Fig. 1

β-Glucans promote Th2 allergic airway inflammation to HDM allergen both during sensitisation and challenge stages through IL-4Rα. a Timeline for HDM sensitisation and challenge of C57BL/6 mice. Mice were sensitised i.t. with HDM alone (10 μg, Greer Laboratories, Lenoir, NC, Dermatophagoides pteronyssinus (Der p1) 145.56 mcg per vial, endotoxin 31.25 EU per vial, 2.87 mg protein per vial and 11.6 mg dry weight per vial) or together with β-glucan (1×10⁷ particles ≈ 10 μg), highly purified from Saccharomyces cereviseae [8] at day 0 and 7 and challenged i.t. with HDM (10 μg) alone at day 20, 21 and 22. Control mice were sensitised and challenged with PBS at the same time-points. b Number of total leukocytes, eosinophils (Siglec-F^hiGr-1^loCD11c^lo), neutrophils (Gr-1^hiCD11b^hiF4/80^lo), monocytes/macrophages (F4/80^hiGr-1^loCD11b^hi) and T-cells (CD3⁺CD4⁺) in the BALF of mice at day 23. c Cytokine concentrations in BALF were detected by Bio-Plex Pro Mouse cytokine 23-plex Assay (Bio-Rad Laboratories Ltd, USA), according to the manufacturer’s specifications. d Haematoxylin and eosin h & e) and Periodic Acid Schiff (PAS) stained lung sections, wax embedded and formalin fixed. Bar charts (right) show quantification of the inflammation and of mucus producing goblet cells in the H&E and PAS stained sections, respectively. Scale bars represent 100 μm (H&E) and 50 μm (PAS). e Mice were sensitised and challenged as in (a), except one group of animals received dexamethasone 21-phosphate disodium salt (Sigma-Aldrich, St. Louis, MO, USA) i.p. (3 mg/kg in 100 μl) on days 20, 21 and 22. f Number of eosinophils (Siglec-F^hiGr-1^loCD11c^lo) in the BALF of wild type and IL-4Rα^−/− mice. g Number of eosinophils (Siglec-F^hiGr-1^loCD11c^lo) in the BALF of wild type and Dectin-1^−/− mice. h Proliferation (CFSE dilution frequency) or GATA3 expression (CD45.1⁺CD3⁺CD4⁺CD44^hiGATA3⁺) or RORγt expression (CD45.1⁺CD3⁺CD4⁺CD44^hiRORγt⁺) in adoptively transferred 1-Derβ specific T cells (CD45.1⁺CD45.2⁻CD3⁺CD4⁺CD44^hiCFSE⁺) in the MLN of recipient mice three days after sensitisation. For adoptive transfer, 1-Derβ TCR T cells were isolated from spleen and MLNs of naïve 1-Derβ TCR transgenic mouse, stained with CFSE and then transferred (1×10⁷ cells/mouse) to WT C57BL/6 mice 2 h before sensitisation (i.t.) with HDM alone or together with β-glucan. i Cytokine production by MLN cell suspensions isolated from mice three days after sensitisation, as above, restimulated ex vivo with HDM (15 μg) for 3 days (cytokines were detected by ELISA (eBiosciences), according to manufacturer’s instructions). Shown are the mean ± SD of pooled data from at least two independently repeated experiments. *, p < 0.05, ns, not significant