布鲁氏菌VirB8变异株的构建及其感染力和毒力的测定

Construction of VirB8 Deletion Mutants of Brucella and Detection of Its Infection and Virulence

作者拟对缺失致病力因子——四型分泌系统中的VirB8基因后布鲁氏菌感染力和毒力的变化进行测定与分析。首先,构建了布鲁氏菌VirB8基因缺失株(△B8B.suis),用缺失株感染巨噬细胞和BALB/c小鼠,再用B.suis强毒攻击BALB/c小鼠并检测脾脏含菌数,观察其在动物体内定居能力、毒力及抗感染保护力。鉴定△B8B.suis为VirB8基因完全缺失株,△B8B.suis感染巨噬细胞6、24和48 h,其CFU分别为49、165和355;△B8B.suis感染BALB/c小鼠的每克脾含菌数为3.6×107(1×108CFU腹腔接种)和5×106(1×109CFU蹊部接种);BALB/c小鼠攻毒试验显示△B8B.suis免疫组每克脾平均含菌数为7.61×102,非免疫对照组为2.98×105。结果表明布鲁氏菌缺失VirB8基因后,其毒力较亲本株弱,但能在小鼠脾脏定居,为弱毒株;△B8B.suis呈现出作为疫苗的生物学特性,但毒株能否作为疫苗株使用,还需进一步验证。

VirB8 deletion mutant of Brucella was constructed and named △B8B. suis. Then the virulence and potential protection efficacy of the AB8B. suis were evaluated by inoculating macro- phages and BALB/c mouse. After culturing in macrophages, bacteria were recovered 6, 24, 48 h, and the mean CFU were 49, 165 and 355 respectively. Splenic CFU of BALB/c mouse were 3.6×10^7 （Mice was inoculated with 1×10^8CFU in abdominal cavity） and 5.6 ×10^5 （Mice was in- oculated with 1 ×10^9CFU in inguinal region）. After challenging, the splenic CFU of △BSB. suis immunization group was 7.61×10^7 ,while that of control group （No inoculation） was 2.98×10^8 The mutation of △BSB. suis was attenuated in macrophages and mouse model. It was able to col- onize in spleen of BALB/c mouse and had some protective efficacy against Brucella suis. This ap- proach provides a useful candidate vaccine for protecting animals from Brucella infection.