Immunogenicity and safety of virus-like particle of the porcine encephalomyocarditis virus in pig

Background: In this study, porcine encephalomyocarditis virus (EMCV) virus-like particles (VLPs) were generated using a baculovirus expression system and were tested for immunogenicity and protective efficacy in vivo. Results: VLPs were successfully generated from Sf9 cells infected with recombinant baculovirus and were confirmed to be approximately 30-40 nm by transmission electron microscopy (TEM). Immunization of mice with 0.5 mu g crude protein containing the VLPs resulted in significant protection from EMCV infection (90%). In swine, increased neutralizing antibody titers were observed following twice immunization with 2.0 mu g crude protein containing VLPs. In addition, high levels of neutralizing antibodies (from 64 to 512 fold) were maintained during a test period following the second immunization. No severe injection site reactions were observed after immunization and all swine were healthy during the immunization period Conclusion: Recombinant EMCV VLPs could represent a new vaccine candidate to protect against EMCV infection in pig farms.