Organ Graft Rejection - TOKA Flashcards
What graft will cause the strongest immune rxn to reject the graft?
Xenograft
What is the most frequent type of graft?
Allograft
Which organ grafts do not trigger an IR?
Autograft and Isograft
What is an allograft?
Transplant between different members of the same species
Ex: Pug graft to a golden retriever
** can cause IR and rejection of graft
What is an autograft?
When tissue is moved to a dif part of the animals own body
Ex: skin to cover a burn
What is an isograft?
Tranplant between 2 genetically identical individuals
A pig heart was put into a human. What type of graft is this?
Xenograft
What is the organ graft that is transplanted between animals of different species?
Xenograft
Ex: baboon heart to human infant
________ rejection occurs within 48 hours after grafting
Hyperacute
________ rejection occurs UP TO 7 days after grafting
Accelerated rejection
________ rejection occurs after 7 days after grafting
Acute
________ rejection develops months after grafting
Chronic
If a graft is repeated from the same donor _______________ + __________ will become involved to rapidly reject the graft
Ab + Complement
Acute rejection of a graft becomes infiltrated by __________
Cytotoxic T cells
Allografted organs are a major source of foreign molecules which include __________
Blood group antigens + MHC molecules (I + II)
Which grafts are never rejected?
Between genetically identical individuals/ same individual
Isograft or Autograft
How can you prevent an allograft rejection?
Minimally suppress the immune system
- Inhibit T cell signalling pathways (Cyclosporine/ Tacrolimus)
- Antimetabolites
- Block Co stim (CTLA4-Ig)
- Corticosteroids (anti-inflamm)
- Target alloantibodies + alloreactive Ab
What are metabolic toxins that kill proliferating T cells?
Antimetabolites
*** used to suppress IR + prevent graft rejection
What type of graft rejection causes arterial occlusion due to proliferation of smooth muscle cells?
Chronic rejection
** SM thickens and makes lumen smaller = occlusion
What are signs of chronic rejection?
GRADUAL rise in creatine and urea
Proteinuria
Hematuria
A rapid rise in creatinine would indicate a _________ graft rejection
Acute
What is the direct pathway of graft rejection?
T cells recognize unprocessed peptides of allogenic MHC molecules on APC and trigger response
What is the indirect pathway of graft rejection?
Presentation of processed peptides of allogenic MHC molecules on self MHC molecule
** Cytotoxic CD8+ T cells and Ab enter graft and destroy it
What can bone marrow allografts be used for?
Helps treat some tumors
