TCR and MHC

Question 1

What are the two T cell sub-populations?

Answer 1

CD4+ and CD8+

Question 2

CD

Answer 2

Cluster of differentiation, important for signalling and have functions.

Question 3

What type of T cell are CD4+

Answer 3

Helper T cells

Question 4

What type of T cell are CD8+ cells

Answer 4

Cytotoxic T lymphocytes CTL

Question 5

What do T CD4+ and CD8+ cells both have?

Answer 5

TCRs and CD3+

Question 6

How does the APC cell present antigen?

Answer 6

On MHC molecules on its surface post processing, presenting the peptide epitope.

Question 7

How is the T cell able to interact with APC?

Answer 7

The T cell has a complemetary recognition site on the TCR allowing it to bind to the peptide epitope on the MHC on the APC.

Question 8

What is the stucture of a TCR?

Answer 8

2 variable domains alpha and beta.
2 constant domains alpha and beta.

Question 9

What makes up the antigen recognition site?

Answer 9

The two variable domains on the TCR.

Question 10

What makes up the TCR “complex”.

Answer 10

TCR and CD3

Question 11

What is the function of CD3 in the TCR complex

Answer 11

Signalling

Question 12

CDR

Answer 12

Complementary determining regions are loops corresponding to MHC/peptide binding sites.

Question 13

How many loops each from the beta and alpha variable domains interact with the antigen?

Answer 13

Three

Question 14

What class of MHC is recognised by CD4+ T cells?

Answer 14

MHC Class II

Question 15

What class of MHC is recognised by the CD8+ T cells?

Answer 15

MHC Class I

Question 16

Function of CD8+ CTL

Answer 16

Kill abnormal cells

Question 17

Function of CD4+ T cells

Answer 17

Coordinate immune response

Question 18

On what type of cell are MHC Class I molecules expressed on?

Answer 18

All nucleated cells

Question 19

On what type of cell are MHC Class II molecules expressed on?

Answer 19

APCs, B cells, DCs and macrophages

Question 20

What type of antigen do MHC Class I molecules present?

Answer 20

Intracellular/endogenous antigens from within the APC.

Question 21

What type of antigen do MHC Class II molecules present?

Answer 21

Extracellular/exogenous antigens taken up by endocytosis from outside the cell.

Question 22

What is the MHC Class I molecule strucure?

Answer 22

Alpha heavy chain (3 domains), 2 of which are the peptide binding site.
Beta-2-microglobulin

Question 23

What is the MHC Class II molecule strucure?

Answer 23

Beta and alpha chains.
Domain from each of the chain makes up a peptide binding sites.

Question 24

What codes for MHC?

Answer 24

Complex of genes encoding proteins involved in immunity!

Question 25

What does Class I region code for?

Answer 25

MHC Class I heavy chains HLA-A to C.

Question 26

What does Class II region code for?

Answer 26

MHC Class II molecules HLA-DR, -DP and -DQ.

Question 27

What does class III code for?

Answer 27

Some complement proteins and some cytokines.

Question 28

What does MHC molecules being polygenic mean?

Answer 28

More than one gene for MHC Class I/II molecules.

Question 29

On which chromosome are the MHC genes coded for?

Answer 29

Short arm of chromosome 6.

Question 30

How many alleles does each MHC molecule gene have?

Answer 30

Multiple, with multiple forms in the human population.

Question 31

In mating how many possible combination for each MHC gene?

Answer 31

4

Question 32

Are the MHC gene alleles co-dominant?

Answer 32

Yes

Question 33

What makes tissues/organs histoincompatible?

Answer 33

Mismatched MHC molecules.

Question 34

What is an ideal donor and why for organ transplants?

Answer 34

Identical twins, 100% matched MHC.