Whole skin cells were prepared from mouse back skin 4 (link). In brief, skin tissues were digested with a buffer containing collagenase IV, hyaluronidase, and DNase I. Skin cells were labeled with CFSE and stimulated with rIL- 23 (1ng/ml, eBioscience), rIL-1β (1ng/ml, eBioscience), or rIL-23 plus rIL-1β for 3 days. Cell proliferation and intracellular IL-17 were measured by flow cytometry. For blocking experiment, neutralizing mAbs for IL-1β (2μg/ml, eBioscience), IL-23 (12.5μg/ml, eBioscience), or matched isotype control mAbs were added. In addition, primary mouse keratinocytes (Cellntec) were stimulated with IL-1β for 6 hours and RNA were extracted for analysis of chemokine expression by real-time qPCR. For γδT cell development study, skin, thymus and BM were taken from pups before (E18 or E20) or after birth.