[Effects of IFN-γ treatment on biological characteristics and functions of dendritic cells]

Objective To investigate the effect of IFN-γ treatment on the biological characteristics and functions of C57BL/6 murine dendritic cells (DCs). Methods In the process of DC culture, 20 ng/mL IFN-γ was added in the DCs at the early (day 2) or late (day 5) stage, and on day 7, LPS was added to stimulate DC maturation. The expressions of DC surface molecules CD11c, CD80 and CD86 were determined by flow cytometry. To analyze cell functions, DCs were co-cultured with BALB/c mouse-derived lymphocyte cells. The 5, 6-carboxyfluorescein diacetate N-succinimidyl ester (CFSE) labelling was used to detect their ability to stimulate allogeneic lymphocyte proliferation and flow cytometry was used to measure their ability to induce the production of regulatory T cells (Tregs). Results Compared with the control group, the early IFN-γ treatment group had decreased DC number and inhibited cell differentiation; though there was no difference in the expression of co-stimulatory molecules, early IFN-γ treatment resisted the stimulatory effect of LPS on DC maturation, weakened the ability to stimulate allogeneic lymphocyte proliferation and enhanced the ability to induce more Tregs. Compared with the control group, the late IFN-γ treatment group showed no change in DC number and differentiation; the expressions of co-stimulatory molecules CD86 and CD80 were upregulated; the results of DC maturation and mixed allogeneic lymphocyte reaction stimulated by LPS were similar to those in the control group, but its ability to induce Tregs was stronger. Conclusion DCs treated with IFN-γ at early stage and those at late stage showed obvious difference in biological characteristics and functions.