摘要OBJECTIVE Ginsenoside metabolite compound K (CK) is a degradation product of ginsenoside in the intestine by bacteria. The anti-inflammatory and immunomodulatory activities of CK have been reported. This study investigated whether CK exerted its immunoregulatory effect through modulation of dendritic cells (DCs) function. METHODS In vivo, severity of collegen-induced arthritis (CIA), T cells and DCs subsets, phenotype of DC were assayed by flow cytometry, CCL19 and CCL21 level in lymph nodes assayed by ELISA. In vitro, bone marrow-derived DCs from normal mice were matured with lipopolysaccharide and treated with CK for 48 h. In vivo, bone marrow-derived DCs were generated from CIA mice before and 2 weeks into CK treatment. DCs were analyzed for migration, phenotype and T- cell stimulatory capacity. RESULTS CK alleviated the severity of CIA, decreased pDCs and mo-DCs, increased na?ve T cells in CIA mice lymph nodes, and suppressed CCL21 expression in lymph nodes. CK suppressed DCs migration induced by CCL21 and T cells-stimulatory capability of DC, down-regulated LPS-induced expression of CD80, CD86, MHCII and CCR7 on DCs. CONCLUSION This study elucidated the novel immunomodulatory property of CK via impairing function of DCs in priming T cells activation. These results provide an interesting novel insight into the potential mechanism by which CK contribute to the restoration of immunoregulation in autoimmune conditions.