Fig. 4

Asthma features are not improved by IL-15 complex. a Murine model of acute allergic asthma. Sensitization of Balb/c mice by four percutaneous applications of 500 μg of total mite extracts (HDM). For challenges, 250 μg of HDM were inoculated intranasally (IN). Four injections of the IL-15 complex and its soluble alpha receptor (IL-15 Cx) were administered intraperitoneally (IP) once daily between the two challenges. Analysis were made the day after the second challenge. b Airway resistance (RI; cmH2O/mL) in anesthetized CTL, asthmatic group (HDM) and asthmatic mice treated by IL-15Cx (HDM IL-15 Cx), in response to various concentrations (0, 5, 10, 15, 20 mg/mL) of methacholine were measured with Finepoint RC system. c Lungs were perfused with 4% paraformaldehyde solution and stained with hematoxylin and eosin (H&E) or periodic Schiff acid (PAS). Bronchial histology was performed for CTL, HDM and HDM IL-15 Cx group. Blue arrows: inflammatory peri-bronchovascular infiltrate. Black arrows: goblet cells colored with PAS. Scale = 100 μm (d) Histological sections were scored on 12 points; 4 points are devoted to morphological alteration and 8 points to inflammation (n = 3 to 7 mice per group); The PAS score was calculated on 5 bronchial sections per group, as the number of positive PAS cells (black arrows) reported to the total number of epithelial cells of this bronchus. e Eosinophils (CD3-, CCR3+) were measured in bronchoalveolar lavage fluid by flow cytometry. The cells were collected by washing the lung with 1 ml of PBS after tracheostomy.* p < 0.05, ** p < 0.01 using Mann-Whitney test. ns = not significant