Peptide-based vaccines: foot-and-mouth disease virus, a paradigm in animal health

Vaccines are considered one of the greatest global health achievements, improving the welfare of society by saving lives and substantially reducing the burden of infectious diseases. However, few vaccines are fully effective, for reasons ranging from intrinsic limitations to more contingent shortcomings related, e.g., to cold chain transport, handling and storage. In this context, subunit vaccines where the essential antigenic traits (but not the entire pathogen) are presented in rationally designed fashion have emerged as an attractive alternative to conventional ones. In particular, this includes the option of fully synthetic peptide vaccines able to mimic well-defined B- and T-cell epitopes from the infectious agent and to induce protection against it. Although, in general, linear peptides have been associated to low immunogenicity and partial protection, there are several strategies to address such issues. In this review, we report the progress towards the development of peptide-based vaccines against foot-and-mouth disease (FMD) a highly transmissible, economically devastating animal disease. Starting from preliminary experiments using single linear B-cell epitopes, recent research has led to more complex and successful second-generation vaccines featuring peptide dendrimers containing multiple copies of B- and T-cell epitopes against FMD virus or classical swine fever virus (CSFV). The usefulness of this strategy to prevent other animal and human diseases is discussed.This research was funded by the European Commission (project H2020-FETOPEN-2018-2019-2020-01 n° 828774), by the Spanish Ministry of Science, Innovation and Universities, grants AGL2014-48923-C2 and AGL2017-84097-C2-2-R (to D.A. and F.S.), and AGL2016-349 76445-R (to E.B.), as well as by Comunidad de Madrid co-financed ECFEDER funds (S2013/ABI-350 2906-PLATESA and P2018/BAA-4370 to F.S. and E.B.), and by Generalitat de Catalunya (2009SGR492 to D.A.). Work at Centro de Biología Molecular “Severo Ochoa” and at UPF was supported by Fundación Ramón Areces and by the Maria de Maeztu Program of the Spanish Ministry of Science, Innovation and Universities, respectively. M.F. and R.C.-A. were holders of a PhD fellowship from the Spanish Ministry of Science, Innovation and Universities