Adherence of Pasteurella multocida to fibronectin

For many pathogens, adherence and/or invasion involve association with host extracellular matrix molecules, such as fibronectin (Fn). Pasteurella multocida was found to bind significantly to Fn and collagen type IX but not to laminin and collagen types IV and X. The binding of P. multocida to Fn was dose-dependent and was inhibited by heparin (Hep). Removal of polysaccharide capsule enhanced the binding capacity of the bacterium to Fn and inhibition by Hep. Protease treatment of bacteria decreased binding, implicating surface protein(s) as adhesive components. Investigation of the binding domain(s) of P. multocida on the Fn molecule revealed preferential binding to the N-terminal Hep-binding domain of Fn but not to the carboxyl-terminal Hep-binding domain. Furthermore, Fn, and anti-Fn antibodies inhibited P. multocida adherence to Madin-Darby bovine kidney cells, suggesting the involvement of Fn in the bacterium adherence to host cells. Ligand blotting, batch affinity purification and MALDI-TOF mass spectrometry implicated several proteins as putative adhesins of P. multocida in the Fn-mediated adherence. Taken together, the data suggest that P. multocida-Fn interaction may play a role in the bacterium adherence to host cells, and this may be mediated by bacterial surface proteins with preferential affinity for the Hep-1 binding domain of Fn.