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最近鉴定的大肠杆菌O157∶H7Ⅳ型菌毛(HCP)与细菌粘附、定植和致病有着密切关系。本文研究表明,PCR扩增出15个大肠杆菌O157∶H7分离株HcpA基因,透射电镜观察到HCP表达于菌体表面。同时,构建BL21(pET32-hc-pA)重组菌,成功表达重组蛋白His-HcpA。His-HcpA免疫家兔制备高滴度(1∶12800)多克隆抗体,Western blot显示能够与HCP菌毛蛋白反应。Balb/c小鼠分别在0周和第3周皮下接种His-HcpA,和对照组小鼠相比,获得70%存活率,并且排菌量降低,排菌时间缩短。本研究表明,His-HcpA具有良好的免疫原性,是大肠杆菌O157∶H7重要的毒力因子。
Recently identified E. coli O157: H7 type pili (HCP) is closely related to bacterial adhesion, colonization and pathogenicity. In this study, 15 HcpA genes of E. coli O157: H7 were amplified by PCR, and the HCP expression was observed by transmission electron microscopy. At the same time, BL21 (pET32-hc-pA) recombinant strain was constructed and the recombinant protein His-HcpA was successfully expressed. High-titer (1: 12800) polyclonal antibodies were prepared from His-HcpA-immunized rabbits and Western blotting showed that they reacted with HCP pilin. Balb / c mice were inoculated with His-HcpA subcutaneously at week 0 and week 3, respectively. Compared with the control group, the survival rate of the mice was 70%, the amount of inoculated bacteria was reduced and the time for arranging bacteria was shortened. This study shows that His-HcpA has good immunogenicity and is an important virulence factor of E. coli O157: H7.