17.7 Immunology: Transplantation Flashcards
What is the difference between an: Allograft Isograft Autograft Xenograft
Allo: between different members of same spieces
Iso: between monozygotic twins
Auto: self
Xeno: interspecies
Why does ABO incompatibility result?
Surface carbohydrates
What happens if you give a second skin graft from original donor to same recipient in mice?
Graft show accelerated rejection
What cell is responsible for rejection?
T-cell
What are histocompatibility antigens encoded by?
MHC
Where are MHC HLA genes encoded?
Chromosome 6
Explain the differences between MHC I and II
I: universally expressed, cytoplasm derived proteins, CD8+
II: APC (and inducible), extracellular derived proteins, CD4+ T cells
What is graft survivial of solid organ transplants directly related to?
HLA matching (A, B, DR)
What are the differences between matching for Renal and Lung Tx?
Renal: HLA matching
Lung: HLA mismatches (take what we can get)
What are the three time courses for rejection reactions and why do they occur?
Hyperacute (preformed antibodies/C’)-mins/hrs
Acute (primary activation of T cells)-days/weeks
Chronic: Unclear, AB?Immune complexes?-months/yrs
How does AMR occur?
Preformed antibodies (e.g. ABO, MHC)
Or previous transfusion, pregnancy, transplant
What happens in chronic allograft rejection?
Intimal fibrosis–>loss of tubules
What are three ways we prevent allograft rejection?
Matching ABO antigens
Matching MHC alleles
Immunosuppressive drugs
What does T cell activation stimulate?
Immunological cascade
What are 3 categories of immunosuppressive drugs?
Calcineurin inhibitors
Anti-inflammatory (steroids)
Anti-proliferative
