Exam 2- Transplantation Immunology

Question 1

what is transplantation?

Answer 1

taking cells, tissues, or organs from one individual and transferring them to the same or a different individual

Question 2

what are the two classes of alloantigens?

Answer 2

major histocompatibility (MHC) antigens: MHC molecules
minor histocompatibility antigens

Question 3

what are the two mechanisms of alloantigen recognition?

Answer 3

direct presentation and indirect presentation

Question 4

in direct presentation in alloantigen recognition, what is recognized?

Answer 4

intact donor MHC molecules

Question 5

does direct presentation or indirect presentation in alloantigen presentation evoke a stronger T cell response?

Answer 5

direct presentation

Question 6

what is the method for direct presentation in alloantigen recognition?

Answer 6

donor APCs emerge from graft and traffic to regional lymph nodes and present antigen to recipient T cells

Question 7

what is the method for indirect presentation in alloantigen recognition?

Answer 7

recipient APCs traffic to graft, collect donor antigen, and traffic back to regional lymph nodes to present antigen to recipient T cells

Question 8

what is the mixed lymphocyte reaction (MLR) used to determine?

Answer 8

if two individuals have exactly the same MHC molecules

Question 9

what is the most commonly performed type of transplantation for both dogs and cats other than blood transfusions?

Answer 9

renal allografts

Question 10

how is graft rejection classified?

Answer 10

time it takes for graft to be rejected

Question 11

what is hyperacute rejection?

Answer 11

thrombotic occlusion of graft vasculature minutes or hours after recipient blood vessels linked to graft blood vessels
previous transplantation, blood transfusion from donor, or multiple pregnancies

Question 12

what is the timeframe for acute rejection?

Answer 12

a week or so after transplantation

Question 13

what is acute rejection characterized by?

Answer 13

vascular and parenchymal injury mediated by T cells and antibodies
cytokines from Th1 cells and CTL-mediated killing of graft parenchymal cells and endothelial cells

Question 14

what is chronic rejection?

Answer 14

arterial occlusion that occurs over time as a result of intimal smooth muscle proliferation and/or fibrosis

Question 15

how is allograft rejection prevented and treated?

Answer 15

match donor and recipient MHC molecules as closely as possible
inhibit T cell activation by blocking costimulation
immunosuppressive drugs

Question 16

what is graft versus host disease?

Answer 16

alloreactive T cell and NK cells in graft attack recipient tissues

Question 17

what yields the strong response in direct presentation in alloantigen recognition?

Answer 17

combination of more recipient lymphocytes capable of responding to donor MHC molecules and the abundance of MHC molecules on the surface of the donor APCs

Question 18

where does graft rejection usually begin?

Answer 18

with graft blood vessels

Question 19

the activation of complement in acute graft rejection results in ______________________________________

Answer 19

cell lysis
thrombosis
transmural vascular necrosis

Question 20

what is the most common form of rejection?

Answer 20

chronic rejection

Question 21

is there a good side to graft versus host disease?

Answer 21

yes, in leukemia patients: low level of graft versus host disease has been shown to be beneficial because engrafted T lymphocytes kill any residual leukemia cells in the recipient