Immunology of pregnancy

Question 1

Describe the morphology of the synctiotrophoclast in the placenta

Answer 1

single cell layers which multiple nuclei, prevents mom and baby’s blood from mixing

Question 2

How do the trophoblasts of the placenta protect the fetus?

Answer 2

1. do not express classical MHC molecules –> prevent T cell activation
2. express non-classical MHC molecules –> prevent NK killing
3. inactive FAS –> non Fas-induced apoptosis
4. production of hormones –> increases Th2 and reduces Th1 type response
5. production of soluble TNFalpha, IL-6 and IL-2 Rs –> blocks activity of these cytokines, reducing Th1 type immune responses

Question 3

When is a baby colonized with bacteria, what hypothesis does this support?

Answer 3

colonized during birth –> supports sterile womb hypthesis

Question 4

What infections are associated with congenital anomalies?

Answer 4

Toxoplasmosis
Other - syphilllus, VZV
Rubella
Cytomeglovirus
Herpes infection

Question 5

Is the placental barrier effective against pathogens

Answer 5

Somwhat effective depending on the pathogen. E.g. infection with HCMV = 40% transmisson to baby –> suggests there is a barrier

Question 6

What are some features of microchimerism?

Answer 6

• normal
• bi-directional trafficking of fetal and maternal cells
• low levels
• cells persist for a lifetime
• highly conserved

Question 7

What are the positive effects of microchimerism on the mom and offspring?

Answer 7

maternal:
- existing Tregs may enhance fetal protection in next pregnancy
- pluripotent fetal microchimeric cells may differentiate into and replace diseased cells in maternal tissues

offspring:
- protect against fetal loss in the next gen pregnancies under conditions that interrupt fetal tolerance mechs
- more Tregs may dampen inflammation from microbial colonization, training the neonatal immune response
- reduce rejection of transplants

Question 8

What are the negative effects of microchimerism?

Answer 8

can lead to the onset of many diseases

Question 9

Describe three more protective physiology mechanisms of the placenta

Answer 9

1. ST expressed FASL –> kill activated maternal immune cells
2. IDO depleted tryptophan –> inhibits T cell proliferation
3. decidual IL-10 and TGF-beta inhibit T cells responses

Question 10

Describe the Th1 and Th2 balance in the decidua

Answer 10

Th2 predominate, especially compared to non-pregnant women

Question 11

What are some pros and cons of more Th2 type responses?

Answer 11

pro: clear gut worms more efficiently
con: fail to resist some other major infections

Question 12

How does MHC matches affect pregnancy?

Answer 12

match –> increase chance of pregnancy loss in humans

Question 13

What mediates tolerance to paternal Ags found on fetuses?

Answer 13

Tregs

Question 14

How can exposure to sperm affect human pregnancy outcomes?

Answer 14

women with greater and longer exposure to seminal plasma from the same partner are at a smaller risk for preclampsia

Question 15

What three pregnancy-related conditions are caused by low Treg pops?

Answer 15

• spontaneous abortions
• infertility
• preeclampsia