Figure 2. Humoral immune responses induced by vaccine candidates.

Groups of BALB/c mice (n = 5) were immunized subcutaneously with 10 µg D2ED III or LD2ED III two times at a two-week interval. Live dengue-2 virus (1×10⁷ FFU) was injected intraperitoneally on the same schedule. Sera were collected from mice at the indicated time points after the first immunization. (A) IgG antibodies against D2ED III were evaluated by ELISA. Preimmune sera (week 0) were collected and used to determine basal levels for comparison. (B) Antibody avidity profiles were examined by ELISA. One of two representative experiments is shown. The results are expressed as the mean ± standard deviation. Statistical significance was determined by the ANOVA Bonferroni post test. ^** p<0.01; ^*** p<0.001.