Immunization with DIII-C-AP205 protects from lethal WNV infection. A Induction of neutralizing antibodies. Groups of female C57BL/6 mice (n = 8) were immunized subcutaneously on days 0, 14 and 28 with 50 μg DIII-C-AP205 either in the absence or presence of Alum as adjuvant or with 50 μg AP205 VLPs in the absence of adjuvant. A fourth group was immunized once with 50 μg DIII-C-AP205 in Alum on day 28. Virus-neutralizing titers of individual sera were measured on day 42. The dashed line indicates the detection limit. Shown are individual titers and group means. B Protection from WNV challenge. Two weeks after the last vaccine injection mice were challenged with a lethal dose of WNV (arrow). Statistical significance of differences in survival curves was calculated by log-rank test using GraphPad-Prism (***p < 0.001 vs. 3xAP205 control). p.i.= post infection C and D Viral titers were determined 3 and 7 days post infection (p.i.) in blood of infected animals. Shown are individual titers and group means. The Mann-Whitney test was used to assess statistical significance (**p < 0.01, ***p < 0.001 vs. 3xAP205 control).