缺失rfaH基因的鸡白痢沙门氏菌株的构建及鉴定

Construction of the rfaH gene delated Salmonella pullorum

为研制可以鉴别检测基因缺失型鸡白痢疫苗与自然感染菌,本研究通过基因同源重组技术,利用高效自杀性载体系统,敲除鸡白痢沙门氏菌(S.pullorum)CVCC 79201株的rfaH基因,同时未引入任何抗生素抗性基因等外源DNA序列,经筛选获得重组S.pullorum(rSp)株。检测结果显示缺失菌由光滑型转变为粗糙型。rSp在普通琼脂培养基上传15代后,仍然保持粗糙型表型。动物试验结果表明,rSp免疫伊莎褐蛋鸡后,其抗血清可通过平板凝集试验与CVCC 79201免疫的血清相区分。本研究为S.pullorum缺失疫苗的研制提供了技术平台。

Vaccination against Salmonella pullorum in chicken has not been widely used,because of the difficulties in the discrimination between infected and vaccinated animals.In order to obtain a S.pullorum vaccine with no interference to quarantine procedures,the rfaH gene from S.pullorum CVCC 79201 strain was knocked out by homologous recombination utilizing high performance suicide vector system to generate recombinant S.pullorum rSp strain.rfaH delation converted S.pullorum into rough-phenotype from smooth-phenotype,which remained stable after 15 passages in common nutrient agar.Serum collected from rSp immunized Isa Brown Chicken could be differentiated from serum collected from CVCC 79201 immunized chicken.In view of these results,rSp could be a promising candidate for vaccine development.