单核细胞增生性李斯特菌(Listeria monocytogenes,LM)是一种毒力较强、人畜共患的食源性致病菌,其具有穿透宿主屏障、胞内寄生的特点,因而致死率较高,被其污染的食品容易引发严重的食品安全问题.本研究使用前期构建的LM重要的毒力因子内化素A(intemalin A,InlA)和InlB基因缺失菌株,以人结肠癌腺细胞Caco-2和入肝癌上皮细胞HepG2为研究对象,探究InlA和InlB缺失对LM侵袭宿主细胞和诱导细胞凋亡的影响.实验结果表明,InlA和InlB的缺失使LM侵袭宿主细胞的能力明显降低(P＜0.05),与野生株相比侵袭量下降超过50％,同时也降低了其诱导宿主细胞凋亡的能力(P＜0.05),与野生株相比凋亡细胞的比例下降幅度达到30％～50％.本实验确定了InlA和InlB在LM侵袭宿主细胞和诱导细胞凋亡的过程中具有重要的作用,有助于对LM的致病机理以及引起宿主相关免疫反应、诱导细胞凋亡相关分子机制的深入研究.%Listeria monocytogenes (LM) is a zoonotic food-borne pathogen with strong virulence.It has a high lethality due to the host barrier penetrability and intracellular parasitism.Hence,consumption of foods contaminated with LM causes food safety problems.In this study,LM strains with the deletion of the gene encoding the important virulence factors such as intemalin A (InlA) and intemalin B (InlB) and human colon Caco-2 and liver HepG2 cells were used to investigate the effect of inlA and inlB gene deletion on the ability of LM to invade host cells and induce cell apoptosis.The results showed that inlA and inlB deletion significantly reduced the ability of LM to invade host cells and induce cell apoptosis (P ＜ 0.05)and resulted in a decrease of over 50％ in invasion rate and a decrease of 30％-50％ in the proportion of apoptotic cells compared with the wild-type strain.Therefore,inlA and inlB were confirmed to play an important role in host invasion and cell apoptosis induction by LM,which is helpful to intensively study the nosogenesis of LM and the molecular mechanisms by which LM causes host immunoreaction and induces cell apoptosis.
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