Immune Potential of a Novel Multiple-epitope Vaccine to FMDV Type Asia 1 in Guinea Pigs and Sheep

To develop a safe and efficient recombinant subunit vaccine to foot-and-mouth disease virus (FMDV) type Asia 1 in sheep, a tandem repeated multiple-epitope gene consisting of residues 137-160 and 197-211 of the VP1 gene of FMDV was designed and artificially synthesized. The biologically functional molecule, the ovine IgG heavy constant region (oIgG) as a protein carrier was introduced for design of the multiple-epitope recombinant vaccine and recombinant expression plasmids pET-30a-RE and pET-30a-RE-oIgG were successfully constructed. The recombinant proteins, RE and RE-oIgG, were expressed as a formation of inclusion bodies in E. coli. The immune potential of this vaccine regime in guinea pigs and sheep was evaluated. The results showed that IgG could significantly enhance the immune potential of antigenic epitopes. The recombinant protein RE-oIgG could not only elicit the high levels of neutralizing antibodies and lymphocytes proliferation responses in the vaccinated guinea pigs, but confer complete protection in guinea pigs against virus challenge. Although the recombinant protein RE could not confer protection in the vaccinated animals, it could delay the appearance of the clinical signs and reduce the severity of disease. Inspiringly, the titers of anti-FMDV neutralizing antibodies elicited in sheep vaccinated with RE-oIgG was significantly higher than that for the RE vaccination. Therefore, we speculated that this vaccine formulation may be a promising strategy for designing a novel vaccine against FMDV in the future.

Preparation and Characterization of Monoclonal Antibodies against VP1 Protein of Foot-and-mouth Disease Virus O/China99

Monoclonal antibodies (McAbs) 1A9 and 9F12 against Foot-and-mouth disease virus (FMDV) serotype O were produced by fusing SP2/0 myeloma cells with splenocyte from the mouse immunized with O/China99. Both McAbs reacted with O/China99 but not with Asia 1, as determined by immunohistochemistry assay. The microneutralization titer of the McAbs 1A9 and 9F12 were 640 and 1 280, respectively. Both McAbs contain kappa light chains, but the McAbs 1A9 and 9F12 were IgG1 and IgM, respectively. In order to define the McAbs binding epitopes, the reactivity of these McAbs against VP1, P20 and P14 were examined using indirect ELISA, the result showed that both McAbs reacted with VP1 and P20. McAbs may be used for further studies of vaccine, diagnostic methods, prophylaxis, etiological and immunological researches on FMDV.