Structural and molecular basis for foot-and-mouth disease virus neutralization by two potent protective antibodies

Foot-and-mouth disease (FMD) is an economically devastating and highly contagious viral disease of cloven-hoofed animals with a global distribution. The causative agent, FMD virus (FMDV) is a small non-enveloped RNA virus, belonging to the Aphthoviruses genus within Picornaviridae family (Tuthill et al., 2010). Control of FMD has been largely reliant on vaccinations with inactivated virus vaccines. However, significant antigenic diversity within FMDV serotypes and inability of the vaccines to induce immune protection for a long duration of time impinge on the efficacy of available vaccines. The roles of neutralizing antibodies (NAbs) as the principal protective components of the immune responses to FMDV vaccination or infection have been well established (Pay and Hingley, 1987; Juleff et al., 2009). Passive immunization of NAbs has also been demonstrated to be effective in curing FMD and many viral diseases (Harmsen et al., 2007; Qiu et al., 2018). A deep understanding of the molecular basis for viral neutralization by antibodies and the identification of key viral epitopes would aid in the development of potent rationally designed broad-spectrum vaccine.