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.