大肠杆菌肠毒素的基因融合及其免疫原性的研究

The Gene Fusion of the Escherichia coli Enterotoxins and Study on the Immunogenicity of the Fusion Peptide

应用重组基因工程技术，将热敏肠毒素Ｂ亚基（ＬＴ－Ｂ）基因与含有部分前体的耐热肠毒素（ｐｒｏ－ＳＴ）基因融合在一起，构建了表达ＬＴ－Ｂ／ｐｒｏ－ＳＴ融合蛋白的重组质粒．该融合蛋白不仅保持结合神经节苷脂（ＧＭ１）的能力，而且具有热敏肠毒素和耐热肠毒素的抗原性．乳鼠实验证明，融合蛋白虽然含有野生耐热肠毒素，但不具耐热肠毒素的生物毒性．腹腔免疫和鼻饲免疫均能激发产生抗ＥＴＥＣ两种肠毒素的抗体．

A fusion protein,comprising the B subunit of the heat labile enterotoxin and a portion of the precursor to the heat stable enterotoxin of Escherichia coli, had been created by recombinant genetic techniques.The fusion peptide retained the ability to bind to GM1 ganglioside,and possessed ST antigenicity and LT antigenicity.Although the hybrid molecule carried the natural sequence of the heat stable enterotoxin,it was greatly attenuated in toxicity.More importantly,intraperitoneal immunization of mice or intransal administration of the fusion peptide elicited antibody responses against both classes of E.coli enterotoxin.