OBJECTIVETo study the effect of emodin on the differentiation, maturation and function of human dendritic cells (DC) in vitro.

METHODSCells isolated from human peripheral blood mononuclear cells (PBMCs) were induced to dendritic cells (DC) with recombinant interleukin-4 and recombinant granulocyte-macrophage colony stimulating factor (GM-CSF). Lipopolysaccharide (LPS) and different concentrations of emodin were added respectively in the cultured cells on the 5th and the 7th to obtain mature or immature DCs. The phenotype of DCs ( HLA-DR, CD80, CD86, CD83, CD14, CD11c) and the secretion of interleukin-12 (IL-12) were analyzed by flow cytometry, and the immune-stimulating function of DCs was evaluated by co-culture of DCs and self-T-lymphocytes.

RESULTSThe expression rate of CD80 and CD83 in the emodin group were 13.4% +/- 6.6% and 9.3% +/- 2.2% respectively; which were significantly lower than those in the control group (39.3% +/- 8.6% and 30.7% +/- 5.6%), respectively (P<0.05). IL-12 secretion of DCs was lower (1700.44 +/- 1000.21 microg/L vs 4500.60 +/- 1200.6 microg/L) but IL-10 secretion was higher (350.6 +/- 150.2 microg/L vs 230.7 +/- 90.1 microg/L) in the emodin group than in the control group (P<0.05). Mixed lymphocyte culture (MLR) examination showed that emodin could significantly inhibit the stimulation of DCs on self-T-lymphocyte proliferation.

CONCLUSIONEmodin could evidently suppress the maturation and immune stimulating function of DCs during their in vitro conversion process.