Induction of protective immunity in swine by recombinant bamboo mosaic virus expressing foot-and-mouth disease virus epitopes

We engineered the BaMV as a vaccine vector expressing the antigenic epitope(s) of the capsid protein VP1 of foot-and-mouth disease virus (FMDV). The recombinant BaMV plasmid (pBVP1) was constructed by replacing DNA encoding the 35 N-terminal amino acid residues of the BaMV coat protein with that encoding 37 amino acid residues (T128-N164) of FMDV VP1.The pBVP1 was able to infect host plants and to generate a chimeric virion BVP1 expressing VP1 epitopes in its coat protein. Inoculation of swine with BVP1 virions resulted in the production of anti-FMDV neutralizing antibodies. Real-time PCR analysis of peripheral blood mononuclear cells from the BVP1-immunized swine revealed that they produced VP1-specific IFN-γ. Furthermore, all BVP1-immunized swine were protected against FMDV challenge.Chimeric BaMV virions that express partial sequence of FMDV VP1 can effectively induce not only humoral and cell-mediated immune responses but also full protection against FMDV in target animals. This BaMV-based vector technology may be applied to other vaccines that require correct expression of antigens on chimeric viral particles.Foot-and-mouth disease virus (FMDV) is the etiological agent of foot-and-mouth disease (FMD) that infects cloven-hoofed animals such as pigs, sheep and cattle and causes serious damage in the livestock industry [1]. Although conventional vaccines based on the chemically inactivated virus are effective against FMDV [2], outbreaks of FMD sometimes result from virus escaping from vaccine production units or from the use of improperly inactivated virus [2-4]. Alternative approaches to produce an effective and safe FMD vaccine are needed to replace inactivated virus-based vaccines.FMDV particles are composed of 60 copies of each of four capsid proteins termed VP1, VP2, VP3 and VP4, which are cleavage products of the capsid precursor polypeptide P1[5,6]. VP1, VP2 and VP3 form the outer capsid shell, whereas VP4 lines the interior surface [7]. Among these capsid