Baculovirus surface display of Erns envelope glycoprotein of classical swine fever virus

Classical swine fever virus (CSFV) causes significant losses in the pig industry in many countries. Erns is an envelope glycoprotein of CSFV which is known to induce virus-neutralizing antibodies and protective immunity in the natural host. In this study, one recombinant baculoviruses BacSC-Erns expressing histidine-tagged Erns with the transmembrane domain (TM) and cytoplasmic domain (CTD) derived from baculovirus envelope protein gp64 was constructed and its immunizing efficacy was evaluated in a mouse model. After infection, Erns was expressed and anchored on the plasma membrane of Sf-9 cells, as demonstrated by Western-blot and confocal microscopy. Immunogold electron microscopy demonstrated that the Erns glycoprotein was successfully displayed on the baculoviral envelope. Vaccine tests in animals showed that BacSC-Erns elicited significantly higher Erns antibody titers in the immunized mouse models than the control group. This demonstrates that the BacSC-Erns vaccine can be used potentially against CSFV infections. This is the first report demonstrating the potential of Erns-pseudotyped baculovirus as a CSFV vaccine.