Establishment of the Porcine Epitheliochorial Placenta Is Associated with Endometrial T-Cell Recruitment


Tanya Dimova, Department of Immunobiology of Reproduction, Institute of Biology and Immunology of Reproduction, Acad.K.Bratanov, Bulgarian Academy of Sciences, 73 Tzarigradsko Shosse, 1113 Sofia, Bulgaria. E-mail:



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.


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 γδ 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.


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.