Fig. 4.

Immunogenicity of SIVmac239 Gag polypeptide expressed by rMRV in mice. (A) Representative flow cytometry plots of splenocytes collected from C57BL/6 mice immunized with an adenovirus 5 vector expressing SIVmac239-Gag (Ad5-Gag) (1 × 10⁹ pfu of purified virions), rMRV WT (1 × 10⁷ pfu of purified virions), or rMRV L1/gag900w/2A/5′66w+M1/3′153 (rMRV-Gag) (1 × 10⁷ pfu of purified virions). After collection, the splenocytes were restimulated with no peptide, AL11 peptide, or KV9 peptide, as indicated, followed by staining for surface CD8 (x axis) and intracellular IFNγ (y axis). (B) T-cell responses in immunized mice were quantitated using splenocyte recoveries and percentages of IFNγ⁺CD8⁺ T cells after stimulation with no peptide (white bars), AL11 peptide (black bars), or KV9 peptide (gray bars). Error bars, SD from the mean (mock: n = 2; Ad5-Gag: n = 4; rMRV-WT: n = 6; rMRV-Gag: n = 6). Significance was determined by one-way unpaired t-test, and P values are shown for rMRV-Gag relative to rMRV-WT.