Female C57BL/6 mice at 8–10 weeks of age and free of murine-specific pathogens were obtained from the Orient Bio Inc. (Seongnam, Korea). In addition, Cas9 RNA-guided endonuclease (RGEN) PI3K-δ KO mice (Macrogen, Inc., Seoul, Korea) were used, and they were interbred and maintained up to 8–10 weeks of age in pathogen-free condition at Macrogen, Inc. They were housed throughout the experiments in a laminar flow cabinet and maintained on standard laboratory chow ad libitum. All experimental animals used in this study were under a protocol approved by the Institutional Animal Care and Use Committee of Chonbuk National University (CBU 2014-00054). Each animal experiment was performed using 6 mice per group. When using Cas9 RGEN PI3K-δ KO mice, 4 mice were allocated to each experimental group. For the HDM-induced asthma model, mice were sensitized intratracheally with HDM extract (100 μg, Dermatophagoides pteronyssinus; GREER laboratories, Lenoir, NC, USA) on days 1 and 7. On day 14 after the initial sensitization, the mice were challenged intratracheally with 100 μg of HDM extract in saline (or with saline as a control). Bronchoalveolar lavage (BAL) was performed 48 hours after the challenge as previously described.11 (link)