Study on the induction of human tolerogenic dendritic cells by curcumin

Objective:To observe the induction of human tolerogenic dendritic cells by curcumin.Methods:Peripheral blood mononuclear cells were isolated from human peripheral blood by Ficoll-Hypaque density gradient centrifugation,and then cultured in the medium including rhGM-CSF and rhIL-4 for 6 days.There are four groups:①immature DC group(imDC group),②curcumin group(Cur group),③curcumin and lipopolysaccharide group(Cur+LPS group),④lipopolysaccharide group(LPS group).The DCs were analyzed by flow cytometry for the expressions of CD80,CD83,CD86 and HLA-DR.Endocytosis of DCs to dextran was also analyzed by flow cytometry.The production of IL-12 in DC culture supernatant was determined by ELISA.The proliferation of allogenetic T cells was detected by MTT method.Results:Curcumin suppressed the expression of costimulatory molecules(CD80,CD83,CD86) and the antigen presenting molecule(HLA-DR) in a dose-dependent manner.There was no marked difference in the surface molecules expression of Cur+LPS group as compared with immature DCs.The positive rate of dextran uptake of Cur+LPS group was remarkably higher than in LPS group(P0.05).While DCs in Cur+LPS group showed the decreased capacity to stimulate T cells proliferation as compared with that in LPS group(P0.05).Also the secretory amounts of IL-12 of DCs in Cur+LPS group were obviously lower than in LPS group(P0.05).Conclusion:Curcumin can inhibit the maturation of human dendritic cells,and lead to the tolerogenic dendritic cells.