Natural killer (NK) cells are the predominant lymphocytes present in healthy rodent and human implantation sites. In the rat, the expansion, differentiation and subsequent migration of NK cells away from the developing chorioallantoic placenta coincide with the expression of a novel pregnancy- and trophoblast cell-specific cytokine, prolactin (PRL)-like protein A (PLP-A). PLP-A specifically bin...

Uterine NK (uNK) cells are abundant in human and murine uteri during decidualization. It is unclear whether precursors of uNK (pre-uNK) cells self-renew or are recruited from other sites. To assess self-renewal of pre-uNK cells, uterine segments from NK cell-competent mice were grafted orthotopically into NK/uNK cell-deficient or wild-type mice. Only in wild-type recipients did decidualized gra...

Uterine natural killer (uNK) cells remarkably increase in number after implantation. NK cells or their precursors migrate from the blood stream and contribute to the increase. However, the contribution of uNK cells present in the virgin uterus has been unclear. To elucidate this issue, we examined uterine leukocyte subsets during pregnancy in BALB/c mice. The most dramatic change was the massiv...

Precise and local control of the innate immune system within the placenta is an essential component for achieving a normal and healthy pregnancy. One of the most abundant immune cells of the placenta is a subpopulation of natural killer (NK) cells that profusely populates the uterine decidua during early pregnancy. Uterine NK (uNK) cells and trophoblast cells of the placenta communicate both di...

Background: Human peripheral blood NK cells constitutively express CD56 and CD16 antigens. Peripheral blood NK cells seem to be strongly related with decidual NK cells, and may reflect the decidual NK cell functional status. There are varied reports concerning the relationship between NK cell cytotoxicity in women with recurrent spontaneous abortion. Objective: To study NK activity in women wit...

Natural killer cells constitute 50-90% of lymphocytes in human uterine decidua in early pregnancy. Here, CD56(bright) uterine decidual NK (dNK) cells were compared with the CD56(bright) and CD56(dim) peripheral NK cell subsets by microarray analysis, with verification of results by flow cytometry and RT-PCR. Among the approximately 10,000 genes studied, 278 genes showed at least a threefold cha...

Trophoblast cell invasion into the uterine wall is characteristic of hemochorial placentation. In this report, we examine trophoblast cell invasion in the rat and mouse, the endocrine phenotype of invasive trophoblast cells, and aspects of the regulation of trophoblast cell invasion. In the rat, trophoblast cells exhibit extensive interstitial and endovascular invasion. Trophoblast cells penetr...

Natural killer (NK)-like cells have been implicated as an important component of the endometrial lymphoid cell population and have been suggested to play roles in resistance to viral infection, in abortion, and in fetal growth. Inhibition of endometrial NK cell activity may be an important aspect of successful pregnancy because of the potential for actions directed against the conceptus. The ai...

HLA-G is a nonclassical major histocompatibility complex class I molecule selectively expressed on cytotrophoblasts at the feto-maternal interface, where it may play an important role in maternal tolerance of the fetus. We provide direct evidence under physiological conditions that supports the role of HLA-G in protecting cytotrophoblasts against natural killer (NK) cytolysis in 6 semiallogenic...

OBJECTIVE To investigate whether natural killer (NK) cell and autoimmune antibody acts synergistically, by the action of autoantibodies to increase NK cell number and cytotoxicity, to decrease uterine blood flow during early pregnancy in pregnant women with a history of recurrent spontaneous abortion (RSA). METHODS Seventy-five pregnant women (between 5 and 7 weeks gestation) with a history o...