Improved neutralising antibody response against foot-and-mouth-disease virus in mice inoculated with a multi-epitope peptide vaccine using polyinosinic and poly-cytidylic acid as an adjuvant

A peptide-based vaccine for foot-and-mouth disease (FMD) was designed. The peptide immunogen had a G-H loop domain optimised for immunogenicity and broad-spectrum antigenicity to different lineages of serotype-O FMD viruses (FMDVs). Polyinosinic and poly-cytidylic acid [poly (I:C)] was used as the adjuvant to overcome the low humoral antibody levels often observed in association with peptide-based vaccines. The multi-epitope peptide alone induced the secretion of a certain level of neutralising antibodies in mice. In contrast, co-administration of the multi-epitope peptide with poly (I:C) induced the secretion of a significantly higher level of neutralising antibodies (P < 0.005). Indeed, the resultant level was slightly higher even than that induced by the inactivated vaccine (P > 0.05). These initial results indicate that poly (I:C) is highly effective as an adjuvant for use with the FMDV multi-epitope peptide vaccine. This combination could yield a promising vaccine for the prevention and control of FMD. Further study is needed to evaluate the efficiency of this combination on animals susceptible naturally to FMDV.