Transplant Immuno Flashcards
T/F. The primary reason for morbidity and mortality involves the immune response.
True.
What reasons lead to morbidity and mortality?
immune response to the graft = rejection
infection due to immunosuppression
graft attacks the host (graft vs host disease/bone marrow transplant)
Define graft.
Cells or tissues that is being transplanted
Orthotopic means transplanting a cell or tissue to the ___ (same/different) anatomical site. Heterotopic means transplanting cells or tissue to the ___ (same/different) site.
same; different
What is the process of the transfer of circulating cells from one individual to another?
transfusion
What type of graft is transplanted from one individual to the same individual?
Autologous graft
A ___ graft is transplanted between two genetically identical (or very similar) individuals.
syngeneic graft
Define allogeneic graft.
graft between two genetically different individuals
Explain the Sir Peter Medawar experiment?
skin graft from one mouse to another. 7-10 days later inflammation at graft site lead to rejection.
What is the second set rejection?
Mice sensitized with rejected skin graft prior to new graft showed rejection after 3 days. This showed immunological memory
What happened after mice B were given lymphocytes from another mouse B that has already rejected a graft from mouse A?
mice B will reject graft A after 3 days. This showed that lymphocytes mediate rejection and memory
How are T cells acitvated?
T cells recognize antigen that is present to them in the context of MHC.
CD4+ T cells require antigen + MHC ___ to be activated. CD8+ T cells require antigen + MHC ___ to be activated. What else is also needed?
II; I; co-stimulation
How does the body prevent the development of autoreactive T cells? When does this work?
Immature thymocytes with low avidity binding to self peptide and MHC allow T cells to mature into antigen specific cells. However, high avidity binding to self peptide and MHC leads to apoptosis.
This only works for self peptide and self MHC.
What percentage of T cells can recognize self peptide and non-self MHC?
2%
Explain allorecognition.
The self MHC-restricted T cell recognizes the allogeneic MHC molecule whose structure resembles a self MHC-foreign peptide complex.
T/F. Most of the peptides are likely to be self peptides that are the same in the donor and the recipient, but the donor peptides are displayed by allogeneic MHC molecules and therefore appear different from self peptide-self MHC complexes.
True.
What is it called when T cells recognize allogeneic MHC (or allogeneic MHC + self peptide) directly?
Direct alloantigen recognition
How does indirect alloantigen recognition occur?
- recipient APC can engulf allogeneic MHC
2. recipient APC can process the MHC