Endocrine Abstracts

Mammalian pregnancy is characterized by tremendous changes and adaptations in the endocrine as well as in the immune system. Early in pregnancy, levels of female sex hormones, progesterone (P₄) and estradiol (E₂) produced by the corpora lutea (CL) significantly rise, promoting huge modifications of the uterine epithelium ensuring embryo implantation. Once the embryo is implanted, trophoblast cells produce and release increasing levels of human chorionic gonadotropin (hCG), which among other functions stimulates the CLs to continue producing progesterone. Simultaneously, the maternal immune system undergoes several adaptations; e.g., expansion of regulatory B and T cells, tending to ‘accept’ the presence of the semi-allogeneic fetus expressing foreign antigens.

These modifications and adaptations of the endocrine and immune system are not independent of each other but highly coordinated. Indeed, alongside with the above-mentioned functions, female sex hormones actively participate in the process of shaping immune cells toward a transient state of tolerance necessary for the maintenance of pregnancy.

B-lymphocytes are pleiotropic cells belonging to the adaptive arm of the immune system. Besides their well-known function as antibody-producing cells, B-lymphocytes can produce a broad variety of cytokines as well as present antigens to T cells, thus they have a central role in regulating an immune response.

In this talk I will present and discuss different mechanisms of how female sex hormones influence and coordinate B cell functionality in the context of pregnancy.

Disclosure: This study was supported by grants from the Fritz Thyssen Foundation to FJ (Az. 10.12.2.155) and intramural founding from Medial Faculty, Greifswald University.