Immunogenicity of plasmids encoding P12A and 3C of FMDV and swine IL-18

In this paper, two recombinant plasmids (pVIR-P12AIL18-3C and pVIR-P12A-3C) containing foot and mouth disease virus (FMDV) capsid polypeptide, 3C coding regions of O/NY00 and using/or not swine IL18 as a genetic adjuvant were constructed, and evaluated for their ability to induce humoral and cellular responses in mice and swine. In addition, the ability to protect swine against homologous virus challenge was examined. Mice and swine were given booster vaccination twice and once, respectively, and swine were challenged 10 days after the booster vaccination. Control groups were inoculated with pVAX1 or phosphate-buffered saline (PBS). All animals vaccinated with pVIR-P12AIL18-3C and pVIR-P12A-3C developed specific anti-FMDV ELISA antibody and neutralizing antibody and T lymphocyte proliferation and CTL cytotoxic activity was observed. In addition, we found that pVIR-P12AIL18-3C possessed stronger immunogenicity than pVIR-P12A-3C. The pVIR-P12AIL18-3C and pVIR-P12A-3C provided full protection in 3/4 and 2/4 swine from challenge with FMDV O/NY00, respectively. The results demonstrate the potential viability of a DNA vaccine in the control and prevention of FMDV infections.