FIG. 4.
Challenge experiments in immunized mice with rNDV/SIVgag virus. rNDV/SIVgag virus (5 × 107 PFU) was inoculated once (single) or twice (double) to groups of three mice intranasally, intraperitoneally, or intravenously. Control mice were inoculated with PBS. Three weeks after the last inoculation, mice were intranasally or intravenously infected with 5 × 106 PFU of Vac/wt or rVac/SIVgag virus. Five days after vaccinia virus challenge, mice were sacrificed, and vaccinia virus titers in lungs were determined. Homogenized lungs in 1 ml of PBS were used to determine vaccinia virus titers in CV-1 cells.