Mycoplasma bovis is a highly infectious pathogenic microorganism that causes various clinical signs in cattle, including pneumonia, arthritis, and mastitis, often resulting in significant economic losses. The adhesion of M. bovis to host cells is a pivotal step in the infection process, which is a complex process involving multiple pathogenic and host proteins. Molecules involved in M. bovis adhesion and colonization are widely recognized as important virulence factors and often implicated in the infection and pathogenesis. In this study, the Mbov_0510 gene of M. bovis was cloned, and the protein encoded by this gene was expressed and purified. The rabbit polyclonal antibody against this protein was also produced. This protein was shown to be a surface protein and to react with the M. bovis-positive serum. The ability of this protein to adhere to host cells was verified using embryonic bovine lung (EBL) and Madin-Darby bovine kidney (MDBK) cells. Furthermore, the adhesion function of this protein was found to be achieved through interaction with heparin on the host cell surface, and the key region of the protein involved in heparin binding was identified. The conservation of the protein encoded by the Mbov_0510 gene was also analyzed. The results of this study suggest that the protein encoded by the Mbov_0510 gene is a heparin-binding surface membrane protein of M. bovis associated with infection.IMPORTANCEMycoplasmas lack a cell wall, and the membrane proteins interacting with host cells play essential roles in their infection and proliferation processes. In this study, we identified a membrane protein encoded by Mycoplasma bovis that interacts with heparin on the surface of host cells. Heparin is widely distributed in various cells and tissues of the host and serves as a receptor for the infection and invasion of many pathogenic microorganisms. The ability of M. bovis to invade multiple tissues may be related to its heparin-binding capacity. The heparin-binding protein identified in this study is valuable for further research on the infection and invasion mechanisms of M. bovis.

Keywords: M. bovis; adhesion; heparin; immunogenicity.