Sigma B基因缺失对单核细胞增生性李斯特菌毒力的影响

Effect of SigmaB Gene Deletion on Virulence of Listeria monocytogenes

为了解缺失SigmaB基因对单核细胞增生性李斯特菌(LM)的毒力影响。通过体外生长试验、巨噬细胞RAW264.7的粘附与侵袭试验、小鼠肝脾载菌量试验、毒力基因转录水平试验、小鼠LD50试验来研究缺失株(LM-XS5-△SigmaB)的毒力变化。结果显示,与野毒株相比,缺失株体外生长能力减弱、侵袭率和粘附率降低,小鼠肝脾载菌量显著减少,毒力基因(inlA、inlB、hly、prfA、actA)的转录水平降低,而小鼠LD50升高。可见,SgmaB基因对LM的毒力具有重要的调控作用,为LM基因缺失疫苗和活疫苗载体的研发可资借鉴。

In order to study the effect of SigmaBgene deletion on virulence of Listeria monocytogenes（LM）,the virulence change of mutant strain（LM-XS5-△SigmaB）was analyzed through the in vitro growth test,the rate of invasion and adhesion to macrophages RAW264.7,the bacterial number of liver and spleen in mice,the transcription level of virulence genes and mice LD50measurement.The results showed that the in vitro growth ability of mutant strain decreased,the invasion and adhesion capacity reduced,the bacterial loading of liver and spleen decreased significantly,the transcription levels of five virulence genes（inlA,inlB,hly,prfA,actA）also reduced,the LD50increased compared with wild strain.This study showed SigmaBgene has an important regulatory effect on virulence of LM and provided a reference for the development of LM gene deletion vaccines and live vaccine vector.