Sequence analysis of monoclonal antibody resistant mutants of type O foot and mouth disease virus: evidence for the involvement of the three surface exposed capsid proteins in four antigenic sites.

Sequence analysis of monoclonal antibody resistant mutants of type O foot and mouth disease virus has been performed. Distinct clusters of amino acid substitutions conferring resistance to neutralization at each of the four previously defined antigenic sites (McCahon et al., 1989, J. Gen. Virol. 70, 639-645) have been identified. One site corresponds to the well-known 140-160 region of VP1, a second site is also on VP1, one site is on VP2, and the fourth site is on VP3. All of the amino acid substitutions identified are located on the surface of the virus. Despite the differences in three-dimensional structure between FMDV and other picornaviruses the neutralizing antigenic sites occur in analogous positions on the capsid surface.