Liaison between natural killer cells and dendritic cells in human gestation

Abstract

A successful pregnancy relies on immunological adaptations that allow the fetus to grow and develop in the uterus, despite being recognized by maternal immune cells. Among several immunocompetent cell types present within the human maternal/fetal interface, DC-SIGN 1 dendritic cells (DCs) and CD56 1 natural killer (NK) cells are of major importance for early pregnancy maintenance, not only generating maternal immunological tolerance but also regulating stromal cell differentiation. Previous reports show the presence of NK-DC cell conjugates in first trimester human decidua, suggesting that these cells may play a role in the modulation of the local immune response within the uterus. While effective immunity is necessary to protect the mother from harmful pathogens, some form of tolerance must be activated to avoid an immune response against fetal antigens. This review article discusses current evidence concerning the functions of DC and NK cells in pregnancy and their liaison in human decidua.

How does toxoplasmosis affect the maternal‐foetal immune interface and pregnancy?

“…In normal human decidua, both immature myeloid—identifiable by their expression of DC‐SIGN (CD209)—and mature myeloid DCs coexist . In early human pregnancy, the presence of DC‐SIGN+ cells and dNK clusters indicates that the interconnection between these cell subsets is essential in pregnancy maintenance . In fact, dNK cells induce apoptosis in DC‐SIGN+ cells, constituting a mechanism of maternal‐foetal tolerance .…”

The Role of Uterine NK Cells in Normal Reproduction and Reproductive Disorders

“…In the cycling human endometrium, mature dendritic cells (DCs) are at their peak at the late secretory phase, in contrast with early pregnancy decidua, where the majority of the DCs express CD209 (DC-SIGN), a marker of immature or inactive DC (Gardner and Moffett 2003 ;Kammerer et al 2003 ;Rieger et al 2004 ). Although it has been suggested that DCs may play a role in remodelling the cycling endometrium following menstruation, current attention is focused on their potential role in the modulation of immune responses within the pregnant uterus (Dietl et al 2006 ;Blois et al 2011 ;Leno-Durán et al 2014 ) with increasing interest into their potential interactions with uNK cells.…”

Natural killer cells in patients with hematologic malignancies, solid tumors and in recipients of hematopoietic stem cell transplantation

“…Activated NK cells regulate the following actions of DCs: cytokine-producing capacity; Th-cell polarizing ability; chemokine expression; migration, editing and maturation; and stimulatory functions. On the other hand, activated DCs are required for the execution of innate and effector functions of NK cells including NK cell differentiation [79][80][81][82][83][84]. NK cells and DCs mutually in luence each other and the bidirectional crosstalk between the 2 components of the innate immune system, that may be well coordinated, plays a pivotal role in the regulation of immune defense against viruses such as CMV, parasites such as Leishmania amazoneasis, and tumors [80,82,[85][86][87][88][89][90].…”