猪链球菌2型溶血素基因缺失株构建及其生物学特性分析

Construction and Characterization of Streptococcus suis type 2 Mutant Strain with Suilysin Gene Deletion

猪链球菌溶血素(SLY)是较早确定的猪链球菌毒力因子之一,具有细胞毒性,在猪链球菌致病过程中发挥重要作用。利用同源重组技术成功构建了猪链球菌2型(SS2)sly基因缺失的突变株SS2-Δsly,缺失株的体外溶血活性消失,对小鼠脑血管内皮细胞的细胞毒性显著低于亲本菌株(P<0.01),但不影响猪链球菌2型在巨噬细胞中的存活。该菌株可以用于研究SS2溶血素在感染细胞中的作用机制。

Suilysin（SLY）,one of the most important virulence factors of Streptococcus suis type 2（SS2）,plays an important role in the pathogenesis by its cytotoxic activity.We constructed a mutant SS2-Δsly with deletion of the sly gene from a clinical SS2 strain 1 105 by homologous recombination.Deletion of the sly gene abolished the hemolytic activity of SS2 and reduced cytotoxicity to Bend3 cell brain epithelial cells by more than 60% as compared with its parent strain.There was no significant difference between the mutant and parent strains in survival within macrophage cell lines Raw 246.7.The SS2-Δsly mutant strain could be used to explore the mechanisms of SLY in infected cells.