Construction and immunogenicity of pseudotype baculovirus expressing GP5 and M protein of porcine reproductive and respiratory syndrome virus.

Baculovirus, which is extensively utilized as an excellent tool for production of recombinant protein in insect cells, has recently emerged as a novel and attractive gene delivery vehicle for mammalian cells. In the present study, a pseudotype baculovirus (with the glycoprotein of vesicular stomatitis virus (VSV-G) on the envelope) was used as vector to construct recombinant baculovirus coexpressing GP5 and M protein of porcine reproductive and respiratory syndrome virus (PRRSV), under the transcriptional control of two independent cytomegalovirus immediate early (CMV-IE) enhancer/promoters. The resultant recombinant baculovirus (BV-G-5m6) efficiently expressed PRRSV GP5 and M protein in mammalian cells. Intramuscular injection of BV-G-5m6 with various doses (1 x 10(8), 1 x 10(9), and 1 x 10(10)PFU/mouse) induced the production of PRRSV-specific neutralizing antibodies and gamma interferon (IFN-gamma) under dose-dependent pattern. Furthermore, BV-G-5m6 performed better immunogenicity, even at low dose (10(8)PFU), than DNA construct (pCI-5m6) encoding the same antigens, as demonstrated by significantly enhanced neutralizing antibodies and IFN-gamma production. These results indicate that pseudotype baculovirus-mediated gene delivery can be utilized as an alternative strategy to develop new generation of vaccine against PRRSV infection.