外源抗原表位在大肠杆菌CS3菌毛上的呈现

Surface Display of Foreign Epitopes in the CS3 Pili of E.coli

为了探讨CS3菌毛多位点用于外源表位呈现以及重组蛋白的免疫原性 ,通过对CS3亚基蛋白二级结构、抗原表位、亲水性及柔韧性的预测分析 ,找出了两个新的插入位点 72位和 136位 ,将口蹄疫病毒VP1、脊髓灰质炎病毒C3等多种表位插入到CS3中 ,全细胞ELISA、免疫荧光检测和电镜观察等均表明外源表位在大肠杆菌表面得到了表达 ,而且 72位表达水平明显高于 136位。用重组菌腹腔注射免疫小鼠 ,可诱发机体产生针对CS3和外源表位的双重免疫应答。以上结果表明 ,CS3上有多个位点可实现外源表位的表面呈现 ,可望成为研制多价基因工程活菌疫苗的表达载体。

In order to study the possibility of inserting foreign antigenic epitopes into CS3 pili in diffenrent sites, the CS3 subunit protein was predicted. Based on the prediction, two sites,No.72 and No.136, were selected to insert foreign epitopes. Epitopes such as VP1 of the foot mouth disease virus and the C3 epitope of poliovirus were inserted into CS3 pili. The results of whole cell ELISA, immunofluorescence and electron microscopy showed they were displayed on the surface of the recombinant cells. Mice were immunized by injecting the recombinant bacteria intraperitoneally to evaluate the immunogenicity of the hybrid proteins. The result showed that mice could produce antibody response against CS3 and the foreign epitopes. All in above indicted CS3 can surface display the foreign epitopes in multiple sites, and it may probably become an expression vector for the construction of the live gene engeneering vaccine especially multi covalent vaccine.