Fig. 4

Effect of intranasal application of EcO83-OMVs on the development of allergic airway inflammation. A Experimental setup for intranasal application of EcO83-OMVs and induction of experimental allergic airway inflammation to OVA. BALB/c mice were sensitised (i.p.) with either OVA/alum (groups Sham/OVA, OMVs 0.1 µg/OVA and OMVs 1 µg/OVA) or PBS/alum (group Sham/PBS) on days 0 and 14 and challenged (i.n.) with either OVA or PBS on days 21–24 with. Mice were treated i.n. with 30 µl of 0.1 µg EcO83-OMVs (group OMVs 0.1 µg/OVA), 1 µg EcO83-OMVs (group OMVs 1 µg/OVA) or 0.9% NaCl (groups Sham/PBS and Sham/OVA). B Airway hyperresponsiveness was measured in response to increasing doses of metacholine by whole body plethysmography. Penh = enhanced pause. C-D Differential cell counts in bronchoalveolar lavage (BAL): (C) Total cell count and (D) total numbers of macrophages, eosinophils, neutrophils and lymphocytes. E–F Representative H&E and PAS-stained lung tissue sections showing recruited inflammatory cells and mucus-producing goblet cells, respectively. G-H Quantification of histological experiments (Disease score 0–3 for PAS and 1–4 for H&E). Scale bar = 50 µm. B, C, E and F Data were analysed using a One-Way ANOVA or (D) Two-Way ANOVA followed by post-hoc Tukey’s multiple comparison test. *p < 0.5; **p < 0.05; ***p < 0.01; ****p < 0.001. n = 5/group. Data are representative of three independent experiments. Mean ± SD is shown. Significant differences between Sham/OVA and EcO83-OMVs treatment groups (OMVs 0.1 µg/OVA or OMVs 1 µg/OVA) are indicated. alum = aluminiumhydroxide; i.n. = intranasal; i.p. = intraperitoneal; OVA = ovalbumin; OMVs = EcO83-OMVs; H&E = haematoxylin and eosin; PAS = periodic acid-Schiff