Immunization with pseudotype baculovirus expressing envelope protein of Japanese encephalitis virus elicits protective immunity in mice.

BACKGROUND

Japanese encephalitis (JE) is a serious infection disease throughout southern and eastern Asia. The design and development of safer and more efficacious vaccines against Japanese encephalitis virus (JEV) is a matter of high priority. Recently, baculovirus pseudotyped with vesicular stomatitis virus glycoprotein was described as an attractive gene-delivery vehicle in mammalian cells and a potential vector for vaccine development. In the present study, we constructed recombinant pseudotype baculovirus encoding the Japanese encephalitis virus (JEV) envelope (E) protein and demonstrated that it could elicit high protective immunity in mice.

METHODS

Recombinant pseudotype baculovirus (BV-G-E) was generated by inserting JEV E gene fragment into pFastBac-VSV/G vector. BALB/c mice were immunized with BV-G-E and challenged with JEV wild-type strain. The neutralization antibody, interferon (IFN)-gamma expression and release, and survival rate were analysed and compared with the group of immunized with inactivated vaccine and DNA vaccine (pc-E) encoding the same gene of JEV.

RESULTS

We demonstrated that intramuscular injections of BV-G-E at various doses into mice produced higher levels of JEV-specific neutralizing antibodies, IFN-gamma and better protective efficacy against a lethal challenge with JEV than that of pc-E. Furthermore, BV-G-E could elicit a higher level cellular immunity response and provide equal protective efficacy against JEV challenge compared to inactivated vaccine.

CONCLUSIONS

Our data demonstrate that BV-G-E elicited higher levels of protective immunity than DNA vaccine and that pseudotype baculovirus-mediated gene delivery can be utilized as an alternative strategy to develop new generations of vaccines against JEV infection.