Abstract
Porcine reproductive and respiratory syndrome (PRRS) is a disease causes by porcine reproductive and respiratory syndrome virus (PRRSV). PRRS clinical symptoms are inappetence, fever, diarrhea and make farrowing sows birth mummified piglets. Developing PRRS vaccine is the best strategy to reduce economic loss. Existing commercial vaccines have problem is using on piglet have window period, so we try to develop a vaccine which have can vaccination on pre-weaning piglet in the long term. First we try to combine baculovirus-based vector with Cre/LoxP recombination system. Recombination system make our target gene form episome that stable episome can remain in the cell. We confirm that Cre/LoxP system working on the pig kidney cell (PK(15)), but N protein don’t have high exression level. Second we use baculovirus expression system to produce PRRS virus GP5 and M protein in High FiveTM cell as subunit vaccine. We designed gp64 signal peptide on GP5 replace GP5 ownself signal peptide to optimize secretory signal peptides. The result show that no significant difference between Bac-GP5 and Bac64-GP5. We found that only Bac-GP5, Bac64-GP5, Bac64-GP5dN, Bac64-M could secrete GP5 and M in medium, the others couldn’t. Co-infection GP5 and M protein in High FiveTM could form heterodimer that can induce better immunity than monomer. These result show our antigen is a potent vaccine candidate against PRRS virus.