Reproductive immunology

Question 1

what part of the placenta NEVER expresses MHC class II antigens?

Answer 1

outer layer ( trophoblast)

Question 2

what layer doesnt express MHC class I?

Answer 2

inner trophoblasts ( the part that is in contact with maternal blood)

Question 3

what is expressed on the villous trophoblasts that stops NK cells from destroying them ( since they are MHC I negative)?

Answer 3

HLA-G

this induces activated T cells to under apoptosis

Question 4

where is HLA-G expressed?

Answer 4

only in immune priveledged sites ( liek the thymus)

Question 5

what are the functions of HLA-G?

Answer 5

apoptosis of NK cells
induces T-reg cells ( CD4)
apoptosis of CD8 cells ( Fas-FasL path)
immuno suppreses macrophages
suppreses B cells
induces tolerance of the dendritic cells

Question 6

what is the general job of Indoleamine 2,3-dioxygenase ( IDO)?

Answer 6

causes a tryptophan deficiency–> leading to suppressing lymphocyte responses
this also causes a buildup of kineurins which help in immune homestasis

Question 7

what does the placenta secrete?

Answer 7

immunosuppressors- IL-10, TGF-Beta, prostaglandin E2

Question 8

what induces the secretion of Regeneration and tolerance factor (RTF) and progesterone induced blocking factor (PIBF)?

Answer 8

high doses of progesterone

Question 9

what is the function of RTF?

Answer 9

get cleaved and up regulate the production of IL-10 and down regulate the production of IL-2
SHIFTING TOWARD A TH2 RESPONSE

Question 10

what is the function of PIBF?

Answer 10

inhibits the release of perforin and degranulation of NK cells, INDUCTION OF TH2 RESPONSE, stimulates IL-3, 4, 10

Question 11

what is the function of RU 486 (mifipristone)?

Answer 11

blocks PIBF, casues a massive shift to TH1, leading to abortion

Question 12

what does the placenta use to prevent the activation of complement?

Answer 12

membrane cofactor protein (MCP)

Decay acelerating factor (DAF)

Question 13

what does MCP and DAF do?

Answer 13

MCP- inactivates C3b and C4b

DAF- prevents the assembly of C3bBb complex

Question 14

what is the function of the Fas and Fas ligand complex?

Answer 14

this is for the induction of apoptosis of CD8 T cells, when they attach to the FasL on the trophoblasts, the CD8 cells attach the Fas, and induces the apoptosis of the T cell

Question 15

what are teh steps in fertilization of an egg?

Answer 15

1. binding of the sperm to the surface of the zona pellucida
2. acrosome reaction
3. binding of acrosome reacted sperm to the vitelline membrane of the oocyte

Question 16

whaich sex can have anti sperm antibodies?

Answer 16

both
male- autoantigenic
female- isoantigenic

Question 17

what are the types of antisperm antibodies?

Answer 17

IgA and IgG,

Question 18

what type of IgG is the biggest problem?

Answer 18

IgG3, this leads to sperm damage

Question 19

what is the role of anti-idiotypic antibodies?

Answer 19

they bind to the anti sperm antibodies, thus making a woman with antisperm antibodies able to have children

Question 20

what can you use FA-1 Ag for?

Answer 20

this is a possible cure to antisperm antibodies casuing infertilityin males