Co-administration of porcine-specific CpG oligodeoxynucleotide enhances the immune responses to pseudorabies attenuated virus vaccine in newborn piglets in vivo

Oligonucleotides containing CpG motifs (CpG ODN) are strong adjuvants for humoral and cellular immune responses in mice, but data on immune responses in piglets are scarce. In this report, porcine-specific CpG ODN were used as immunoadjuvants to enhance the immune responses of the newborn piglets to Pseudorabies attenuated virus (PRV) vaccine. The titres of specific antibodies and serum IgG1/IgG2 ratio to PRV vaccine, the proliferation of peripheral blood mononuclear cells (PBMCs), IL-4 and interferon-γ(IFN-γ) in piglets serum were examined to identify the immune response of the newborn piglets. The results showed that piglets immunized with PRV vaccine and CpG ODN presented high titers of PRV-specific antibodies and IgG2 isotype, a Th1-dominated (IFN-γ) cytokine profile, together with inducing higher proliferation of PBMCs. All these data indicate that CpG ODN are potential effective adjuvants for the PRV vaccine in newborn piglets.