lecture 17- transplantation immunology Flashcards
what is an example of an immunologically privileged site
cornea
define autograft
grafts exchanged from one part to another part of the same individual
define isograft
graft exchanged between different individuals of identical genetic constitutions
define allograft
graft exchanged between nonidentical members of the same species
define xenograft
graft exchange between members of different species
graft rejection is mediated by ______
lymphocytes
describe direct allorecognition
T cell recognizes unprocessed allogeneic MHC molecule on graft APCs
describe indirect allorecognition
T cell recognizes processed peptide of allogeneic MHC molecule bound to self MHC molecule on host APC
when is indirect allorecognition particularly important
during chronic rejection
define chronic rejection
when the number of donor professional APCs is too low to stimulate a direct immune response
what is the cause of hyper acute rejection
performed antidonor antibodies and complement
what is the cause of accelerated rejection
reactivation of sensitized T cells
what is the cause of acute rejection
primary activation of T cells
_____ plays an important role in triggering acute rejection
Donor DCs
what does clotting cascade generate
fibrin and fibrinopeptides
what do fibrinopeptides do
increase local vascular permeability and serve as chemoattractant for neutrophils and macrophages
what does the kinin cascade produce
bradykinin that causes vasodilation, smooth muscle contraction, increased vascular permeability
what is ABO matching NOT important for
corneal transplantation, heart valve transplantation, bone and tendon grafts
what is cross-matching used for
to test the recipient serum for preformed Abs against donor’s HLAs
what are lymphocytes from the recipient that are intact called
responder cells
what is proliferation of responder cells measured by
incorporation of tritiated thymidine
describe host-versus graft disease
when a kidney is transplanted, the recipient’s T cells attack the transplant
describe graft-versus host disease
when bone marrow is transplanted, the T cells in the transplant attack the recipients tissues
what type of T cells and cytokines are involved in humoral graft rejection
Th2 (IL-4, IL-5, and IL-10)
