Extended Data Fig. 1. PD-1 + IL-2 combination therapy synergistically expands functional LCMV-specific CD8⁺ T cells that mediate viral control during chronic infection.

a, Experimental setup for panels b-e. Mice chronically infected with LCMV were either left untreated, or treated with anti-PD-L1 antibody alone (200 μg i.p., every 3 days), IL-2 therapy alone (15,000 IU i.p., twice daily), or the combination therapy for 2 weeks. b, Numbers of D^bGP33⁺ CD8⁺ T cells in the indicated tissues and blood (per 1 × 10⁶ PBMCs). c, d, Spleen cells were stimulated with pools of LCMV-specific peptides for 5 h and analyzed by intracellular staining of cytokines (c) and degranulation (d). e, Viral titre in the indicated tissues. f, Experimental setup for panels g–i. LCMV chronically infected mice were either left untreated, or treated with combination therapy, or combination therapy plus anti-CD8 depleting antibody (200 μg i.p., every 3 days) for 2 weeks. g, Viral titre in the indicated tissues of the three groups of mice. h, i, Correlation between viral titre in the various tissues and the number of CD8⁺ T cells (h), or LCMV-specific (D^bGP33⁺ and D^bGP276⁺) CD8⁺ T cells (i). Results were pooled from 3–13 experiments (b–e) with n = 25–32 (spleen), n = 14–18 (liver), n = 7–8 (lung), and n = 20–33 (blood) (b), with n = 28–38 (IFNγ⁺), n = 28–38 (IFNγ⁺TNFα⁺), n = 16–23 (IFNγ⁺IL-2⁺), and n = 18–25 (CD107a⁺) (c), and with n = 16–19 (spleen), n = 12–15 (liver), and n = 13–14 (lung) (e) per group or pooled from 2–3 experiments with 2–4 mice per group in each experiment (g-i). Data are presented as geometric mean and 95% CI (b–d), mean and SD (e, g), or linear regression line and Pearson correlation coefficient (two-tailed) (h, i) with p values. Statistical comparisons were performed using Kruskal-Wallis test with Dunn’s multiple comparison test (b–d) or one-way ANOVA with Tukey’s multiple comparison test (e). Untx, untreated.