Abstract: In order to determine theefect of novel immunosuppressant-FK506 on dendritic epidermal Tcells(DETC)of mice,we sequentially investigated the density of DETC after the administration of FK506 in vitro and vivo,using indirect immunofluorescencete chnique with anti-Thy-1 McAb.The results showed that:(1)The density of DETC significantly decreased in a dose-dependent manner 2～7 days after intra-peritoneal injection with FK506 at 0.32mg·kg·d and 0.96mg·kg·drespectively (P<0.05,P<0.01);(2)The density of DETC in skin graft of mice decreased 2hours and 10 hours after treatment with FK506 at 1μg/ml and 10μg/ml respectively(P<0.05,P<0.01).It suggested that the immunosuppressiveaction of FK506 in miceskinmay,at least in part,be related to the change of the function of DETC.

Key words: FK506, Tcels, dendritic epidermal