The lungs were perfused with 5 ml of PBS containing 10 U/ml heparin (Sigma-Aldrich, St. Louis, MO) through the right ventricle using a syringe fitted with 25-gauge needle. The lungs were then removed and placed in RPMI medium supplemented with glutamine, gentamicin, penicillin G, and 10% FBS (HyClone, Logan, UT). The tissue was then processed through a steel screen to obtain a single-cell suspension, and particulate matter was removed by passage through a 70-μm Falcon cell strainer (BD Labware, Franklin Lakes, NJ). Freshly explanted BAL fluid or lung cells were purified by density gradient centrifugation and stained in PBS-3% FBS-0.09% NaN 3 using fluorochrome-conjugated antibodies. The antibodies used were anti-CD4 (clone RM4-5), anti-CD44 (clone IM7) or anti-CD43 (clone 1B11). Both antibodies were purchased from BD PharMingen (San Diego, CA). After staining, cells were fixed in PBS-2% (wt/vol) paraformaldehyde, and events were acquired using a FACSCalibur flow cytometer (BD Biosciences, San Diego, CA). To enumerate the number of cytokine-producing cells, intracellular cytokine staining was performed as described elsewhere (21) . In brief, 2×10 6 freshly explanted lung lymphocytes were cultured in a culture tube. Cells were left untreated or stimulated with 10μM G (183-195) peptide (WAICKRIPNKKPG) and then incubated for 5 h at 37 o C in 5% CO2. Brefeldin A (5μg/ml) (Sigma-Aldrich) was added for the duration of the culture period to facilitate intracellular cytokine accumulation. Cells were then stained for surface markers, washed, fixed, permeabilized with fluorescence-activated cell sorter buffer containing 0.5% saponin (Sigma-Aldrich, Seoul, Korea), and stained for cytokines. The antibodies used were anti-IFN-γ (clone XMG1.2) or anti-IL-17A (TC11-18H10.1). Dead cells were excluded on the basis of forward and side light scatter patterns. Data were collected using CELLQuest software (BD Biosciences) and analyzed with CELLQuest and WinMDI version 2.9 software (Scripps Research Institute, La Jolla, CA). Lung supernatants were also collected for analysis with the FlowCytomix (eBioscience), according to the protocol. Kits containing antibody beads (IL-4, IL-5, IL-6, IL-10, IL-13) were used to measure cytokine levels in each of the samples. 