Partial protective effect of inactivated Japanese encephalitis vaccine on lethal West Nile virus infection in mice.

The effect of mouse brain-derived, inactivated Japanese encephalitis (JE) vaccine on West Nile virus (WNV) infection was examined using a murine model. Mice were immunized with JE vaccine twice and challenged with lethal doses of WNV. When mice were intracranially challenged with WNV, none of the immunized mice were protected. When mice were intraperitoneally challenged, the immunized mice were protected at higher immunization levels. Cross-reactive neutralizing antibodies to WNV were induced by immunization with JE vaccine; however, the levels were much lower than those to JEV. These results indicate that the currently available mouse brain-derived inactivated JE vaccine can induce partial protective immunity to WNV in mice.