Abstract

Zhisheng Wang, Xingang Xu, Hungjen Liu , Zhaocai Li , Li Ding , Gaoshui Yu , Dan Xu and Dewen Tong

 In the present study, one recombinant baculovirus BacSC-GP5, expressing His6-tagged GP5 with the transmembrane domain (TM) and cytoplasmic domain (CTD) derived from baculovirus envelope protein gp64, was constructed and its immunogenicity and protective efficiency was evaluated in piglets. The results obtained show that, His6-tagged recombinant GP5 was expressed and anchored on the plasma membrane of Sf-9 cells, as revealed by Western blot and confocal microscopy. Immunogold electron microscopy demonstrated that, the GP5 glycoprotein was displayed successfully on the viral surface. Piglets immunized with BacSC-GP5 induced successfully GP5-specific enzyme-linked immunosorbent assay (ELISA) antibody, neutralizing antibody and lymphocyte proliferation response at 6 weeks after primary immunization. An in vivo challenge result indicated that piglets immunized with BacSC-GP5 did not show any obvious clinical signs and histological changes, and the quantitative real-time polymerase chain reaction (RT-PCR) also indicated that the porcine reproductive and respiratory syndrome virus (PRRSV) viral load from the serum in BacSC-GP5 group was significantly reduced at 14 and 21 days post-challenge compared to that in the negative control group. These results indicate that baculovirusmediated gene delivery can be utilized as an alternative strategy to develop a new generation of vaccine against PRRSV infection.