Figure 5.

AT1a deficiency attenuates ILC2-induced lung inflammation. (A–G) AT1a^+/+ and AT1a^−/− mice were i.n. administered papain or PBS daily for 5 d. (A) Experimental procedure. (B–D) Proportions (B), cytokine production (C), and proliferation (D) of ILC2s in lungs were determined by flow cytometry. (E) Concentrations of IL-5 and IL-13 in BALF. (F) Abundance and absolute numbers of eosinophils (Eos) in BALF. (G) H&E staining of lung sections (scale bar, 100 µm). Inflammation was quantitated from all mice analyzed. (H–N) A. alternata was i.n. administered to AT1a^+/+ and AT1a^−/− mice daily for 4 d. Experimental procedure (H). Percentages of lung ILC2s (I), proliferation of lung ILC2s (J), and abundance of IL-5⁺IL-13⁺ ILC2s in lung (K) and of eosinophils in BALF (L) were determined by flow cytometry. (M) Amounts of type 2 cytokines in BALF. (N) H&E staining of lung sections (scale bar, 100 µm). (O) Bone marrow cells from AT1a^−/−mice (CD45.2) and AT1a^+/+ mice (CD45.1) were mixed at a 1:1 ratio and then transferred into recipient mice. After 4-5 wk reconstitution, the recipients were i.n. challenged with papain for 5 consecutive days. The absolute cell counts, cell proliferation, and effector cytokine production of lung ILC2s from AT1a^−/− donors and AT1a^+/+ donors are shown. (P–R) Equal number of lung ILC2s (2 × 10⁴) from AT1a^−/− and AT1a^+/+ littermates were adoptively transferred into immunodeficient NCG mice, followed by i.n. challenge of papain for 5 d. (P) Absolute number of donor-derived ILC2s. (Q) Flow cytometry plots and counts of eosinophils. (R) Concentration of IL-5 and IL-13 in NCG BALF (n = 5). Data are representative of two experiments with similar results (A–G) or from one experiment; n = 4 or 5/group (H–R). Graphical data show mean ± SEM by two-way ANOVA (B–G and M) and unpaired t test (I–R). *, P < 0.05; **, P < 0.01; ***, P < 0.001.