| 摘要: |
| 为探究金黄色葡萄球菌超抗原样蛋白(Staphylococcal superantigen-like proteins，SSLs)与补体系统相关的生物学特征，利用原核表达系统表达SSL7重组蛋白，并通过补体杀伤试验、Western Blot以及Pull-down对其有关补体系统的生物学特征进行研究。结果表明:1)重组蛋白SSL7可在大肠杆菌感受态细胞BL21(DE3)系统中大量可溶性表达，大小约25 ku；2)SSL7可阻断新鲜兔血清对大肠杆菌DH5α的补体杀伤作用；3)SSL7抑制补体激活后攻膜复合体(Membrane attack complex，MAC)的形成，新鲜兔血清无法在金黄色葡萄球菌NCTC 8325菌体表面形成MAC沉积；4)SSL7能捕获健康人血清(Human normal serum，HNS)中的补体C5，阻断补体系统的激活。综上，金黄色葡萄球菌超抗原样蛋白SSL7可以通过特异性结合补体C5阻断补体级联反应，逃避宿主免疫应答以达到致病的目的，为进一步探究SSL7的感染机制、揭示SSLs蛋白功能奠定基础。 |
| 关键词: 金黄色葡萄球菌 SSL7蛋白 补体系统 |
| DOI：10.11841/j.issn.1007-4333.2021.09.16 |
| 投稿时间：2020-11-17 |
| 基金项目:现代农业(奶牛)产业技术体系建设专项资金(CARS-36) |
|
| Effects of Staphylococcus aureus SSL7 protein on complement system |
|
DENG Yining,ZHANG Yunke,WANG Pengpeng,TIAN Xinrui,JIAO Xiaoyu,WU Wenxue
|
| (College of Veterinary Medicine, China Agricultural University, Beijing 100193, China) |
| Abstract: |
| To explore the biological features of Staphylococcal superantigen-like proteins(SSLs)related to complement system, the recombinant protein SSL7 was expressed by prokaryotic expression system and the biological characteristics of SSL7 associated with complement system were studied by complement killing test, Western blot, and Pull-down analyse. The results showed that: 1)The recombinant SSL7 could be expressed soluble in E. coli competent cell BL21(DE3)in a large amount with a size of about 25 ku; 2)SSL7 blocked the complement killing effect of fresh rabbit serum on E. coli DH5α; 3)SSL7 inhibited the formation of membrane attack complex(MAC). Fresh rabbit serum lost the ability to form MAC deposition on the surface of S. aureus NCTC 8325; 4)SSL7 intercepted the activation of complement system via capturing complement C5 in human normal serum. In a nutshell, SSL7 is capable to block the cascade reaction by specifically binding complement C5, evade the host immune response to achieve the purpose of pathogenicity, which lays the foundation for further exploring the infection mechanism of SSL7 and revealing the function of SSLs. |
| Key words: Staphylococcus aureus SSL7 complement system |
