Objective: To study the effect of emodin on the differentiation, maturation and function of human dendritic cells (DC) in vitro.
Methods: Cells 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.
Results: The 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.
Conclusion: Emodin could evidently suppress the maturation and immune stimulating function of DCs during their in vitro conversion process.