FIG. 2.

Comparison of the protective values of inactivated and live JEV vaccines against homologous and heterologous virus challenge in mice defective in IFN responses. Groups of 6-week-old mice were immunized with JE-VAX (three immunizations with different antigen concentrations, as indicated, given at 2-week intervals) or ChimeriVax-JE (one immunization with different virus doses, as indicated) or left untreated and challenged at 14 weeks of age with 10² PFU of JEV, MVEV, or WNV i.v. (A) IFN-α-R^−/− mice immunized with JE-VAX and challenged with JEV; (B) IFN-α-R^−/− mice immunized with JE-VAX and challenged with MVEV; (C) IFN-α-R^−/− mice immunized with ChimeriVax-JE and challenged with MVEV; (D) IFN-α/γ-R^−/− mice (deficient in both type I and type II IFN responses) immunized with ChimeriVax-JE and challenged with MVEV; (E) IFN-α-R^−/− mice immunized with ChimeriVax-JE and challenged with WNV (strain Kunjin). Mice were monitored twice daily for morbidity and mortality for 21 days.