Tissue-resident immunity in the female and male reproductive tract

Abstract

The conception of how the immune system is organized has been significantly challenged over the last years. It became evident that not all lymphocytes are mobile and recirculate through secondary lymphoid organs. Instead, subsets of immune cells continuously reside in tissues until being reactivated, e.g., by a recurring pathogen or other stimuli. Consequently, the concept of tissue-resident immunity has emerged, and substantial evidence is now available to support its pivotal function in maintaining tissue homeostasis, sensing challenges and providing antimicrobial protection. Surprisingly, insights on tissue-resident immunity in the barrier tissues of the female reproductive tract are sparse and only slowly emerging. The need for protection from vaginal and amniotic infections, the uniqueness of periodic tissue shedding and renewal of the endometrial barrier tissue, and the demand for a tailored decidual immune adaptation during pregnancy highlight that tissue-resident immunity may play a crucial role in distinct compartments of the female reproductive tract. This review accentuates the characteristics of tissue-resident immune cells in the vagina, endometrium, and the decidua during pregnancy and discusses their functional role in modulating the risk for infertility, pregnancy complications, infections, or cancer. We here also review data published to date on tissue-resident immunity in the male reproductive organs, which is still a largely uncharted territory.

A single-cell atlas of the aging murine ovary

“…Innate T cells are tissue resident cells thought to contribute to the maintenance of tissue homeostasis and serve as sentinel cells to detect infectious agents, neoplastic cells, or aberrant cellular damage 81 . In the female reproductive tract, innate lymphocytes display high functional diversity with both beneficial and detrimental effects 82 . However, the role of innate lymphocytes in the ovary is an unexplored subject.…”

Advances and challenges in studying the tissue‐resident T cell compartment in the human female reproductive tract

“…Pregnancy is still often referred to as an “immunosuppressed condition”, but studies examining autoimmune diseases (which can get better, worse, or stay the same during pregnancy), infections and vaccine responses do not support such a blanket statement. In the context of pregnancy, the T RM compartment in the upper FRT (reviewed in 123 and 124 ) may at first seem most relevant. However, changes in the lower FRT during pregnancy may also bear relevance for both maternal and fetal health.…”

Immunologie der Schwangerschaft: von lokalen und systemischen Protagonisten zum High-Content-Immunprofiling

“…Der Rekrutierung von Immunzellen aus der Peripherie zur Dezidua im Verlauf der Schwangerschaft steht eine Gewebsständigkeit bestimmter Immunzellen gegen-über. Diese gewebsresidenten Zellen bleiben auch nach der Geburt des Kindes im Endometrium der Mutter erhalten und vermitteln möglicherweise einen protektiven Effekt für nachfolgende Schwangerschaften [39].…”