外膜囊泡（OMV）是病原菌重要的毒力载体，可携带毒力因子与细胞互作导致宿主感染。禽致病性大肠杆菌（APEC）防治是世界性难题，前期研究表明：OMV与APEC致病性密切相关，其侵染上皮细胞是导致细菌感染的关键步骤，探明两者的互作关系有利于揭示APEC致病机理，但相关研究尚未见报道。为此，本项目选取APEC-OMV为研究对象，应用蛋白质组学及生物信息学技术结合致病性评价，筛选出APEC-OMV关键毒力因子；继而，应用iTRAQ技术锚定APEC-OMV对上皮细胞的胞内调控靶点，应用酵母双杂交和免疫共沉淀技术确定与其互作的胞内蛋白；最后，构建APEC-OMV体内外感染SPF雏鸡及上皮细胞模型，运用免疫荧光及活体成像技术观察其迁移轨迹及细胞定位、检测其致上皮细胞病理变化及胞内互作蛋白、细胞因子表达水平，初步揭示APEC-OMV的致病机制，这对于阐明APEC的致病机理并实现该病的防控具有重大科学意义。

Outer membrane vesicles (OMV) are important virulence carriers of pathogenic bacteria, which can carry virulence factors and interact with cells to cause host infection. Prevention and control of avian pathogenic Escherichia coli (APEC) is a worldwide problem. Previous studies have shown that OMV is closely related to the pathogenicity of APEC, and the infection of epithelial cells by OMV is the key step leading to bacterial infection. It is helpful to reveal the pathogenic mechanism of APEC to elucidate the interaction between OMV and APEC, but the related research has not yet been reported. In this project, APEC-OMV will be selected as the research object, and key virulence factors of APEC-OMV will be screened by proteomics, bioinformatics and pathogenicity evaluation technology. Then, iTRAQ technology will be used to anchor the intracellular regulatory targets of APEC-OMV in epithelial cell, yeast two-hybrid and co-immunoprecipitation technology will be used to determine the intracellular proteins interacting with APEC-OMV. Finally, the in vivo and in vitro model of APEC-OMV will be constructed. Using immunofluorescence and in vivo imaging techniques, the migration trajectory of OMV will be observed in SPF chickens and the cell localization of OMV will be observed in epithelial cells, the pathological changes of epithelial cells, the expression levels of intracellular interaction proteins and cytokines will be detected, and the pathogenic mechanism of APEC-OMV will be preliminarily revealed, which is of great scientific significance to elucidate the pathogenic mechanism of APEC and to achieve the prevention and control of APEC.