Immunology of pregnancy Flashcards
What are the immune challenges of the reproductive tract?
Tolerate commensal flora and Respond against infectious agents
But, Sperm must be tolerated and a Semi-allogeneic* foetus must be tolerated
Define semi-allogeneic
from the same species (allogeneic) but shares half of genetic material
How does seminal plasma provide protection against infectious agents?
Seminal plasma induces local inflammatory changes that protect against infectious agents introduced during intercourse
Which sex steroids are inflammatory?
Oestrogen is pro-inflammatory
Progesterone is anti-inflammatory
In the mouse there is an influx of ………………. at oestrus to ensure any infectious material introduced at insemination is cleared quickly
Leukocytes
Which T helper cells are inflammatory and which are anti-inflammatory?
Pro-inflammatory = Th2 dominant (CD4 Th produces IL-4, -5, -9, -13) Anti-inflammatory = Th1 dominant (CD4 Th produces IFNg, CMI)
Is pregnancy pro or anti- inflammtory?
Pregnancy – progesterone dominated
Generally favours anti-inflammatory (Th1) over pro-inflammatory immunity (Th2)
So while susceptibility to infections increases inflammatory diseases can go into remission.
Why does the mother’s immune system not reject the placenta & foetus?
The trophoblast is the first target for the mother’s immune system as it is the interface between maternal and foetal tissues Trophoblast is antigenically unusual because in general, it doesn’t express some of the main paternal antigens that are easily recognised by the maternal immune system. Examples are major histocompatibility complex antigens (MHC class I) This makes the placenta resistant to recognition and attack by maternal immune cells!
What immune cells are present in species with decidua?
Natural killer cells (NK) account for 75% of decidual leucocytes
NK cells interact with placental antigens which normally results in the production of local factors supportive of pregnancy E.g., immunosuppressive
What immune cells are present in species with endometrium?
No uterine NK cells because no decidua but other specialised immune cells are present in the uterus during pregnancy
E.g., macrophages and specialised T cells (sheep, horse)
Since placenta is less invasive, functions not as clear but may involve: Immunosuppression (Intra-uterine factors identified), Growth enhancement and Placental detachment at parturition
What immune cells are present in animals that have some degree of trophoblast invasion ?
Ruminants - Binucleate cell invasion of maternal epithelium
Equids - Chorionic girdle cells invade the endometrium and transform into binucleate endometrial cup cells
