Uterine natural killer cells

Rat uterine natural killer cell morphology also differs from the mouse due to the common occurrence of myelin within the granules.

In all species, as active cells, they have numerous prominent organelles including mitochondria, well-developed golgi apparatus, free ribosomes and rough endoplasmic reticulum.

[3] Notably, mouse models suggest that they lack CD16 and L-selectin, proteins that are prominent on pNKs (peripheral NK cells).

In mice, uterine natural killer cells were also found to produce growth-promoting factors which are important in early development before the placenta is fully formed.

These cells are attracted to the uterus during pregnancy independent of chemokine receptors CCR-2 and CCR-5[5] in spite of these being important in recruitment of other inflammatory responses, and the exact method of their homing is yet to be understood.

[7] Uterine natural killer cells secrete trophoblast invasion promoting cytokines (IL-8 and IP-10) and various angiogenic factors required for remodelling maternal spinal arteries in order to support sufficient perfusion of the placenta in later pregnancy.