Figure 3. Neutralizing antibody responses against dengue virus in mice following immunization with monovalent or tetravalent recombinant lipidated dengue envelope protein domain III.

Groups of BALB/c mice were immunized subcutaneously twice with a monovalent (10 μg recombinant lipidated dengue envelope protein domain III), a tetravalent (10 μg of each serotype of recombinant lipidated dengue envelope protein domain III) vaccine, or PBS at a 4-week interval. Serum samples were collected at the indicated time points. The neutralizing antibody capacity was determined by FRNT. The neutralizing antibody titer was calculated as the reciprocal of the highest dilution that resulted in a 70% reduction in FFU compared to control samples containing the virus alone. The neutralizing antibody titers were logarithmically transformed before statistical analyses. Statistical significance was determined by a two-tailed Mann Whitney test. *p < 0.05; **p < 0.01; ***p < 0.001. Symbols represent individual mice, and horizontal lines are mean values. The results shown are pooled from 2 experiments.