牛坏死杆菌是引起牛多种器官坏死性感染的主要病原菌，给养牛业带来严重危害。病原菌对宿主细胞的黏附是建立感染的第一步。目前，牛坏死杆菌黏附宿主细胞的相关蛋白尚不明确。在前期研究中，我们在牛坏死杆菌中鉴定了1个43Ku的外膜蛋白（43K-OMP），其具有黏附宿主细胞的潜在作用。为了明确43K-OMP在牛坏死杆菌黏附宿主细胞中的作用，本研究拟通过抗体/天然蛋白的竞争抑制实验，在牛坏死杆菌感染宿主不同靶器官的原代细胞上，明确牛坏死杆菌43K-OMP的黏附作用；通过免疫共沉淀、GST-pull down、靶蛋白非宿主表达细胞系和靶基因沉默与过表达等方法和技术，鉴定牛坏死杆菌43K-OMP黏附宿主不同靶细胞的受体蛋白；以鼠为模型，通过体内实验，评价43K-OMP作为疫苗抗原对牛坏死杆菌感染的抑制作用。本研究成果将为牛坏死杆菌的致病机理及抗菌药物设计提供新的理论基础。

Fusobacterium necrophorum (F. necrophorum) is a primary pathogen caused the necrotic infection of the various organs in cattle, and affects seriously the cows-rearing industry. The adhesion of bacteria to host cells is the first step in the establishment of infection. At present, adhesion-associated proteins of the F. necrophorum remained unknown. Outer membrane proteins (OMPs) have been reported as adhesion factors of host cells in gram-negative anaerobic bacilli, becoming a research focus. In our previous study, a 43 Ku of outer membrane protein (43K-OMP) was identified in the F. necrophorum strain H05. The 43K-OMP has a potential role in adhesion of F. necrophorum to host cells. To confirm the adhesion function of the 43K-OMP, the competition/inhibition experiments based on antibodies or natural 43K-OMP were carried out in primary cells from the targeted tissues for F. necrophorum; the receptor proteins that the 43K-OMP adheres host cells from bovine liver cells, hoof tissue cells, breast epithelial cells, and endometrial epithelial cells were identified by using co-immunoprecipitation (Co-IP), GST-pull down, over-expression/silencing of the targeted proteins, and expression of the targeted proteins in the non-host cell lines; and the preventive effect of the 43K-OMP recombinant protein as vaccine candidate on bovine F. necrophorum infection was evaluated through in vivo experiments in the moue model. These data will provide novel basis for understanding of pathogenic mechanism and antimicrobial drug design of bovine F. necrophorum.