染色体整合系统在多价疫苗构建中的应用研究

A Chromosomal Integration System for Development of Polyvalent Vaccine Strains

通过同源重组将编码异源抗原的DNA整合到减毒的鼠伤寒沙门氏菌的染色体上，获得了表达霍乱毒素B亚单位（CTB）的双价活疫苗候选株。该系统包括两个步骤：首先将GisOG缺失突变的DNA片段整合进鼠伤寒沙门氏菌疫苗候选株SL3261的染色体上，得到His营养缺陷型。然后，用带有CTB抗原基因的完整HisOGDNA片段置换HisOG缺失的DNA片段，获得表达CTB的His回复的SL3261菌株（命名为TT201）。Southern杂交证明，TT201菌株的染色体带有CTB抗原基因。Westernblot分析表明，TT201菌株能表达CTB，且具有很好的稳定性。用重组菌株口服免疫接种小鼠，能够激发抗CTB抗体的产生。TT201菌株是一种潜在的双价疫苗候选株。

We have developed a potential bivalent vaccine stain through the chromosomalintogration systom in which the gene that codes for the B subunit of cholera toxinwas integrated into the chromosome of an attenuated strain of Salmonella typhimurium.This system involves two steps: construction of a hisOG deletion mutation into thechromosome of S. typhimurium strain SL3261: and replacement of the hisOG deletionby the complete hisOG region and the segment of heterologous DNA which codes forthe B subunit of cholera toxin. The recombinant strain SL3261 (named TT201) wasobtained. Southern hybrid confirmed that the CTB gene was integrated into thechromosome of TT201. Western blot analysis demonstrated that the CTB gene wasexpressed stably in TT201. When administered orally to mice, the recombinant strainelicited a serum antibody response to CTB. The stain TT201 is a potentially bivalentvaccine candidate.