Administration of rIL-22 reduces AHR and airway inflammation.

<p>Airway responsiveness (panel A), cell counts in BAL fluid (panel B) and lung tissue inflammation and goblet cell metaplasia (panel C) were assessed in mice 48 h after the last airway challenge. Mice which were sensitized and challenged (sens/chall, n = 12) showed increased airway reactivity and numbers of eosinophils in BAL fluid compared to challenged only mice (chall, n = 5), where no eosinophils were detectable. Intranasal treatment of sensitized and challenge animals with 0.1 µg recombinant IL-22 (IL-22 0.1 µg, n = 12) showed little effects on AHR and inflammation. In contrast, mice treated with either 1 µg (IL-22 1 µg, n = 12) or 10 µg (IL-22 1 µg, n = 12) of recombinant IL-22 showed decreased AHR and number of eosinophils in BAL fluid. Means±SEM are given, *p<0.05 compared to sens/chall. <i>Panel C:</i> Tissue inflammation was evaluated 48 hrs following the last challenge using hematoxylin and eosin staining (HE) and PAS staining for goblet cells in challenged only mice (chall), non-treated sensitized and challenged mice (sens/chall) and sensitized and challenged animals treated with 10 µg of recombinant IL-22 (rIL-22). Final magnifications 100× and 400× for inserts. <i>Panels D and E:</i> Levels of IL-13 (panel D) and CCL17 (panel E) were measured in BAL fluid by ELISA 48 h after the last challenge. Means±SEM of challenged only mice (chall, <i>n</i> = 5), non-treated sensitized and challenged mice (sens/chall, n = 12), and sensitized and challenged mice treated with 0.1 µg (0.1 µg IL-22, n = 12), 1 µg (1 µg IL-22, n = 12) and 10 µg (10 µg IL-22, n = 12) of rIl-22, respectively. Mean±SEM are given. * p<0.05 compared to sens/chall and 0.1 µg IL-22.