Generation of a subtype-specific neutralization epitope in foot-and-mouth disease virus of a different subtype.

An epitope involved in neutralization of foot-and-mouth disease virus (FMDV) of subtype C3 was generated by a single amino acid replacement in VP1 of FMDV of subtype C1. The replacement [Ser (139)----Ile, in the immunodominant site A] was consistently found in those FMDV C1 Santa Pau-Sp/70 mutants resistant to neutralization by monoclonal antibody (MAb) SD6 (specific for most C1 viruses) that acquired the capacity to be neutralized by MAb 7AB5 (specific for C3 viruses).