肠毒素大肠杆菌定居因子抗原基因CFA-I在痢疾杆菌中的表达

摘要

A host-plasmid lethal balancing system was constructed based onasd gene in an avirulent strain of S. flexneri to express colonization factor antigen I(CFA-I) of enterotoxigenic Escherichia coli. The results of Western blotting suggested that avirulant strain of S. flexneri Fwl01 expressed CFA-I steadily. Examination of negatively-stained preparation of cultures by electron microscopy showed that S. flexneri Fwl01 carrying the plasmid pZHY21 had thick pili on its surface. Antibodies against CFA-I were deeteted in sera of mice immunized with recombinant bacteria either orogastrically (o. g. ) or intranasally(i.n.); simultaneously slgA against CFA-I was also decteted in the intestine. This work is helpful for constructing multivalent reombinant vaccine for prevention of bacterial diarrhea.%通过体外重组的方法，构建了包含asd基因的重组表达质粒pZHY21，与福氏志贺氏菌Fwl01构成了宿主-载体平衡致死系统，Western印迹结果表明，在没有抗生素条件选择的情况下，稳定表达肠毒素大肠杆菌定居因子抗原CFA-I。电镜结果显示，在重组菌株的菌体表面，表达产物能够装配成菌毛。重组菌通过口服和鼻饲免疫小鼠后，可以诱生CFA-I的抗体；同时可以检测到分泌型IgA产生，表明重组菌可以诱导相应的粘膜免疫反应。