Immature dendritic cells phagocytosing apoptotic human spleen cells treated with PUVA inhibits the maturation induced by LPS

: Objective To investigate whether lipopolysaccharide (LPS) can induce the maturation of immature dendritic cells (imDCs) which phagocytose apoptotic spleen lymphocytes. Methods Human peripheral blood mononuclear cells (PBMCs) were induced to produce DCs by interleukin 4 (IL-4) and recombinant human granulocyte macrophage colony stimulating factor (rhGM-CSF). Human spleen cells (hSPs) were isolated and treated with psoralen combined with ultraviolet A(PUVA) to obtain apoptotic PUVA-hSPs. Co-culture of imDCs with PUVA-hSPs resulted in extracorporeal photochemotherapeutic dendritic cells (ecpDCs). The imDCs and ecpDCs were collected and stimulated by 10 ng/mL LPS for 1 day. The expressions of CD11c, CD83 and CD86 were detected by flow cytometry. The level of IL-10 in the supernatants of the above cells was detected by ELISA. Results There was no significant difference in the expressions of CD83 and CD86 between ImDCs and ecpDCs. However, the positive rates of CD83 and CD86 in the imDCs stimulated by LPS were significantly higher than those in the ecpDCs treated by LPS. The level of IL-10 in imDCs culture supernatant was lower than that in ecpDCs. The level of IL-10 in LPS-stimulated imDCs was lower than that in LPS-stimulated ecpDCs. Conclusion Both imDCs and ecpDCs showed immature phenotype, but ecpDCs can inhibit the maturation of DC induced by LPS.