FIG. 1.

CD8⁺ T-cell kinetics following DNA immunization or virus infection. Mice were infected with LCMV or vvNP or immunized with pCMVNP 7, 11, 15, 20, or 30 days prior to the assay. Splenocytes were harvested, stimulated for 5 h with peptide antigen, and then stained for IFN-γ and CD8. A total of 5 × 10⁵ events were acquired on a flow cytometer, and live cells were analyzed for expression of CD8 and IFN-γ. The values shown (plotted on a log₁₀ scale) reflect the average number of peptide-specific CD8⁺ T cells expressed as a percentage of total CD8⁺ T cells present in the spleens ± standard deviation (three mice/group at each time point).