Ⅳ型菌毛HCP是肠出血性大肠杆菌O157:H7的重要毒力因子，是其定植和致病的关键因子，但其致病机制尚不明确。本项目用新生仔猪肠上皮细胞提取RNA，构建cDNA文库，酵母双杂交和细菌双杂交两种方法筛选与HCP互作的宿主蛋白因子，以期筛选到HCP的受体或直接作用的膜蛋白等。然后用GST pull down和免疫共沉淀技术验证筛选的阳性克隆。再针对阳性克隆的受体功能进行鉴定。选用亲本株EHEC O157:H7、缺失株EHEC O157:H7（△hcpA）和HB101（pJX22）对允许细胞HT-29和IPEC-2以及转染有阳性克隆基因的CHO细胞进行粘附和粘附抑制试验。综合分析，深入阐释EHEC O157:H7 HCP致病的机制，为人类O157:H7的防控奠定基础。

EHEnterohemorrhagic Escherichia coli (EHEC) O157:H7 produces long bundles of type Ⅳ pili (TFP) called hemorrhagic coli pili (HCP). HCP is an important and key virulence of EHEC O157:H7,but its pathogenic mechanism is unknown. We construct cDNA library by extracting RNA from intestinal epithelial cells of gnotobiotic newborn piglets, and screen host proteins interacted with HCP by yeast two-hybrid and bacterial two-hybrid to identify HCP receptors and receptor-like host proteins. The interactions between HCP and host proteins are confirmed by the GST pull-down and the co-immunoprecipitation technology. Receptor functions of host proteins are further identified. Parent EHEC O157: H7,EHEC O157: H7 (△ hcpA) and HB101(pJX22)are chosen to design adherence and adherence inhibition experiments by adhering to HT-29 cells, IPEC-2 cells and CHO cells transfected with the candidate host gene. In sum, we aim at deeply explain HCP pathogenic mechanisms of EHEC O157: H7 and lay the substantial foundation for the prevention and control of human O157:H7.