Immunoregulation by Cytolytic Pathways,Mucins and Progesterone at the Maternal-Fetal Interface

The maternal-fetal interface of pregnant mammals is characterized by a sensitive balance between hormones, cytokines, humoral factors and cellular interactions. Progesterone activity leads to the transformation of endometrial cells into the decidual phenotype and ensures the integrity of the maternal-fetal interface during trophoblast invasion and placenta maturation. Communication between the genomic and non-genomic progesterone-regulated signaling pathways could be of critical importance for the establishment of a correct endocrine-immune interaction in the human endometrium during the establishment and maintenance of pregnancy. Cytolytic cells (NK and T lymphocytes) infiltrating the decidua of pregnancy are heavily equipped with cytolytic molecules perforin and granulysin. These molecules have very important role(s) in the maternal tolerance of fetoplacental unit, control of trophoblast invasion, defense against infective agents and malignancies, as well as immunomodulatory functions. Mucins MUC-1 and TAG-72 are important features of secretory phase decidual reaction, while their disappearance from the surface of the epithelial cells enables apposition, adhesion and infiltration of high quality blastocysts at the precise area at the time of the implantation. Muc-1 and TAG-72 induce antiinflammatory orientation of the decidual antigen presenting cells.