福氏2a志贺氏菌△aroA突变减毒株的构建  

Construction of a △aroA Attenuated Shigella flexneri 2a Strain

作　　者：刘英杰[1] 芮贤良[1] 徐永强[1] 赵海峰 苏国富[1] 黄翠芬[1] 

机构地区：[1]军事医学科学院生物工程研究所

出　　处：《中国生物化学与分子生物学报》1998年第5期542-546,共5页Chinese Journal of Biochemistry and Molecular Biology

摘　　要：志贺氏菌芳香族氨基酸合成酶基因缺陷能够使菌体明显减毒，并有可能成为新一代痢疾疫苗．用ＰＣＲ技术从野生型福氏２ａ志贺氏菌２４５７Ｔ中克隆出ａｒｏＡ基因，在体外进行精确的缺失突变，并通过体内同源重组，构建成△ａｒｏＡ突变体ＲＳ４２６．实验结果表明，这种突变体仍保持了侵袭能力和保护性Ｏ抗原的表达，但其毒力已明显降低，不能产生豚鼠角结膜炎，小鼠半数致死量明显提高．免疫保护试验显示，ＲＳ４２６可在小鼠中产生对福氏２ａ野生菌１００％的保护作用．Shigella spp can be appropriately attenuated by the aro gene mutation.The aro mutant may be used as a new generation anti Shigella candidate vaccine.The aroA gene of S.flexneri 2a 2457T was amplified by PCR and mutated by precise deletion of a middle of fragment of the aroA gene in vitro.The constructed △aroA gene was used to replace the wild type aroA gene of S.flexneri 2a 2457T by homologous recombination which resulted in the construction of a △aroA mutant RS426. Experimental results showed that this strain retained the ability of cell invasion and O antigen expression,but had been significantly attenuated,which was confirmed by its loss of the ability to provoke the keratoconjunctivits in guinea pigs and much higher LD 50 value in mice.Immune protection test demonstrated that RS426 could provide 100% protection against the challenge of virulent S.flexneri 2a in mice.

关 键 词：志贺氏痢疾杆菌 aroA基因 同源重组 减毒活菌苗 

分 类 号：Q78[生物学—分子生物学] R392.7[医药卫生—免疫学]