Role of decidual CD14+ macrophages in the homeostasis of maternal-fetal interface and the differentiation capacity of the cells during pregnancy and parturition

Objective: Decidual macrophages (dM Phi s) have been implicated in fetal tolerance, but little information is known regarding their differentiation capacity and interactions with T cells. The present study aimed to investigate the immunological characteristics of dM Phi s at mid and term pregnancy. Methods: The dM Phi s were analyzed for their phenotypes and cytokine production by flow cytometry and ELISA, respectively. The transendothelial trafficking model was implemented to allow the dM Phi s to differentiate. The differentiated cells from dM Phi s were also measured for their phenotypes and cytokine production with same methods. The capacity of dM Phi s or the differentiated cells from dM Phi s to stimulate allogeneic T lymphocyte proliferation was evaluated by T lymphocyte stimulation assays. T cell differentiation was determined by flow cytometry. Results: The dM Phi s in the mid-pregnancy (Mid-dM Phi s) resembled the M2 phenotype. The differentiated cells from Mid-dM Phi s had little stimulatory capacity on T cell proliferation and favored regulatory T cell differentiation. The dM Phi s at term differentiated into dendritic (DC)-like cells, stimulating T cell activation, proliferation, and differentiation into IFN-gamma-producing T cellsdecidual Conclusions: The present study suggests that the differences in phenotypes and cytokine production between Mid- and Term-dM Phi s relate to their different roles in the homeostasis of the maternal fetal interface. Mid-dM Phi s differentiate into DC-like cells with immunosuppressive properties, playing an important role in maintaining homeostasis required for a successful pregnancy. Term-dM Phi s differentiate into DC-like cells with immunostimulatory properties, likely involved in the activation of labor. The different differentiation capacities of dM Phi s in the varied pregnancy stages may be due to the placental microenvironment. (C) 2015 Elsevier Ltd. All rights reserved.