Immunological Aspects of Reproduction

Question 1

Name three challenges to the uterus which may provoke an immune response?

Answer 1

Allowing sperm to survive, bacteria introduced during intercourse, fetus

Question 2

What specialised immune features have the epithelial cells lining the reproductive tract developed?

Answer 2

Receptors recognise pathogens & produce natural anti-microbial peptides

Question 3

What is the function of seminal plasma?

Answer 3

Induces local inflammatory changes that protect against infectious agents introduced during intercourse

Question 4

What are the inflammatory effects of oestrogen and progesterone?

Answer 4

Oestrogen is pro-inflammatory, progesterone is anti-inflammatory

Question 5

Define the fetoplacental allograft?

Answer 5

The conceptus must be regarded as an intra-uterine foreign graft, owing to the inheritance of paternal genes not shared by the mother, fetus & trophoblast are both considered grafts

Question 6

What determines the number of maternal layers of the placenta?

Answer 6

How invasive the trophoblast cells are

Question 7

Name two mechanisms which are thought to be involved in survival of the fetal allograft?

Answer 7

Deliberate exposure (ruminants), lack of MHC, local immune suppression

Question 8

What immune cells are present in the uterus?

Answer 8

With decidua – NK cells

With endometrium – macrophages, specialised T cells (placenta is less invasive)

Question 9

Which domestic species do exhibit some trophoblast invasion?

Answer 9

Ruminant – binucleate cell invasion of maternal epithelium

Equids – chorionic girdle cells invade the endometrium and transform into binucleate endometrial cup cells

Question 10

Does the equine trophoblast express MHC class I?

Answer 10

Chorionic girdle yes, endometrial cup no

Question 11

Is there an immune response to pregnancy?

Answer 11

Yes, antibodies, cell mediated

Question 12

What is the nature of the immune response?

Answer 12

NK cells found at the base of the cup (these cells attack and destroy the cup around 120 days)

Question 13

Does the trophoblast influence its immunological environment?

Answer 13

Yes, factors secreted throughout the stages of pregnancy that suppress mothers immune system

Question 14

Does the pregnant endometrium regulate local immune responses?

Answer 14

Yes

Question 15

Is the immune response the same in the peripheral and local environment?

Answer 15

Don’t know, evidence suggests split tolerance, i.e. suppressed locally

Question 16

Is MHC class I expressed on equine trophoblast?

Answer 16

Chorionic girdle cells, endometrial cup cells, allantochorion

Question 17

Name three potential mechanisms to explain the survival of the trophoblast?

Answer 17

Immunosuppressive factors are secreted by trophoblast/endometrium, modulation of local immune response – pregnancy induces a Th2 state