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

Abstract

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. The number of gammadelta T lymphocytes was relatively small and implantation-independent. In situ, T cells increased in number with the advancement of implantation and formed T-cell clusters with implantation phase-dependent location. Percentages of peripheral blood T cells were not significantly changed throughout the implantation.

Conclusion: Superficial and adeciduate implantation of pigs has a profound effect on the number of total T, Tc, and Th cells and pattern of distribution of endometrial T cells in situ.