Enhanced protective immune response to PCV2 subunit vaccine by co-administration of recombinant porcine IFN-γ in mice

► Three recombinant proteins of PCV2-Cap, PoIFN-γ and Cap-PoIFN-γ were expressed. ► Three PCV2 subunit vaccines were generated based on the three recombinant proteins. ► The immunogenicity of the three PCV2 subunit vaccines was confirmed in mice. ► The PCV2-Cap + PoIFN-γ vaccine induced greater protective immunity than other vaccines. ► PoIFN-γ essentially enhanced the protective immune response to the PCV2-Cap vaccine.