IL-15-deficient mice have reduced inflationary CD8 T cell maintenance.

(A) Naïve C57BL/6 mice and IL-15^-/- mice were infected i. v. with MCMVΔm157. Percentages of M38-specific CD8 T cells of total lymphocytes were longitudinally measured in the blood. (B) Total number of M38-specific CD8 T cells and (C) percentages of M38-specific CD8 T cells of total lymphocytes in lungs, spleen and LNs at 62 dpi are shown as mean + SEM of n = 8–10 mice representative from three independent experiments. (D) Viral titres of infected C57BL/6 and IL-15^-/- mice are shown as mean of n = 2–4 mice representative of two independent experiments. (E) Mean fluorescence intensities of Bcl-2 on M38-specific CD8 T cells are shown as mean + SEM of n = 8–10 mice representative from three independent experiments. (F) Percentage of Ki67⁺ of M38-specific CD8 T cells in lungs, spleen and LNs at 62 dpi are shown as mean + SEM of n = 8–10 mice representative from three independent experiments. (A-E); **p<0.01; ****p<0.0001. Statistical analyses were performed using the non-parametric Mann-Whitney U test.