Superficial implantation in pigs is associated with decreased numbers and redistribution of endometrial NK-cell populations.

Problem: We evaluated implantation-associated quantitative changes in endometrial and peripheral natural killer (NK)-cell populations of pigs.

Method Of Study: Natural killer cell populations were investigated in 10, 15, 20, 30 and 40 days pregnant and non-pregnant (NP) sows by flow cytometry, immunohistochemistry and morphometry.

Results: The number of endometrial CD16(+) NK cells significantly declined at attachment phase of implantation and remained relatively low over the course of implantation.

Establishment of the porcine epitheliochorial placenta is associated with endometrial T-cell recruitment.

Problem: We assessed implantation-associated quantitative changes in peripheral blood and endometrial T lymphocytes throughout epitheliochorial placenta formation.

Method Of Study: T-cell subsets were investigated in 10-, 15-, 20-, 30-, and 40-day pregnant and non-pregnant sows by flow cytometry and immunohistochemistry.

Results: Endometrial total T, T cytotoxic (Tc), and T helper (Th) cells were in peak numbers at the attachment phase of implantation and Tc cells persisted in high proportions up to placental establishment.