Transplant Immunology Flashcards
What is an orthotopic transplant?
Transplanting to the same anatomical spot
What is an allergenic graft?
Graft between two genetically different individuals
What does it mean to be alloreactive?
Immune cells react to an allogenic graft
What type of MHC results in CD4+ T cells?
MHCII
What type of MHC results in CD8+ T cells?
MHCI
What is the positive selection of T cells?
Low-affinity to self peptide and MHC II
What results in negative selection of T cells?
High affinity for peptide-MHC or no affinity = cell death
T/F: In a typical immune response, T cells recognize a non-self peptide and a self MHC molecule.
TRUE
What is direct alloantigen recognition?
T cells recognize either non-self MHC or a non-self MHC + peptide complex
What is indirect alloantigen recognition?
APC engulfs foreign MHC -> processes it -> presents in with self-MHC -> T cell recognizes self from foreign
What are the key events in hyperacute rejection?
- Pre-existing antibodies lead to activation of compliment cascade
- Inflammation and reactive endothelium
*Minutes to hours
What is acute rejection?
Alloreactive T cells become activated and lead to the immune system attacking the graft
*About a week
What is chronic graft rejection?
T cells produce cytokines lead to parenchyma macrophages -> growth factors lead to intimate smooth muscle formation
What do anti-rejection medicines like Repamycin, and Anti-IL-2 receptor antibodies target in the body?
T cell mechanisms
What type of transplants result in graft vs host disease?
Bone marrow
