antibodies of the immunized mice were tested by indirect ELISA assay and western blotting assay. Results The sequencing results showed that pcDNA3.0-gdh was constructed successfully and pcDNA3.0-gdh could express the GDH protein which stimulates the immune response in mice. Conclusion The constructed plasmid pcDNA3.0-gdh could induce the immune response of mice, which will be a valuable molecular tool for studying the streptococcus suis DNA vaccine.