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目的评价耐甲氧西林金黄色葡萄球菌(MRSA)候选疫苗抗原FnBPA活性片段的免疫原性以及其在抵抗耐甲氧西林金黄色葡萄球菌感染中的免疫保护作用。方法构建pGEX-6p-2-FnBPA表达载体,经可溶表达及亲和纯化后的重组蛋白免疫Balb/c小鼠。末次免疫后的第7天,分离免疫小鼠的血清ELISA检测IgG及其亚型抗体水平,同时测定体外抗体介导的调理吞噬作用。末次免疫后的第14天,经尾静脉感染ATCC国际标准株MRSA-252,统计分析感染后各组的小鼠的生存率以及检测脾脏,肾脏的细菌定植量。结果成功构建、表达及纯化了FnBPA活性片段,重组蛋白纯度可达90%;免疫后诱导小鼠机体产生了高效价的IgG抗体,并在体外能发挥抗体介导的调理吞噬作用;在感染保护评价实验中,与对照组相比,实验组的生存率显著提高(P<0.01),并显著降低了脾脏与肾脏的细菌定植量(P<0.05)。结论耐甲氧西林金黄色葡萄球菌重组亚单位疫苗FnBPA具有良好的免疫原性和免疫保护作用,可以作为MRSA疫苗研究的重要候选抗原。
Objective To evaluate the immunogenicity of the FnBPA-active fragment of methicillin-resistant Staphylococcus aureus (MRSA) candidate vaccine antigen and its immunological protection against methicillin-resistant Staphylococcus aureus infection. Methods The pGEX-6p-2-FnBPA expression vector was constructed and the Balb / c mice were immunized with the recombinant protein, which was soluble and affinity-purified. On the 7th day after the last immunization, the sera of immunized mice were tested for the levels of IgG and its subtype antibodies by ELISA and the in vitro antibody-mediated opsonophagocytosis. On the 14th day after the last immunization, the ATCC international standard strain MRSA-252 was infected through the tail vein. The survival rate of the mice in each group after infection and the colonization rate of the spleen and kidney were detected. Results The recombinant FnBPA fragment was successfully constructed, expressed and purified, and the purity of the recombinant protein was up to 90%. After immunization, the mice were induced to produce high titer IgG antibody and could play an antibody-mediated phagocytosis in vitro. In the evaluation experiment, the survival rate of the experimental group was significantly higher than that of the control group (P <0.01), and the bacterial colonization rate of the spleen and kidney was significantly decreased (P <0.05). Conclusion The methicillin-resistant Staphylococcus aureus recombinant subunit vaccine FnBPA has good immunogenicity and immunoprotection, and can be used as an important candidate antigen for MRSA vaccine research.