大肠埃希氏菌F18菌毛结构蛋白与黏附特性的关系

利用已表达的F18ab和F18ac菌毛各结构亚单位的融合蛋白(GST-FedA/ab、GST-Fe-dA/ac、GST-FedE、GST-FedF/ab、GST-FedF/ac)分组肌肉注射健康家兔,制备抗FedA/ab、Fe-dA/ac、FedE、FedF/ab、FedF/ac多价血清。结果表明,所制备的5种抗Fed多价血清均能凝集F18ab 大肠埃希氏菌107/86株和F18ac 大肠埃希氏菌8813株。利用抗大肠埃希氏菌F18菌毛主要结构亚单位FedA特异抗体和次要结构亚单位FedE、FedF特异抗体,研究了F18菌毛与小肠上皮细胞的黏附特性。结果发现,FedA抗体和FedE抗体单独和合并均不能抑制F18 菌与小肠上皮细胞的黏附,而单用抗FedF抗体即能明显抑制F18 大肠埃希氏菌与小肠上皮细胞的黏附,表明FedA和FedE与F18菌毛的黏附不具相关性,而FedF才是F18菌毛的黏附性结构亚单位。

Correlation between functional adherence and subunits of Escherichia coli fimbriae F18

Five kinds of recombinant proteins GST-FedA/ab, GST-FedA/ac, GST-FedE GST- FedF/ab and GST-FedF/ac, were extracted by SDS-PAGE method. Five groups of healthy rabbits were immunized with the 5 recombinant proteins respectively and anti-FedA/ab, anti-FedA/ac, anti-FedE anti-FedF/ab and anti-FedF/ac were obtained. The results of the direct agglutination test of the 5 kinds of antisera by using F18ac-positive Escherichia coli 107/86 and F18ac-positive E.coli 8813 respectively showed that all the 5 kinds of antisera could recognize F18ab and F18ac. To investigate the relationship of subunit(s) of F18 fimbrial adhesin with the adhesion effect, adhesive inhibition tests were performed using antibodies specific for the subunits FedA, FedE and FedF. The results showed that anti-FedA and/or anti-FedE (serum) was unable to inhibit adhesion of F18~( ) E.coli to porcine enterocytes, whereas anti-FedF antibody could overtly inhibit the adhesion, which showed the FedF is the adhesive subunit of F18 fimbriae.