Mapping novel antigenic determinants on foot-and-mouth disease virus serotype Asia 1 using neutralising monoclonal antibody resistant mutants

Foot-and-mouth disease (FMD) is a severe and, highly contagious viral disease caused by FMD virus (FMDV) that primarily targets ungulates. Identifying neutralising antigenic sites on the virus is crucial for understanding the virus's antigenic characteristics. Numerous studies have pinpointed the critical residues of the neutralising antigenic sites in FMDV serotypes O, A, and C. However, information on serotype Asia 1 is very limited. This study reports the generation and characterization of forty-one monoclonal antibodies (mAbs) against FMDV serotype Asia 1 (current Indian vaccine strain). Of these, a panel of 23 neutralising mAbs was utilized to generate mAb resistant (MAR) mutants for mapping the virus's antigenic sites. New critical residues defining sites 1, 2, and 4 in FMDV serotype Asia 1 were identified. These findings significantly enhance our understanding of the antigenic nature of FMDV serotype Asia 1, and provide insights to designing broadly acting vaccines against FMD.