Der p 1

Mice were sensitized to allergic responses by intranasal administration of papain, an allergenic protease or HDM extract (Der p 1, Greer Laboratories)^{28 (link)}. In brief, mice were anaesthetized with isoflurane (Isothesia, Henry Schein Animal Health) and 10 μg of papain (5125, Calbiochem) in 30 μl of PBS was administered for 2 consecutive days (day 0 and 1). For HDM, mice were sensitized by 25 μg (protein content) in 25 μl of PBS for 3 days (days 0, 1 and 2), and challenged after two weeks with 5 μg (protein content) in 25 μl of PBS for 3 days (days 14, 15 and 16)^{28 (link)}. The mechanical properties of the respiratory system were measured using a rodent lung function testing system (FlexiVent, SCIREQ). In brief, the mice were anaesthetized by intraperitoneal injection of sodium pentobarbital (100 mg kg⁻¹, Esconarkon, Streuli Pharma), then tracheotomized and mechanically ventilated followed by intraperitoneal administration of pancuronium (0.08 mg kg⁻¹, Hospita). Airway constriction was induced by administering increasing aerosolized doses (0.3125 kg⁻¹, 12.5 kg⁻¹ and 50 mg kg⁻¹) of methacholine chloride (Sigma-Aldrich). Airway resistance was calculated from forced-oscillation measurements of changes in pressure, volume and flow.

Balb/c mice were administered 25 μg House Dust Mite (HDM) extract (10.17 μg/l DerP1, 9 EU/ endotoxin content; Greer Laboratories) in 50 μl sterile PBS intranasally (i.n.) three times per week for up to 3 weeks. Control mice were administered 50 μl sterile PBS i.n. at analogous time points. All mice were culled 24 hours post the final dose of HDM or PBS.