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Flashcards in 13 MHC and transplantation Deck (10)
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1
Q

How many MHC molecules are there on the average mammalian cell?

A

50-100,000

2
Q

Where on the chromosome is the HLA complex?

A

6p21.3

3
Q

The HLA complex has three regions, which antigens does each encode?

A

1: HLA-A/ B/ C
2: HLA-DR/ DQ/ DP
3: HSP70, TNF, C4A, C4B, C2, BF, CYP21

4
Q

The two classes of antigens are found on different cells, which is where?

A

1: all nucleated cells
2: B lymphocytes (may be induced on T lymphocytes)

5
Q

The two classes of antigens have different structures - distinguish between them.

A

1: 45kd heavy chain and B2 microblobulin
2: 31kd a chain and 26kd B chain

6
Q

How is the HLA complex inherited?

A

En-bloc from each parental chromosome. Codominant expression - all inherited antigens are displayed (HLA phenotype).

7
Q

What is the difference between direct and indirect MHC recognition?

A

Direct: white blood cells from donor present directly to recipient T cells.
Indirect: foreign proteins are broken down and presented to T cells by MHCII of self APC’s

8
Q

What is sensitisation? Name three examples.

A

Any event which elicits an HLA directed immune response.

Pregnancy, blood transfusion, transplantation.

9
Q

How are the chances of an organ transplant determined by immunologically?

A

Blood group.
HLA type.
Sensitisation.

10
Q

What is hyper-acute rejection of an organ transplant?

A

Activation of the clotting cascade and complement system leading to loss of vascular integrity and DIC. Results in death.

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