Figure 5.

The effect of pre-existing immunity on the immune responses induced by the MV-vectored dengue vaccine. The immunization schedule is shown at the top of the figure. Groups of hCD46 mice were pre-infected with 1 ×10⁶ pfu of rMV-EGFP, 1 ×10⁶ pfu of DENV-3 or a PBS-treated naïve control. After three weeks, all mice were immunized with rMV-TDV by ip injection and boosted 4 weeks later. (A) Specific T-cell responses to either MV or DENV were measured one week after a single immunization by ELISPOT assay and presented with the mean and SD of SFC per million spleen cells. The specific IgG titers to MV (B) or DENV-1 to 4 (C-F) were determined by ELISA. The detection limits for the ELISPOT assay or ELISA are indicated in a dashed line. Mann-Whitney t-tests were used for statistical analyses, and the significance compared with the naïve control is shown.