HBEGF and Abnormality of the skin: To test the functional role for DCs in the IL-23-induced skin changes, we depleted the CD11c-expressing cells by injecting diphtheria toxin (DT) into mice expressing a diphtheria toxin receptor (DTR)-enhanced green fluorescent protein (EGFP) fusion protein under control of the Itgax (CD11c) promoter (CD11c-DTR; Fig. 2a).