ObjectiveTo explore the effect of high dose γ-irradiation on the phenotype and function of dendritic cells (DCs) and to study the underlying mechanism of irradiation-induced immunosuppression. MethodsGM-CSF and IL-4 were used to generate DCs, which were then subjected to 0, 10, 20, and 30 Gy γ-irradiation. After 24 h irradiation DCs were treated with lipopolysaccharide for maturation. Then Transwell assay was used to determine the migration capacity of DCs, flow cytometry was used to detect the surface molecules on DCs (CD80, CD86, MHC-Ⅱ, and CCR7). Cytokines secretion (IL-6, IL-10, and PGE2) was determined by ELISA. ResultsHigh dose γ-irradiation showed no influence on the phenotypes of DCs, but inhibited the migration of DCs towards CCL19. Moreover, the irradiation down-regulated CCR7 expression and decreased the secretion of IL-6, IL-10, and PGE2. Conclusion High dose γ-irradiation can inhibit DC migration by reducing CCR7 and inducing apoptosis. Moreover, it can also reduce the cytokine secretion, which provide a theoretical base for irradiation-induced immune suppression.