FIG 6.

Suppressing MHV68 reactivation during latency does not reduce MHV68-specific CD8⁺ T cell numbers or restore cytokine production in IFNAR1^−/− mice. IFNAR1^−/− mice were infected with MHV68 and administered either PBS or cidofovir (25 mg/kg) from 23 to 32 dpi. The frequency of PECs (A) and splenocytes (B) reactivating MHV68 at 32 dpi was determined by limiting-dilution reactivation assays. Shown are the means and SEM from two (PBS) or three (cidofovir) independent experiments with two to four mice per group. Dotted lines indicate the point of 63% Poisson distribution, determined by nonlinear regression, which was used to calculate the frequency of cells reactivating. Splenocytes were labeled with α-CD8, α-CD44, and p56 or p79 tetramers (C), α-CD8, α-KLRG-1, α-CD127, and p56 or p79 tetramers (D), α-CD8, α-PD-1, and p56 or p79 tetramers (E), or α-CD8, α-IFN-γ, and α-TNF-α following stimulation with indicated peptides (F) and evaluated by flow cytometry. The means ± SEM for total tetramer-positive CD8⁺ T cells (C), SLECs (D), percent PD-1⁺ (E), or percentage of IFN-γ⁺ CD8⁺ T cells also producing TNF-α (F) are plotted. Data points represent results from individual mice from three independent experiments. ns, P > 0.05; *, P ≤ 0.05; **, P ≤ 0.01; ***, P ≤ 0.001 (paired, two-tailed Student's t test).