The frequency and IFNγ production capacity of IFNγ⁺ LCMV-specific T cells are reduced in FHL2 mice receiving ST2 blockade. WT and Prf1^−/− mice were infected with LCMV, treated with either α-ST2 antibodies (open circles) or control antibodies (closed circles), and assessed on day 8 p.i. (n = 12-13 mice per group, data pooled from 3 independent experiments). Analyzed by linear mixed-effects model to account for baseline variability between experimental replicates: treatment and genotype were modeled as fixed effects, and experiment was treated as a random effect. The number symbol indicates significance of genotype (WT vs Prf1^−/−); the paragraph symbol indicates treatment (control vs α-ST2); and the asterisk indicates interaction between genotype and treatment. Representative flow plots gated on live CD90.2⁺CD8⁺ T cells (A) or CD90.2⁺CD4⁺ T cells (C), showing intracellular IFNγ expression in response to in vitro gp33 (A) or gp61 (C) peptide stimulation. Summary data showing frequencies of IFNγ⁺ LCMV-specific CD8⁺ T cells (B) and CD4⁺ T cells (D). Summary data showing median IFNγ fluorescence intensity (MFI) of CD8⁺ T cells (E) and CD4⁺ T cells (F) producing IFNγ in response to restimulation with LCMV peptides. MFI is normalized to WT control mean for each experiment. ^§§§P < .001; ^###P < .001; ^##P < .01; ^#P < .05; *P < .05.