Background：Dendritic epidermal T cells(DETC) are skin specific members of the epithelial γδ-T cell family that reside normally in mouse epidermis. Although the mechanisms of antigen recognition by αβ-T cells have become better defined, the physiological role of the γδ-T cells and ligands they recognize are still poorly understood. Object：In the present study we sought to elucidate the antigen specificity and whether the DETC recognize transformed keratinocyte derived antigen. Method：We used a DETC and TCR(-) DETC which were obtained by 1600R γ-irradiation and sorting, in addition to transformed keratinocyte cell lines. We performed coculture experiments of DETC/transformed keratinocyte cell lines to detect direct evidence that DETC recognize the keratinocyte-derived antigen. Result：1. TCR negative variants of DETC do not respond to concanavalin(Con)-A, but respond to phobol myristate acetate(PMA)/ionomycin. 2. PAM 212, UV-irradiated PAM 212 and heat shocked PAM 212 cells stimulate DETC. PAM 212 cells could perform as stimulator of DETC even in the absence of stress signal. 3. UV irradiated XB2 cells stimulate DETC, but XB2 and heat shocked XB2 cells could not stimulate DETC. 4. DETC do not respond to fibroblast, UV-irradiated fibroblast and heat shocked fibroblast 5. TCR negative variants of DETC are no longer stimulated by PAM 212 cells, suggests that PAM 212 cells mediate their effects through the TCR Conclusion：The above results strongly suggest that DETC recognize specific, transformed and stressed keratinocyte-derived antigens and may play a role as an immune surveillant for cellular damage. Therfore, DETC may play critical roles during the induction of immune reaction in the skin. (Korean J Dermatol 2000;38(11)：1444~1452)