FIGURE 1.

Extracellular, but not nuclear IL-33 contributes to CD8⁺ T-cell responses. (a and b) Spleen cells were isolated from naïve WT and IL-33^−/− mice, followed by adoptively transferring them into CD45.1 recipient mice. (c and d) Spleen cells were isolated from naïve CD45.1 mice, followed by adoptively transferring them into WT and IL-33^−/− recipient mice. The number of transferred cells was 1 × 10⁷ for each mouse. Animals were infected with LCMV (2 × 10⁶ FFU/mouse) 1 day after cell adoptive transfer, and killed at 7 days post-infection. Lymphocytes were prepared from spleens and stimulated with viral peptides GP33 (5 μg/ml) in the presence of Brefeldin A for 5 h, followed by surface marker and intracellular cytokine staining. The transferred cells in recipient mice were gated first according to CD45.1 and CD45.2 markers. The data are shown as mean ± SEM of n = 3–5 mice/group from single experiments and are representative of at least three experiments performed. A two-tailed Student’s t test was used for statistical analysis. *p < 0·05; **p < 0·01; NS, no significant difference