牛源金黄色葡萄球菌粘附因子Efb与ClfA的免疫生物学特性比较

Immunological comparison of Efb and ClfA of Staphylococcus aureus isolated from bovine

摘要:

为评价与比较金黄色葡萄球菌的粘附因子Efb (Extracellular fibrinogen-binding protein) 和ClfA (Clumping factor A) 的抗原性、粘附特性及其抗血清对金黄色葡萄球菌菌体的识别能力、抗粘附能力及免疫保护力等免疫生物学特性，分别构建Efb和ClfA的重组表达载体，并用纯化的重组蛋白免疫实验动物，分别检测家兔抗血清对菌体的识别能力、抗粘附能力以及小鼠抗血清的抗体效价和免疫保护作用。结果显示，Efb和ClfA 均有与纤维蛋白原 (Fibrinogen, Fg) 结合的能力，且Efb蛋白对纤连蛋白 (Fibronectin, Fn) 的结合能力优于ClfA (P＜0.01)，ClfA免疫组抗血清对全细菌的识别能力优于Efb免疫组(P＜0.01)。与对照组相比Efb和ClfA免疫组的抗血清均能显著抑制金黄色葡萄球菌对Fg和Fn的粘附(P＜0.01)，Efb免疫组对金黄色葡萄球菌的粘附抑制优于ClfA，两种粘附因子免疫小鼠后产生的血清抗体效价与对照组比较有显著的升高，抗体滴度可达1∶40 500，攻毒结果显示Efb与ClfA免疫组均对小鼠具有良好的保护效果。该研究结果对Efb在金黄色葡萄球菌的亚单位疫苗的应用奠定了基础。

Abstract:

To compare immunological characteristics of Extracellular fibrinogen-binding protein (Efb) and Clumping factor A (ClfA) of Staphylococcus aureus, we constructed two prokaryotic expression vector pET28a-Efb and pET28a-ClfA. After prokaryotical expression and purification, Efb and ClfA were used to immunize experimental animal. After the second immunization the antisera were collected and the antibody titers, the bacteria binding activity and adhesion inhibition activity of these antisera were detected by enzyme linked immunosorbent assay, adhesion inhibition assay and challenge. Both Efb and ClfA had Fibrinogen binding activity whereas the former had better Fibronectin binding activity. The bacteria binding capability of antisera of rabbits immunized with ClfA was better than that with Efb (P<0.01). Both antisera of Efb and ClfA could inhibit adherence activity of Staphylococcus aureus to Fibrinogen and Fibronectin adherence compare to the control group (P<0.01), and Efb had better adhesion inhibition activity than ClfA. The antibody titer of immunized group could reach 1:40 500. After the second immunization, both Efb and ClfA had good protective efficacy. This result constitutes a good foundation for Staphylococcus aureus subunit vaccine development.