A single dose of dendrimer B2T peptide vaccine partially protects pigs against foot-and-mouth disease virus infection

Foot-and-mouth disease virus (FMDV) causes a highly contagious disease of cloven-hoofed animals whose control relies on efficient vaccination. We have reported that dendrimer peptide B2T, with two copies of FMDV B-cell epitope VP1 (136-154) linked through maleimide units to T-cell epitope 3A (21-35)], elicits potent B- and T-cell specific responses and confers solid protection in pigs to type-O FMDV challenge after two doses of peptide. Herein we now show that B2T evokes specific protective immune responses after administration of a single dose of either 2 or 0.5 mg of peptide. High titers of ELISA and neutralizing antibodies against FMDV were detectable at day 15 post-immunization. Likewise, activated T cells and induced IFN-γ response to in vitro recall with FMDV peptides were also detected by the same day. Further, in 70% of B2T-vaccinated pigs, full protection-no clinical signs of disease-was observed upon virus challenge at day 25 post-immunization. These results strengthen the potential of B2T as a safe, cost-effective candidate vaccine conferring adequate protection against FMDV with a single dose. The finding is particularly relevant to emergency scenarios permitting only a single shot immunization.This work was supported by the Spanish Ministry of Science, Innovation and Universities (grant AGL2017-89097-C2 to FS and DA; AGL2016-76445-R to EB), Comunidad de Madrid co-financed with ECFEDER funds (S2013/ABI-2906-PLATESA and P2018/BAA-4370 to FS and EB) and Generalitat de Catalunya (2009SGR492 to DA). 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. R.C.-A. and M.F. were holders of a PhD fellowship from the Spanish Ministry of Science, Innovation and University (FPI programme). Article processing free of charge