Overproduction of IL-18 in lungs increases Th1 and Th2 cytokines, and airway hyperresponsiveness.

<p>(A) The concentrations of IFN-γ, IL-13, IL-1β, and eotaxin in the bronchoalveolar lavage fluids (BALFs) were measured by specific ELISA kits. (n = 4 to 6 per each group) *: p<0.05 (B) On day 19, BALF cells were isolated from OVA-sensitized and challenged mice. Three-color analysis was performed for intracellular cytokine staining. Isolated BALF cells were stained with FITC-anti-mouse CD4 mAb, PE-anti-mouse IL-13 mAb, PC7-anti-mouse IFN-γ mAb, and/or control isotype matched mAbs, as reported previously <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0054623#pone.0054623-Hoshino4" target="_blank">[14]</a>. The lymphocyte population was gated for intracellular cytokine analysis. (C) Mice were anesthetized intraperitoneally with sodium pentobarbital, and their tracheas were cannulated via tracheostomy. The mice were ventilated mechanically (tidal volume, 325 µl; frequency, 120 breaths/minute). A paralytic agent (pancuronium bromide) was administered and airway opening pressure was measured with a differential pressure transducer and was recorded continuously. Stepwise increases of acetylcholine chloride (ACh, catalog no. A-6625, Sigma–Aldrich Chemical) in 0.9% saline (0.6 to 160 mg/ml) were given by an ultrasonic nebulizer (30 seconds). The data were expressed as the provocative concentration 200 (PC200); the concentration at which airway pressure was 200% of its baseline. PC200 was calculated by log-linear interpolation for individual mice. The data were also expressed as airway resistance changes from baseline in response to 9 different doses of Ach (0, 0.625, 1.25, 2.5, 5, 10, 20, 40, 80, and 160 mg/ml). (n = 6 to 10 per each group) *: p<0.05. (D) Serum Total IgE and OVA-specific IgE concentrations were measured. (n = 5 to 12 per each group) *: p<0.05.