Supplementary Figure 1: Bystander inflammation conditioned T_reg cells have normal functional suppressive activity and ex vivo phenotype.

WT Balb/c mice were treated with polyI:C (pIC) or PBS (ctr) via i.p. injection for two consecutive days. (a) Splenocytes were assessed for frequency (left panel) and total number (right panel) of intracellular Foxp3⁺ CD4 T cells seven days after the first injection. Each symbol represents an individual mouse. P-values by student’s two-tailed t-test, *p<0.05, **p<0.01. (b-d) In vitro T cell suppression assay with T_REG isolated from ctr and pIC-treated mice. Activation of effector CD4⁺ T cells as shown by (b) proliferation, (c) CD25 expression (mean florescence intensity, MFI), and (d) intracellular T-bet expression. Bar graph depicts mean plus SEM, data representative of two independent experiments, n=2 mice per group. (e) Splenocytes from pbs- and pIC-treated mice were stimulated ex vivo and intracellular cytokine expression was assessed. (f) Diagram depicting experimental approach for acute primary airway inflammation. Following intranasal treatment with pIC or PBS, mice were primed intranasally with TSLP and OVA, then challenged with OVA one week later, see Materials and Methods for detailed description. (g) Total pulmonary neutrophil counts from mice treated as described in main figure 1, each symbol represents an individual mouse.