金黄色葡萄球菌凝集因子A的免疫原性

Immunogenicity of Staphylococcus aureus recombinant clumping factor A

摘要:

为研究金黄色葡萄球菌(Staphylococcus aureus)凝集因子A(ClfA)免疫原性及免疫保护作用, 应用PCR方法扩增出金黄色葡萄球菌 Newman、Wood46和HLJ23-1株的clfa基因并进行序列分析, 再将Newman株的clfa基因插入到pQE-30载体上, 导入宿主菌Escherichia coli M15 (pREP4)并诱导表达和纯化ClfA重组蛋白。用纯化的ClfA免疫小鼠, 检测血清中抗体和细胞因子水平, 首次免疫后35 d时用金黄色葡萄球菌 Wood46、HLJ23-1、Newman株对小鼠攻毒。结果发现: clfa基因序列高度保守; ClfA重组蛋白在E. coli M15中获得表达; 在首次免疫后35 d时血清抗体效价和细胞因子浓度与对照组相比, 均显著升高(P < 0.05); 攻毒结果为蛋白免疫组小鼠获得一定的免疫保护。由此表明, ClfA重组蛋白有较好的免疫原性和免疫保护力。

Abstract:

In order to characterize the immunogenicity and immunoprotection of the Staphylococcus aureus (S. aureus) surface protein Clumping factor A (ClfA), we amplified clfa genes from S. aureus Newman strain, Wood46 strain and HLJ23-1. The clfa gene from Newman strain was subsequently inserted into pQE-30 vector and the recombinant plasmid was transformed into Escherichia coli strain M15 (pREP4). The recombinant ClfA protein was expressed and purified. Then, we immunized mice with the purified recombinant protein. The antibody level and the concentration of cytokines were measured by enzyme-linked immunosorbent assay. Finally, immunized mice were challenged with S. aureus Newman, Wood46 and HLJ23-1. These results suggested that clfa gene sequences were highly conserved, and the recombinant ClfA was expressed correctly with good antigenicity. The antibody titer and the concentration of cytokines in the immunized groups increased significantly (P<0.05) compared with control, and the mice in the immunized groups were protected against the challenge strains to some extent. These results showed that the ClfA had high immunogenicity and immunoprotective potential.