Figure 5.

ICOS deficiency increases Treg-cell apoptosis, but not proliferation, during H. polygyrus infection. (A, B) WT (circles) and ICOS^−/− (squares) mice were infected with H. polygyrus and the in vivo uptake of BrdU by (A) CD4⁺Foxp3⁺ Treg cells and (B) CD4⁺Foxp3⁻ Teff cells from the MLN quantified on days 7–21 pi. (C and D) Ex vivo percentage of MLN (C) CD4⁺CD25⁺ Treg cells and (D) CD4⁺CD25⁻ Teff cells positive for Annexin V on day 7 of H. polygyrus infection is shown. 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. Significant effect of strain (*) and infection (§) (p < 0.05, Tukey HSD). (A and B) ANOVA was performed using combined data from two experiments. (C and D) ANOVA was performed using combined data from three experiments with experiment as a random variable.