Immunology Week 3 Flashcards
Isograft vs. allograft vs. xenograft
Iso is between identical twins/inbred mice. Allo is between individuals of the same species. Xeno is between species
What is the main target of donor reactive immune response after transplantation
Polymorphic HLA/MHC molecules are major antigen
What destroys a transplanted organ?
alloantibodies and effector T cells after both donor and recipient APCs go to LNs
When can alloreactive antibodies develop?
Upon exposure to alloantigens in pregnancy, blood transfusion, transplant, or cross reactivity
Direct allorecognition
Donor APC presents donor self peptide, but is activated because of DAMPs so they go to nearest lymph node – recipient anti-donor T cells are activated, proliferate, attack graft. This is more potent than indirect (which is closer to nl immune rxn).
Indirect allorecognition
is exact same thing as direct, but with recipient APC
What is a DAMP
Danger-Associated-Molecular-Patterns. Can initiate and perpetuate immune response in the noninfectious inflammatory response. Released from ischemic tissues
What does calcineurian do?
Helps activate IL-2 gene, which stimulates T cell differentiation and proliferation
What does CD28 bind to?
B7, costimulation
DTH
delayed type hypersensitivity, type IV. Macrophage activation, chemoattraction, TNF released. May account for acute cellular rejection.
What is the FAS ligand?
Part of the tumor necrosis factor TNF family. Induces apoptosis when bound to receptor. both TMs
How do you diagnose acute cellular rejection?
Decreased kidney fxn (rise in serum creatinine) - do renal biopsy. Mononuclear cells, T-cells, and macrophages predominate, but antibodies also contribute. Thought to be due to the direct pathway.
Immunosuppression
Primarily targets T, not B cells. Nonspecific. Chronic rejection can lead to kidney fibrosis.
How do corticosteroids help with transplant immunity?
Block IL2 transcription
Graft vs. Host disease
Bone marrow transplant - donor bone marrow lymphocytes can react to host/recipient cells. Causes tissue damage.