The Expression Analysis of GL50 on Monocyte-derived DCs(Mo-DCs) and Promotion of Maturation of Mo-DCs Stimulated by the Reverse Signaling of GL50

Objective To detect the GL50 expression on Mo-DCs and analyze the role of GL50 in regulation of Mo-DCs development and functions.Methods Peripheral blood mononuclear cells(PBMC) heparinized blood were isolated by Ficoll density gradient centrifugation,and PBMCs were plated into 6-well plates for 3 hours incubation.The non-adherent cells were removed and the adherent cells(monocytes) were cultured with GM-CSF and IL-4 with ICOS-L929 or mock-L929 cells for 5 days.After Mo-DCs were stimulated by anti-CD40 monoclonal antibody or TNF-α with or not stimulated with monoclonal antibody 11C4,the cells were harvested on day 2 and reacted with PE-conjugated CD80,CD86,and CD83.Then,cell surface molecules including GL50,CD80,CD83 and CD86 were detected by flow cytometry.The induced DC functions were estimated by detecting the capacity of DC uptake antigens with FITC-Dextran capturing assay.Interleukin-2(IL-2) and IL-10 were measured with the help of ELISA kits.Results We found that the expression of GL50 molecule was only detected on the surface of immature Mo-DCs,and was sharply decreased after induction of mature Mo-DCs activated by TNF-α or CD40.Furthermore, we demonstrated that reverse signal of GL50 could effectively promote the maturation of Mo-DCs in vitro as evidenced by the high expression of CD80,CD86 and CD83 as well as by with the low capacity of uptaking FITC-Dextran particle,which suggested that GL50 may be involved in the maturation of Mo-DCs.Conclusion These results suggest that reverse signal of GL50 could restrain the differentiation and maturation of monocyte-derived DC.