致病性大肠杆菌致结肠癌细胞微绒毛损伤的毒力分子研究  

Investigation the effectors involved in the effacement of microvilli of colon cancer TC-7 cells infection with enteropathogenic escherichia coli

作　　者：周诗璞[1] 林华 杨健[3] ZHOU Shi-pu;LIN Hua;YANG Jian(Department of Infectious Disease of People＇ s Hospital of Tongjiang,Bazhong 636700;Quarantine Technical Center of Entry-exit In-spection of Sichuan,Chengdu 610000;College of Basic Medicine of North Sichuan Medical College,Nanchong 637000,Sichuan,Chi-na)

机构地区：[1]通江县人民医院感染科,四川巴中636700 [2]四川省出入境检验检疫技术中心,四川成都610041 [3]川北医学院基础医学院,四川南充637000

出　　处：《川北医学院学报》2018年第4期520-523,共4页Journal of North Sichuan Medical College

基　　金：四川省教育厅重点项目(15ZA0205)

摘　　要：目的:PEC感染结肠癌TC-7细胞致微绒毛损伤的毒力分子。方法:分别用EPEC野毒株、III型分泌系统删除株(Δcfm-14)、束状菌毛删除株(Δbfp A)、外膜蛋白删除株(Δeae)、效应分子Map删除株(Δmap)、效应分子Map和Esp F联合删除株(Δmap esp F)、外膜蛋白受体删除株(Δtir)及相应质粒互补株感染TC-7细胞,通过扫描电镜(SEM)检测细菌黏附及TC-7细胞微绒毛脱落损伤情况。结果:野生型EPEC感染时,大量细菌先局限性黏附,接着紧密黏附在TC-7细胞表面,细胞微绒毛大量脱落;Δbfp A感染时,极少细菌黏附细胞,微绒毛完好,但补充表达Bfp A后可以恢复到野生型表型;而Δcfm-14感染时,大量细菌局限性黏附,但微绒毛损伤轻微;Δeae或Δtir删除株感染TC-7细胞后,可见细菌呈局限性黏附,但细胞微绒毛大量脱落,相应质粒表达互补后可以恢复到野生型表型;而Δesp F或Δmap esp F感染TC-7细胞后,有大量细菌紧密黏附,细菌下陷入微绒毛丛,但微绒毛损伤轻微,质粒表达互补可恢复删除株表型。结论:多个效应分子参与EPEC黏附,但Esp F是造成微绒毛脱落损伤的重要分子。Objective： To investigate the virulence effectors of enteropathogenic escherichia coli（ EPEC） in the infection to TC-7 cells. Methods： Scanning Electron Microscopy（ SEM） was used to detect the effectors contributing to the attaching and effacing lesion of TC-7 cells infection with EPEC wide type,type III secretion system（ T3 SS） defective strain（ Δcfm-14）,bundle-forming pili defective mutant（ Δbfp A）,outer membrane protein intimin defective mutant（ Δeae）,effective effectors mitochondria associated protein（ Map） defective mutant（ ΔMap）,effective effectors Map and Esp F combination defective mutant（ Δmap esp F）,Intimin translocated receptor（ Tir） defective mutant（ ΔTir） and other effectors deleted mutants complement with corresponding plasmid expressing effectors. Results： Bacteria firstly localized adherence and then attached intimately to TC-7 cells,and microvilli were effaced generally when infection with EPEC wide type,yet when infection with Δcfm-14,bacteria localized adherence to host cells,but effacement was slight. Only a few bacteria attached to TC-7 cells and microvilli were intact when infection by Δbfp A mutant. The bacterial localized adherence to host cells but the effacement of microvilli was more severe than wide type when infection with Δeae or Δtir mutant and the phenotype were complemented by the protein expressed by the corresponding plasmids expressing Intimin or Tir. The bacterial adhered to host cells intimately and some bacteria sink into microvilli,but microvilli were intact when infection with Δesp F mutant or with Δmap esp F and the Esp F protein returned the phenotype of Δesp F or Δmap esp F to wild type Conclusion： Several effectors involved the adherence of EPEC to TC-7 cells,but Esp F is the crucial molecule of EPEC to efface the microvilli of TC-7 cells.

关 键 词：致病性大肠杆菌 Ⅲ型分泌系统 微绒毛 

分 类 号：R516.1[医药卫生—内科学]