Abstract: Herein, we attempted to clarify the adhesion characterization of 43K OMP of bovine Fusobacterium necrophorum.In this study, 43K OMP gene of F. necrophorum was cloned into pET-32a vector and the proteins were subsequently expressed on the surface of E. coli BL21 DE3 cells. The attachment assay, antibody inhibition attachment assay, native protein inhibition assay and proteinase treatment assay were used to determine the adhesion characterization of 43K OMP in bovine F. necrophorum. Meanwhile, the recombinant protein and naive 43K OMP were co-incubated with bovine endometrial epithelial cells or bovine mammary epithelial cells(MAC-T), and then evaluated the adhesion effect of 43K OMP of F. necrophorum to bovine epithelial cells. The 43K OMP gene was cloned into pET-32a vector and the recombinant 43K OMP in the form of an inclusion body was present in the bacterial precipitation. When E. coli carrying the recombinant plasmid (H2019) was induced by IPTG, there was significant enhancement in the binding to host cells compared to the E. coli carrying control vector only(P<0.05). When fixed cells were incubated with purified native 43K OMP, H2019 showed lower levels of binding(P<0.05). Pre-incubation of induced H2019 with polyclonal antibodies or monclonal antibodies against the 43K OMP reduced the binding amount to host cells(P<0.05). The adhesion of F. necrophorum was significantly decreased after proteinase K treatment(P<0.05), and dose-dependent relationship was shown between the decrease degree of adhesionto host cells and the concentrations of proteinase K. At the same time, the native 43K OMP and recombinant 43K OMP could bind to bovine endometrial epithelial cells or MAC-T cells. The 43K OMP of bovine F. necrophorum possessed the ability of adhesion to bovine host cells, and the 43K OMP acted as an adhesion protein to improve the binding ability of bovine F. necrophorum to host cells.

Key words: bovine Fusobacterium necrophorum, 43K OMP, bacterial adhesion, epithelial cells