ANTIBODIES TO THE VITRONECTIN RECEPTOR (INTEGRIN ALPHA(V)BETA(3)) INHIBIT BINDING AND INFECTION OF FOOT-AND-MOUTH-DISEASE VIRUS TO CULTURED-CELLS

The amino acid sequence Arg-Gly-Asp (RGD) is highly conserved on the VP1 proteins of different serotypes and subtypes of foot-and-mouth disease virus (FMDV) and is essential for cell attachment. This sequence is also found in certain extracellular matrix proteins that bind to a family of cell surface receptors called integrins. Within the Picornaviridae family, human enterovirus coxsackievirus A9 also has an RGD motif on its VP1 capsid protein and has recently been shown to utilize the vitronectin receptor integrin alpha(v) beta(3) as a receptor on monkey kidney cells. Competition binding experiments between type A(12) FMDV and coxsackievirus A9 using BHK-21 and LLC-MK2 cells revealed shared receptor specificity between these two viruses. Polyclonal antiserum to the vitronectin receptor and a monoclonal antibody to the alpha(v) subunit inhibited both FMDV binding and plaque formation, while a monoclonal antibody to the beta(3) subunit inhibited virus binding. In contrast, antibodies to the fibronectin receptor (alpha(5) beta(1)) or to the integrin (alpha(v) beta(5)) had no effect on either binding or plaque formation. These data demonstrate that the alpha(v) beta(3) vitronectin receptor can function as a receptor for FMDV.