Lecture 7 - Transplant Immunology (Bailey) Flashcards
Orthotopic
Transplanting a cell or tissue to the SAME anatomical site
Heterotopic
Transplanting a cell or tissue to a DIFFERENT anatomical site
Autologous graft
graft transplanted from one individual to the same individual
Syngeneic graft
transplanted between 2 genetically identical (or very similar) people
allogeneic graft
b/t two genetically different people
What is DIRECT alloantigen recognition?
When T-cells recognize allogeneic MHC (or allogenic MHC + self peptide)
What is an allogeneic MHC?
A non-self MHC
What is INDIRECT alloantigen recognition?
When an APC engulfs an allogenic MHC (or entire allogeneic cell), processes the MHC like a foreign protein, and presents the allogeneic MHC in the context of self MHC.
What are the 3 different types of graft rejection that can occur?
- Hyperacute rejection
- Acute rejection
- Chronic rejection
What is HYPERACUTE graft rejection?
- happens in a couple of days
- graft dies
- pre-existing alloreactive antibodies bound to the graft
What is ACUTE rejection?
- happens in a week
- cytotoxic T cells develop against graft
- B cells produce alloreactive antibodies
What is CHRONIC graft rejection?
- grafts survive for 6+ months
- alloreactive T cells produce cytokines
- macrophages activated
- inflammation
- growth factor production
- thickening of vascular smooth muscle (intimal smooth muscle)
What do hyperacute, acute, and chronic graft rejection have in common?
vascular damage leads to organ failure
Why is IL-2 important?
T-cell clonal expansion
What happens if you block CD3?
blocks activation of the T cell receptor (TCR)
What happens if you block B7?
blocks the costimulation needed for activation of T cells
What is graft versus host disease?
Graft begins to fight against the host cells
What happens when tumors down-regulate MHC I?
NK cell activation & tumor protection
What does activated NK cells produce?
IFN-(gamma)
What does IFN-(gamma) do?
lead to activation of macrophages
Macrophages are sensitive to…
cytokin microenvironment
If IFN-(gamma) is present, a macrophage will become…
an M1 Macrophage
classical activation
If any TH2-assocated cytokines (such as IL-4, IL-13, or IL-10) are present, a macrophage will become…
an M2 Macrophage
alternative activation
What do M1 macrophages do?
engulf & kill tumor cells
