Figure 6.

ICOS is required for the production of IL-10 by Foxp3⁺ Treg cells, but not Foxp3⁻ Teff cells. WT (circles) and ICOS^−/− (squares) mice were infected with H. polygyrus and flow cytometry was used to quantify the intracellular production of IL-10 by (A, C) CD4⁺Foxp3⁺ Treg cells and (B, D) CD4⁺Foxp3⁻ Teff cells isolated from the (A, B) LP and (C, D) MLN at day 7 pi. Data shown are pooled from two (A and B) or three (C and D) independent experiments. Open symbols represent naïve mice and closed symbols represent infected mice. Lines denote mean values. *p < 0.05 (Tukey HSD, ANOVA using combined data from two or three experiments).