Fig. 4.

Recruited Tregs are necessary to control CD4 T cells response in the airways. BALB/c WT or DEREG mice or were vaccinated with FI-RSV and infected 3 wk later with RSV i.n. (day 0). When indicated, mice were treated i.n. with a mixture of 0.5 µg of both CCL17 and 22, or PBS on day 2 after RSV infection or/ and depleted of Tregs by diphtheria toxin injections on days −2, −1, and 2. All mice were killed on day 4 and BAL cells obtained. (A) Daily weights as percentage of original weight. (B) Frequencies of CD4 T cells and Tregs by flow cytometry. (C) Ratio of numbers of Tregs to CD4 T cells. One representative study of two independent experiments with five mice per group is shown. Results are presented as means ± SEM. The significance of results between the groups was analyzed by two-tailed, unpaired Student t test. *P < 0.05, **P < 0.01, ***P < 0.001.