crp缺失对猪霍乱沙门氏菌强弱毒株毒力的影响

猪霍乱沙门氏菌C500株是用化学方法将强毒株C78-1致弱,用于预防仔猪副伤寒的弱毒疫苗株,虽具有较好的免疫原性,但仍有一定的残余毒力。SC-1是临床分离的猪霍乱沙门氏菌强毒株。为了研制更加安全的弱毒株,利用重组自杀性质粒通过接合转移的方法构建了猪霍乱沙门氏菌C500株、C78-1及SC-1的crp缺失株。C78-1、crp-C78-1、SC-1、crp-SC-1、C500、crp-C500 6个毒株经小鼠毒力试验检测。LD50结果显示,crp缺失对猪霍乱沙门氏菌的毒力影响不大,毒力只是略为降低,其中以crp-C500株毒力最弱。综上所述,可以选用crp-C500株毒株作为猪霍乱沙门氏菌弱毒疫苗株的选择。

Effects of crp Deletion on the Virulence of Virulent and Attenuated Strains of Salmonella choleraesuis

Salmonella choleraesuis C500 strain was an attenuated vaccine strain used to prevent piglet paratyphoid,attenuated from virulent strain C78-1 by chemical method.Although the vaccine has good immunogenicity,it remains some residual virulence.SC-1 was a virulent Salmonella choleraesuis strain isolated from clinical piglet.In order to develop a safer vaccine strain,cAMP receptor protein(crp) deletion mutant of C500,C78-1 and SC-1 was constructed by conjugation with recombination suicide vector.The virulence to mice of 6 strains,including SC-1,crp-SC-1,C78-1,crp-C78-1,C500 and crp-C500,were characterized.The LD50 results showed that crp delection little effect the virulence of Salmonella choleraesuis and crp-C500 mutant was the lowest.In collusion,crp-C500 mutant can be used as an candidate strain for preparing Salmonellacholeraesuis attenuated vaccine.