牛乳源金黄色葡萄球菌黏附素分子FnBPA不同功能区生物学活性的比较分析

Comparison and Analysis of the Biological Activity of Antiserum after Immunizing with Expressed Different Domains of Staphylococus aureus Adhesin FnBPA Isolated from Bovine Milk

旨在研究和比较牛乳源金黄色葡萄球菌黏附素分子A区(FnBPA-A)和BCD区(FnBPA-BCD)两个功能区重组蛋白质免疫后的生物学功能,并评价其作为抗原开展研制抗金黄色葡萄球菌疫苗的价值。利用原核表达载体pET-28a分别表达重组蛋白质FnBPA-A与FnBPA-BCD,比较二者的黏附特性,并用纯化后的重组蛋白质单独及联合免疫方式免疫新西兰白兔和小鼠,分析比较各组蛋白质诱导的特异性抗体抑制菌体及对纤维蛋白原(Fg)、纤维连接素(Fn)的结合能力,免疫小鼠抗体水平及对小鼠的免疫保护力。结果表明,两种重组蛋白质具有不同的黏附活性,联合免疫组产生的特异性抗体水平及与Fg、Fn的结合能力均较单独免疫组高。重组蛋白质FnBPA的A区及两种蛋白质联合免疫组特异性抗体水平,抗血清对金黄色葡萄球菌Fg,Fn黏附的抑制能力要优于BCD区。免疫小鼠攻毒结果显示各免疫组均对小鼠有良好的保护效果,其中FnBPA的A区蛋白质免疫保护率高于其他试验组。该研究的结果可为牛源金黄色葡萄球菌性的乳腺炎新型疫苗的优化设计与合理应用提供依据。

The aim of this study was to express FnBPA-A(A domain of fibrinogen-binding region A)and FnBPA-BCD(BCD domain of fibrinogen-binding region A different domains of FnBPA)of Staphylococcus aureus,and compare the adhesion inhibition activities of their antiserum for prevention of bovine mastitis caused by S.aureus.FnBPA-A and FnBPA-BCD encoding genes were cloned and inserted into pET-28 avector.Then the recombinant proteins were expressed and purified to immune Newzeland rabbits and mice.The adhesin binding ability,adhesion inhibition activity of their serum antibody and challenge protection ability were tested.The results showed that the antibody level,the binding ability to Fg and Fn and adhesion inhibition activity of FnBPA-A and FnBPA-BCD co-immunization group were better than that of single immunization groups.The mice antibody level of FnBPA-A immunization group and co-immunization group were better than that of FnBPA-BCD immunization group.In addition,FnBPA-A and co-immunization group showed better adhesion inhibition activity to Fg,FnBPA-BCD and co-immunization group showedbetter adhesion inhibition activity to Fn.The immunological protection result showed that each group had good protective effect and FnBPA-A immunization group was the best one.The results of this study may provide the basis for design of new vaccines of bovine mastitis caused by S.aureus.