金黄色葡萄球菌黏附素ClfA等抗体抑制该菌黏附牛乳腺上皮细胞效果的比较

Adhesive inhibition comparison of Staphylococcus aureus to bovine mammary epithelial cells by antibodies against 3 different adhesins

摘要:

[目的]为从免疫的角度比较和分析黏附素分子细胞外纤维蛋白原结合蛋白（Extracellular fibrinogen-binding protein，EfB）和纤维连接蛋白结合蛋A （Fibronection binding protein，FnBP）对聚集因子A （Clumping factor A，ClfA）抑制牛源金黄色葡萄球菌（Staphylococcus aureus，SA）黏附牛乳腺原代上皮细胞作用的增强效果。[方法]本试验分离培养牛乳腺上皮细胞并鉴定；将真核重组质粒EfB和FnBPA分别与ClfA组合免疫新西兰大白兔，并利用免疫后抗体体外抑制2株SA分离株侵染牛乳腺上皮细胞，采用平板计数法定量检测与比较不同免疫组合诱导抗体对黏附的抑制作用；对SA和乳腺上皮细胞分别进行荧光染色，观察不同免疫组合诱导的抗体对黏附抑制效果的差异。[结果]成功分离培养了牛乳腺原代上皮细胞；证明了构建的ClfA、FnBPA和EfB真核重组表达质粒均可在细胞中表达，且在免疫实验兔后可诱导特异性抗体的产生；细菌平板计数和荧光染色观察的结果表明，黏附素分子单独和组合免疫的抗体对该菌不同菌株（GY278和GY309）的黏附抑制能力不同，ClfA抗体的黏附抑制能力最强，FnBPA分子A区的黏附抑制能力优于D区。FnBPA、EfB分别与ClfA联合免疫抗体对黏附的抑制程度高于黏附素分子单独免疫组，FnBPA分子A区对ClfA黏附抑制的增强作用优于D区，FnBPA-A区与Efb相比对ClfA的黏附抑制增强差异不显著。[结论]FnBPA-A、FnBPA-D和EfB分别与ClfA联合免疫可不同程度地影响ClfA的黏附抑制效果，该结果为以黏附素分子为靶点的牛乳腺炎疫苗的研究提供了实验数据。

Abstract:

[Objective] To compare the inhibition effects of antibodies against extracellular fibrinogen-binding protein (EfB) and fibronection binding protein (FnBPA) to clumping factor A (ClfA) of Staphylococcus aureus (SA) to bovine mammary epithelial cells (bMEC) by immunization method.[Methods] The antibodies were obtained by immunizing rabbits with the recombinant plasmids Efb or FnBPA in-combination with ClfA. The antibodies inhibition effects on adereing of 2 SA strains to bMEC were tested using plate counting method and observed by fluorescent staining of SA and bMEC, respectively.[Results] Our results indicated that the antibodies had different inhibition effects on adhesion of SA (GY278 and GY309). ClfA antibody showed the highest inhibition ability. FnBPA-A showed greater inhibition enhancement to ClfA than FnBPA-D.[Conclusion] The in-combination immunization of FnBPA-A, FnBPA-D and EfB with ClfA could affect the antibodies inhibition to various degrees and this result provided experiment basis for the development of bovine mastitis vaccine.