FIG. 7.

Maintenance of antiviral cellular immunity against SIV Gag in mice immunized with rNDV/SIVgag and rFlu/SIVgag viruses. Three mice per group were intranasally immunized with rNDV/SIVgag (5 × 10⁷ PFU) followed by boosting with rFlu/SIVgag (5 × 10² PFU), as indicated. Three weeks (group 1), 6 weeks (group 2), and 9 weeks (group 3) after boosting with rFlu/SIVgag virus, immunized mice were challenged with 5 × 10⁶ PFU of Vac/wt or rVac/SIVgag viruses. Group 4 included control nonimmunized animals. Mice were sacrificed 5 days after vaccinia virus challenge, and vaccinia virus titers in lungs were determined.