A prime-boost vaccination strategy using naked DNA followed by recombinantporcine adenovirus protects pigs from classical swine fever

Weaned pigs (6-week-old) and 7-day-old pre-weaned piglets were vaccinated w ith naked plasmid DNA expressing the gp55/E2 gene from classical swine feve r virus (CSFV). Both groups of pigs were then given a booster dose of recom binant porcine adenovirus expressing the gp55 gene (rPAV-gp55). Following c hallenge with CSFV: 100% of weaned pigs and 75% pre-weaned piglets were pro tected from disease. Weaned pigs given a single dose of rPAV-gp55 were also protected, but showed a slight increase in temperature immediately post-ch allenge. However. weaned animals given a DNA prime before rPAV-gp55 showed no fluctuation in body temperature following challenge and no pathology in spleen or lymph nodes upon post-mortem, In addition, no CSFV could be re-is olated from the rPAV vaccinated group and from only one pig in the prime-bo ost group following challenge, suggesting that both vaccination regimes hav e the potential to reduce or prevent virus shedding following experimental. challenge. (C) 2001 Elsevier Science B.V. All rights reserved.