Figure 1.
Targeted IL-22 expression in the airway epithelial cells.
(A) IL-22 mRNA expression in the lung of Tg(+) mice after being given doxycycline (Dox) water for 4 weeks compared to Tg(−) mice. (B) IL-22 protein in the BAL samples expressed by airway epithelial cell was measured by ELISA. Both SPC-IL-22 and CC10-IL-22 Tg(+) mice showed much higher levels of IL-22 compared to Tg(−) mice (P<0.0001). (C) Identification of localization of IL-22 expression by IHC in the airway epithelial cells. In CC10-IL-22 mice IL-22 was mainly expressed in the large airways, whereas in SPC-IL-22 mice, mainly in the small airways.
Figure 2.
Activation of p-STAT3 by IL-22 in the lung of Tg(+) mice.
(A) Phospho-STAT3 protein expression activated by IL-22 in the airway epithelial cells of IL-22 Tg(+) mice and compared to background level in Tg(−) mice using immunofluorescence (IF). (B) Phospho -STAT3 protein expression in the lung tissue of IL-22 Tg(+) and Tg(−) mice detected by Western blot using anti-p-STAT3 antibody. (C) Phospho-STAT3 protein expression in the lung tissues of OVA-stimulated IL-22 Tg(+) and Tg(−) mice detected by Western blot.
Figure 3.
IL-22 alleviated OVA-induced eosinophilic inflammation in the lung.
(A) High levels of IL-22 cytokine were seen in the BAL of PBS and OVA-stimulated IL-22 Tg(+) mice without difference between the two groups (P>0.05). When compared to Tg(−) mice, IL-22 concentrations in the BAL of Tg(+) mice were much higher than that in PBS and OVA-stimulated control groups (P<0.0001). (B, C) BAL total cell and differentials counts showed that OVA-stimulated IL-22 Tg(+) group had a much higher percentage of eosinophils compared to OVA-stimulated Tg(−) mice (P<0.0001), but there is no difference in the total cell counts (P>0.05). (D) Lung histology of OVA-induced allergic asthma in SPC-IL-22 Tg(+) mice and Tg(−) mice, H&E, IHC for MBP, and Alcian blue staining showed that OVA-induced IL-22 Tg(−) group had much more severe airway inflammation compared to OVA-induced IL-22 Tg(+) group.
Figure 4.
IL-22 attenuated airway hyperresponsiveness (AHR).
(A, B) Invasive PFT of OVA stimulated IL-22 Tg(+) and Tg(−) mice was assessed (FlexiVent, SciQuest). Lung resistance at baseline and in response to increasing concentrations of methacholine (MCh) through inhalation was recorded and analyzed (*P<0.05). The number of animals used in each group was as indicated. Data represented as Mean±SEM. OVA-induced IL-22 Tg(+) mice showed significantly lower lung resistance compared to OVA-induced IL-22 Tg(−) mice.
Figure 5.
Serum immunoglobulin levels in OVA-induced allergic asthma in IL-22 Tg(+) (SPC-IL-22) and Tg(−) mice.
Serum samples from IL-22 Tg(+) and Tg(−) mice were collected 48 hours after last OVA challenge. Immunoglobulins, including total and OVA-specific IgE, IgG1 and IgG2a were measured by ELISA and analyzed by one-way ANOVA. Data from individual animals were plotted. Both IL-22 Tg(+) and Tg(−) group showed much higher level either in total or in OVA-specific IgE, IgG1 and IgG2a than PBS treatment groups (P<0.01). But there is no difference between IL-22 Tg(+) and Tg(−) groups (P>0.05).
Figure 6.
Effect of IL-22 (CC10-IL-22) on cytokine and chemokine production in OVA-induced allergic asthma.
Th1 cytokine, IFN-γ, and Th2 cytokines, IL-4 and IL-13, Th17 cytokine IL-17A, and chemokine eotaxin in the BAL were measured by ELISA. The number of animals in each group was indicated and data were shown as Mean±SEM. **P<0.01 (unpaired Student t-test).
Figure 7.
Effect of IL-22 (SPC-IL-22) on OVA-induced systemic and local immune responses.
Splenocytes and lymphocytes from peribronchial draining lymph nodes (DLN) from IL-22 Tg(+) and Tg(−) mice after OVA challenge were cultured and stimulated with medium control, OVA or CD3/CD28. Th1 cytokine, IFN-γ, and Th2 cytokine, IL-13 in the supernatant were measured by ELISA. The number of animals used in the experiments was indicated and data were shown as Mean±SEM. *P<0.05 and **P<0.01 (unpaired Student t-test).