Prime-boost immunization using DNA vaccine and recombinant Orf virus protects pigs against Pseudorabies virus (Herpes suid 1).

The present study demonstrates the protective potential of a novel prime-boost vaccination strategy of pigs against lethal Pseudorabies virus (PRV; Herpes suid 1) infection. Animals were primed with Sindbis virus-derived plasmids that express viral glycoproteins gC and gD (gC- and gD-pSIN) and subsequently booster immunized with Orf virus (ORFV; Parapoxvirus) recombinants expressing gC and gD (D1701-VrVgC and -VrVgD). The prime-boost vaccination induced strong humoral and cellular-like PRV-specific immune responses. All prime-boost vaccinated pigs survived the lethal challenge infection without PRV-specific clinical symptoms and presented excellent body weight loss attenuation. Most notably, nasal shedding of challenge virus was reduced by more than about 3log(10), clearly reducing the risk of infection of non-immunized pigs.