The outer membrane protein, OMP71, of Riemerella anatipestifer, mediates adhesion and virulence by binding to CD46 in ducks.

The Riemerella anatipestifer bacterium is known to cause infectious serositis in ducklings. Moreover, its adherence to the host's respiratory mucosa is a critical step in pathogenesis. Membrane cofactor protein (MCP; CD46) is a complement regulatory factor on the surface of eukaryotic cell membranes.