Adaptive Immune Responses During Pregnancy

Abstract

It has long been believed that there is no immune interaction between mother and conceptus during pregnancy. This concept changed after evidence was provided that the maternal immune system is aware of the semiallogeneic conceptus and develops strategies to tolerate it. Since then, finely regulated mechanisms of active tolerance toward the fetus have been described. This Special Issue of the American Journal of Reproductive Immunology deals with these mechanisms. It begins with the description of minor histocompatibility antigens in the placenta; it further goes through adaptive immune responses toward paternal fetal antigens, mostly concentrating on regulatory T cells and molecules modulating the Th1/Th2 balance. The participation of antibody‐producing B cells in normal and pathological pregnancies is also discussed. This introductory chapter resumes the concepts presented throughout the Issue and discusses the clinical applications raised from these concepts.

THE ROLE OF THE DIFFERENT SUBPOPULATIONS OF CD4⁺Т LYMPHOCYTES DURING PREGNANCY

“…Treg cells include CD4 + T lymphocytes, expressing CD25 high and able to have suppressive action on autoreactive T lymphocytes [140]. It should be noted that CD25 is not a molecule, necessary to realize Treg suppressive properties [109].…”

“…Galectin-1 induces effector T cell apoptosis [143]. Reduced galectin-1 expression may underlie Тh1 and Тh17 activation [140]. Glycodelin A (GdA) is abundantly expressed by decidua stroma and is bound with almost all T lymphocytes.…”

“…Vasoactive intestinal peptide (VIP), which secretion peak in the zone of the uteroplacental bed occurs during early placentation period, increases Treg concentration in the decidua, stimulates LIF secretion by the trophoblast [34], and facilitates maintenance of tolerogenic phenotype of decidua macrophages [140]. VIP also reduces secretion of IL-6, MCP-1 and stimulates secretion of IL-10 by peripheral blood mononuclears in pregnant women [34], which can promote tolerance formation in the mother-fetus system.…”

L’implantation embryonnaire

“…En outre, l'IL18 produite en excès favorise un déséquilibre pro-Th1 susceptible d'entraîner une activation immunitaire délétère, notamment via les cellules uNK qui se transforment en LAK (lymphokine-activated killer cell), mais égale-ment via les cellules dendritiques et les cellules Th17. Un déséquilibre en faveur d'une dominance Th1/Th17 est délétère pour la grossesse et peut s'accompagner de prééclampsie, d'accouchement prématuré ou d'avortement spontané [27][28][29][30][31].…”

Phenotypic and functional analysis of bovine peripheral blood dendritic cells before parturition by a novel purification method

“…In order to prevent fetal rejection caused by the recognition of paternal antigens, the maternal immune system has to be mobilized toward tolerance (Zenclussen, 2013). T helper (Th) cells play a central role in immune responses.…”