Transplantation and Immunosuppressive Drugs Flashcards Preview

𝓘𝓂𝓂𝓊𝓃𝑜𝓁𝑜𝑔𝓎 > Transplantation and Immunosuppressive Drugs > Flashcards

Flashcards in Transplantation and Immunosuppressive Drugs Deck (56)
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1

What is the definition of transplantation?

➝ The introduction of biological material (organs, tissues, cells) into an organism

2

What is an autologous transplant?

➝ transplantation of tissue from one part of the organism to another part of the same organism

3

What is an example of an autologous transplant?

➝ Skin graft

4

What is a syngeneic transplant?

➝ donor material transplanted into the recipient when the donor and recipient are genetically identical

5

What is an allogenic transplant?

➝ Donors and recipients are from the same species but genetically different

6

What is a xenogenic transplant?

➝ donor and recipient are different species

7

What are immune responses to transplant caused by?

➝ genetic differences between the donor and recipient

8

What are human MHC proteins called?

➝ human leukocyte antigen

9

On what chromosome is HLA found?

➝ chromosome 6

10

How many MHC Class I alleles are there?

➝ 3
➝ A, B, C

11

How many MHC Class II alleles are there and what structures do they form?

➝ 3
➝ heterodimers of two proteins

12

Which cells in the body express both MHC class I and II?

➝ White blood cells

13

What are the MHC Class II alleles?

➝ DRA
➝ DRB
➝ DPA
➝ DPB
➝ DQA
➝ DQB

14

What is needed to define epitopes on HLA?

➝ next generation sequencing

15

What do T cells recognise?

➝ short peptide fragments that are presented to them by MHC proteins

16

What can professional APCs do with external proteins?

➝ internalise them and cross present them on the MHC class I pathway

17

What does MHC class II bind?

➝ Fragments of proteins which have been taken up by endocytosis

18

What does MHC Class I bind?

➝ Fragments of intracellular proteins

19

What is the function of CLIP?

➝ Maintains the shape of the HLA until the peptides are ready to bind

20

Describe indirect allo-recognition?

➝ The recipient cell has self HLA on its cell if the cell expresses the self peptide as normal cells do there is no immune response
➝ the TCR will be quiescent
➝ When self HLA presents a peptide (eg influenza peptide) an immune response will occur against the influenza
➝ if the recipient has a transplantation and the self HLA can present a peptide from the donor HLA molecule there is indirect allo-recognition

21

What is indirect allo-recognition?

➝ TCR of recipient detecting non-self peptide on self HLA

22

Describe direct allo-recognition?

➝ A recipient has transplanted tissue which contain donor immune cells
➝ If they have been perfectly matched the donor HLA is the same as the recipient HLA and there is no reaction
➝ when there is an unmatched donor there is direct allo-recognition
➝ the TCR from the recipients T cells will detect the MHC
➝ even if the peptide isn't recognised as foreign (because it is from a conserved region) the unmatched HLA activates the T cells

23

What is direct allo-recognition?

➝ TCR of the recipient reacting to donor HLA molecules

24

How many MHC loci are usually matched?

➝ 4/6 MHC class II loci

25

Why are live donors better than dead donors?

➝ Recipients will have a history of disease which results in a degree of inflammation
➝ organs from deceased donors are likely to be inflamed due to ischemia

26

What are the three types of graft rejection?

➝ Hyperacute rejection
➝ Acute rejection
➝ Chronic rejection

27

When does hyperacute rejection occur?

➝ within a few hours of transplant

28

What organs does hyperacute rejection usually occur with?

➝ highly vascularised organs

29

How does hyperacute rejection occur and what is needed?

➝ requires pre-existing antibodies usually to ABO blood group antigens or MHC I proteins
➝ ABO antigens are expressed on endothelial cells of blood vessels

30

What are the three ways antibodies to MHC can arise?

➝ Pregnancy
➝blood transfusion
➝ previous transplant