Transplantation (7)

Question 1

which two graft types are commonly rejected?

Answer 1

allograft (classmates) and xenograft (animal)

Question 2

how are foreign antigens recognized in the DIRECT pathway? how about the INDIRECT pathway?

Answer 2

direct: TCR binds MHC (on the surface of an APC) directly
indirect: traditional. APC engulfs/digests/presents portion on surface for binding
- both of them trigger a response

Question 3

mixed lymphocyte rxn is used to measure the (donor/recipient) cell proliferation?
-LOTS of proliferation: likely (acceptance/rejection) to graft?

Answer 3

recipient

-rejection

Question 4

graft rejection is more likely to occur w/ MHC class 1 or 2?

Answer 4

MHC class II (2) (recruits T helpers - doesn’t kill immediately)

Question 5

name/describe three methods of graft rejection: [HAC]

Answer 5

hyperacute: XENOgrafts present alpha-gal as their epitope
acute: vascular or parenchymal
chronic: vessel walls overgrow and choke everything downstream

Question 6

two ways to prevent graft rejection:

Answer 6

1) make it less immunogenic

2) immunosuppress the patient - preferred.

Question 7

in immunosuppression of the patient, IL-__ is compromised in BOTH cases

• how to block it’s transcription?
• how to block it’s signal transduction?

Answer 7

IL-2 = compromised. Remember - IL-2 correlated to the amt of ACTIVE proliferation

• block transcription w/ cyclosporin or tacrolimus (blocks calcineurin)
• block sig. transduction w/ rapamycin (rapamycin-coated stent)

Question 8

what is graft vs. host rxn?

-in what type of transplantation does it happen?

Answer 8

allogenic (non-self) donor’s lymphocytes react to their new host (the recipient) - usually the other way around

-allogeneic BONE MARROW transplantation

Question 9

T/F: you don’t need to worry about rejection as much in corneal transplants

Answer 9

TRUE. UNLESS neo exists on the cornea - would allow systemic immune cells to reach cornea and cause rejection rxn
-generally, very treatable w/ drops - don’t need to worry about MHC or ABO incompatibility

Question 10

what gene is found uniquely in the fetus? what’s its fxn?

what other cells is it expressed in?

Answer 10

HLA-G (histocompatibility antigen)
SUPPRESS immune fxn of the mother
RETINOBLASTOMA