Transplantation Flashcards
Difference between Autograft, isograft, allograft and xenograft:
Auto- one part of body to another
Isograft - two genetically identical organisms
Allograft - same species
xenograft - different species
Explain 1st set and 2nd set rejections:
Graft rejections induce memory T cells which can then be transferred
Eg if you give mouse A skin X and it rejects it
and then transfer the first mouse’s T cells to another mouse A
then give the second mouse X skin - it will reject it faster and stronger - second set
What do you call non self MHC?
Allo MHC
What are the two paths of recognition of graft Ags by alloreactive T cells:
Direct and Indirect
Describe the direct path of reacting against donor cells:
T cell recognises allo MHC + non tolerant self peptides on Donor cell - kills it
Describe the indirect path of reacting against donor cells:
APC takes up allo MHC and allo peptides from donor, processes it, puts it up on its own MHC II - shows it to Tcell- self MHC and allo peptides
How do we avoid transferring immune cells in with the graft?
Wash out the organ
When does GVHD occur? how?
Bone marrow transplants - recipient T cells recognise own cells as foreign an start attacking them. Recipient is immunosuppressed so can’t reject graft.
Live vs dead donor :
Live donor better
Which transplants dont need to be matched?
cornea (not vascularised)
heart valve
4 types of rejection reactions and timeline:
Hyperacute (min/hours)
Accelerated (days)
acute (days /weeks)
Chronic (months / years)
Cause of hyperacute:
The recipient had anti donor antibodies and complements - medical error
Cause of accelerated
Reactivation of sensitive T cells
Cause of acute:
primary activity of T cells
Chronic cause:
Unknown, Abs, immune complexes, slow cellular reaction, recurrence of disease
