Inhibitory Effect Of1,25(OH)₂D₃on The Maturation Of Human Dendritic Cells And DC-mediated Immune Tolerance In Vitro

Objective:This study was armed to investigate the effect of1,25(OH)2D3on the differentiation, maturation of human dendritic cells(DCs) in vitro,and then exlopre the possible mechanise about DC-mediated immune tolerance.Methods:Human peripheral blood mononuclear cells(PBMCs) were induced to dendritic cells in vitro.The study group DCs were cultured with different concentrations1,25(OH)2D3whlie the control were added with the same amount of absolute alcohol.The expression of co-stimulatory on DCs were analyzed by flow cytometry. T cell proliferation induced by DCs was assessed by MTT.The expression of IDO protein were determined by western blot.Results:(1) Compared to the control group, the expression of CD80,CD83and CD86on DCs in study group were significantly down-regulated(p<0.05),while CD la were up-regulated (p<0.05). The percentage of expressing in10"10mol/L1,25(OH)2D3group were(35.91±10.19)%,(27.15±11.64)%,(61.49±8.41)%,(40.43±9.83)%;10"9mol/L1,25(OH)2D3group were(32.04±8.3)%,(23.65±10.13)%,(54.45±9.29)%,(43.81±11.53)%;10-8mol/L1,25(OH)2D3group were(19.44±5.36)%,(12.64±4.65)%,(37.13±5.92)%,(46.57±10.91)%respectively,while the control group were (45.49±6.59)%,(36.77±7.42)%,(73.20±11.86)%,(29.36±13.34)%.(2)Compared with the control group,1,25(OH)2D3-treated DCs exhibited a markedly reduced ability to stimulate allogenic T cells proliferation.(3)The expression of IDO protein were up-regulated. Conclusion:1,25(OH)₂D₃efficiently inhibit the maturation of dendritic cells andDC-mediated T cell proliferation,which may be related to the up-regulation of IDO proteinexpression.