Mice chronically infected with were either left untreated, or treated with anti-PD-L1 antibody alone, IL-2 therapy alone, or combination therapy. a, Numbers of Foxp3+ CD4+ regulatory T cells (Tregs) in the indicated tissues. b, Numbers of LCMV-specific (DbGP33+ and DbGP276+) CD8+ T cells. c, Ratio of LCMV-specific (DbGP33+ and DbGP276+) CD8+ T cells vs. Foxp3+ CD4+ T cells (CD8+ effector/CD4+ Treg ratio). d, Correlation between viral titre and CD8+ effector/CD4+ Treg ratio in the various tissues. Results were pooled from 5–8 experiments with n = 2–4 per group in each experiment. Data are presented as geometric mean and 95% CI (a, b), mean and SEM (c), or linear regression line and Pearson correlation coefficient (two-tailed) (d) with p values. Statistical comparisons were performed using Kruskal-Wallis test with Dunn’s multiple comparison test (a–c). Untx, untreated.