L13 Transplantation & Rejection

Question 1

What is an autograft?

Answer 1

A graft of tissue from one point to another of the same individual’s body

Question 2

What is an isograft?

Answer 2

A graft of tissue between genetically identical individuals

Question 3

What is an allograft?

Answer 3

A graft of tissue between different members of the same species

Question 4

What is a xenograft?

Answer 4

A graft of tissue between members of different species

Question 5

What will determine whether or not the rejection occurs?

Answer 5

The genetic relationship between the donor and the recipient

Question 6

Which type of graft rejection is generally associated with genetic disparity between the donor and the recipient?

Answer 6

Chronic

Question 7

In which part of the genome is there the most genetic variation between humans?

Answer 7

Non-coding part

Question 8

The primary difference between individuals is in the…

Answer 8

amino acid sequence of their MHC proteins, both MHC I and II

Question 9

What happens to antigens from the donor organ (graft)?

Answer 9

They are picked up by the recipient’s dendritic cells and presented as ‘foreign antigens’ to CTLs and Th cells in lymph nodes.

Question 10

What is crucial for successful transplantation?

Answer 10

Good matching of donor (graft) and recipient MHC

Question 11

The closer the HLA typing between donor (graft) and recipient the better: True or False

Answer 11

True

Question 12

Most immunosuppressive therapies target the production or inhibition of…

Answer 12

IL-2

Question 13

Cyclosporin is derived from

Answer 13

soil fungus Tolypocladium tsukubaensis

Question 14

Tacrolimus is derived from

Answer 14

soil bacterium Streptomyces tsukubaensis

Question 15

Cyclosporin and Tacrolimus both inhibit production of __ by T cells

Answer 15

IL-2

Question 16

What is a monoclonal antibody against IL-2?

Answer 16

Basiliximab

Question 17

Mycophenolate is derived from

Answer 17

a fungus from spoiled corn, Penicillium glaucum

Question 18

Steroids are routinely used as a therapy to prevent organ rejection: True or False

Answer 18

False

Question 19

How does mycophenolate work?

Answer 19

Inhibits B & T cell proliferation by reversibly inhibiting inosine monophosphate dehydrogenase, thereby inhibiting purine biosynthesis pathway

Question 20

Who is considered high risk of organ rejection?

Answer 20

Patients with detectable anti-HLA antibodies, and those who have previously rejected a transplant

Question 21

Who are low-risk patients for organ rejection?

Answer 21

Recipients of first transplants without evidence of antibodies to HLA/MHC antigens

Question 22

IL-2 is mainly produced by what cells?

Answer 22

CD4+ Th cells

Question 23

IL-2 production leads to…

Answer 23

T cell activation and immune activation

Question 24

Cyclosporin and Tacrolimus induce __

Answer 24

immunosuppression

they also have insecticidal and anti-fungal activities

Question 25

Which transcription factor is essential for IL-2 transcription?

Answer 25

NFAT: nuclear factor of activated T cells

Question 26

What is the mechanism of action of Cyclosporin to prevent organ/graft rejection?

Answer 26

Cyclosporin blocks the activity of the phosphatase, Calcineurin. Calcineurin then cannot remove a phosphate group from NFAT (nuclear factor of activated T cells). NFAT remains inactive, IL-2 is not produced, there is no T cell activation so immunosuppression occurs.