表达大肠杆菌肠毒素ST_1-LT_B融合蛋白双价基因工程菌株的构建

Construction of Genetically Engineered Strain Expressing Escherichia Coli Heta stable Enterotoxin I and Heat labile Enterotoxin B Subunit Fusion Protein

重组菌株ＢＬ２１（ＤＥ３）（ｐＸＥＴＳＬＴ１）经ＩＰＴＧ诱导后，其表达产物经ＳＤＳ－ＰＡＧＥ和ＥＬＩＳＡ检测，结果表明重组菌株可以高效表达大肠杆菌肠毒素ＳＴ１－ＬＴＢ 融合蛋白，该融合蛋白占菌体总蛋白的３３．２１％ ，而且已失去天然ＳＴ１肠毒素生物毒性。用从ＩＰＴＧ 诱导的工程菌中提取的包涵体或经甲醛灭活的工程菌制成抗原免疫小鼠，结果免疫小鼠至少能抵抗１．５ＭＬＤ 的大肠杆菌强毒株Ｃ８３９０２（Ｋ８８ａｃ，ＳＴ＋ ，ＬＴ＋ ）的攻击。用提取的包涵体免疫家兔后，采集的血清能够中和天然ＳＴ１肠毒素的毒性。

The recombinant strain BL21(DE3) can produce nontoxic ST 1 LT B fusion protein.Being induced by IPTG,the expressed product was about 33.21% of total cellular protein.Mice immunized with the crude inclusion bodies containing ST 1 LT B fusion protein or inactivated recombinant strain produced antibodies that were able to protect the mouse against the challenge of at least 1.5 MLD dose of Escherichia coli C83902.Rabbit immunized with the crude inclusion bodies produced antibodies to neutralize the biological activity of native ST 1 enterotoxin in the suckling mouse assay.Hence,the authors,suggested that the recombinant strain BL21(DE3)(pXETSLT1)may be used as a candidate of vaccine strain.