transplant immunology Flashcards
Graft transplanted from one individual to the same individual
autologous graft
Graft transplanted between two genetically identical (or very similar) individuals
syngenetic graft
Graft between two genetically different individuals
allogenetic graft
transplanting a cell or tissue to the same anatomical site
orthotopic
transplanting a cell or tissue to a different anatomical site
heterotopic
transfer of circulating cells from one individual to another
transfusion
____ immune cells react to allogeneic grafts
alloreactive
rejection of a graft is due to mismatch in ____ molecule; if it does not match, T cells will recognize graft as foreign
MHC
CD4+ T cells require ____ to become activated
antigen + MHC II
CD8+ T cells require _____ to become activated
antigen + MHC I
T cell binds to self MHC and foreign peptide with ____ affinity
high
MHC II + peptide activates CD4+ T cells and T cells produce ____ to help propagate the immune response
cytokines
self MHC molecule presents foreign peptide to T cell selected to recognize ____ weakly, but may recognize ____ complexes well
self MHC; self-MHC/ foreign peptide complexes
two examples of direct alloantigen recognition
- T cell recognizes allogeneic MHC molecule whose structure resembles self MHC+foreign peptide complex
- T cell recognizes structure formed by both allogeneic MHC molecule and bound peptide (self peptide)
If the allogeneic MHC+self peptide
is structurally similar to self MHC and foreign peptide, it will result in _____
T cell activation
When T cells recognize allogeneic MHC (or allogeneic MHC+self peptide) directly it is called ______
direct alloantigen recognition
presentation of processed peptide of allogeneic MHC molecule bound to self MHC molecule
indirect alloantigen recognition
indirect alloantigen recognition is an example of ____ or ____
cross presentation; cross priming
how do allogeneic T cells lead to graft rejection?
- hyperacute rejection
- acute rejection
- chronic rejection
hyperacute rejection is characterized by ____ and eventual ____of the graft blood vessel that begins within ____ of the transplant
thrombosis formation; occlusion; minutes to hours
results of hyperacute rejection
complement activation, endothelial damage, inflammation and thrombosis
in acute rejection, ____ become activated after about a week and produce cytokines
alloreactive T cells
results of acute rejection
parenchymal cell damage
interstitial inflammation
endothelialitis
grafts that survive for 6 months or more can eventually develop ____ due to _____
blood vessel thickening; intimal smooth muscle formation
results of chronic graft rejection
chronic DTH reaction in vessel wall
intimal smooth muscle cell proliferation
vessel occlusion
cells from the common myeloid progenitor
erythrocytes (RBCs), platelets, basophils, eosinophils, neutrophils, monocytes/macrophages
cells from common lymphoid progenitor
B lymphocytes, T lymphocytes, NK cells
While same immune reactions/rejection can occur with bone marrow transplant, there is also the risk of the graft attacking the host, which is called:
graft vs host disease
tumor antigens are recognized by _____
tumor-specific CD8+ T cells
types of tumor antigens recognized by T cells
- mutated forms of normal self proteins
- product of oncogene or mutated tumor suppressor gene
- overexpressed or aberrantly expressed self protein
- products of oncogenic virus
Some cancers can down-regulate the expression of MHCI. Why is this important to the immune system?
NK cell becomes activated and can kill infected cell
activated NK cells cal produce ____
IFN-gamma
the production of IFN-gamma is important because?
IFN-gamma activates macrophages and allows them to kill phagocytosed tumor cells
function of tumor macrophages depends upon the ____
cytokine microenvironment
____ leads to M1 (or classical) macrophage activation
IFN-gamma
_____ leads to M2 (or alternative) macrophage activation
IL-4, IL-13, IL-10
M1 macrophages can suppress tumors/kill tumor cells through _____
bactericidal activity
immunostimulation
inflammatory cytokines
M2 macrophages can enhance tumors through _____
scavenging
tissue repair
matrix remodeling
angiogenesis
The principal mechanism of tumor immunity is killing of tumor cells by ____
CD8+ cytotoxic T lymphocytes
experimental evidence suggests that the CD8+ CTL’s are most effective against _____
DNA virus-induced tumors
____ may be necessary for CTL activation
cross-priming
role of CD4+ T cells in CTL differentiation
- help to activate CD8+ T cells- produce cytokines that stimulate CTL differentiation
- produce Th1 cytokines that lead to classical (M1) macrophage activation
People with _____ are at an increased risk of developing cancer
chronic inflammatory diseases
