Transplantation Flashcards
Which MHC class is identified by Ab? Which is identified by mixed lymphocyte reaction?
Ab- class I, mixed lymphocyte reaction- class II
Why do we have such great polymorphism in MHC?
If a random disease comes along the diversity in MHC means that some person in the population will likely be able to mount an immune response against it. It also helps prevent accidental transplant such as a tumor passing between two people.
What is Rho gam?
Ab against Rh+, prevents immune response by sequestering Ag
What are various ways you can have antibodies to HLA/IgG Ab?
previous transplant, blood transfusions (formed elements immunize against HLA), when woman gives birth
What does panel reactive antibody test for?
detects presence of antibodies to HLA
What does alloantibody mean?
antibody against the same species, but different HLA type (non-self MHC)
How do corticosteroids help in transplants?
interfere with transcription factor needed to turn on genes for T cells to become activated, reduce inflammation, immunosuppressants
What are two examples of corticosteroids?
prednisone, prednisolone
Why are cytotoxic drugs (purine analogs) used in transplant therapy?
interfere with DNA synthesis and rapid cell proliferation needed for immune response
How do FK506 and cyclosporine work as transplant rejection therapies?
natural products isolated from microbial cultures that inhibit signaling pathways used by T cells to turn on their genes for activation (IL-2 secretion)
Why doesn’t anti-lymphocyte Ig cause serum sickness?
it knocks out T cells so you can’t mount immune response against it or create Ab since you don’t have T cell help for B cell activation
What can monoclonal Abs target to treat transplant patients?
CD3 molecule on T cell surface, IL-2 receptors to only inhibit activated T cells
What is CTLA-4-Ig?
ligand for B7 combined with Fc region of IgG, blocks costimulation of T cells so they are anergic
-as effective as cyclosporine but less toxic
The likelihood of what increases with class II mismatch?
GVHD, more varied MHC class II on T cells in donor tissue will elicit greater response
