Week 4

Question 1

What are the main roles of T cells ?

Answer 1

Find and kill infected cells
Activate other immune cells
Cytokine production
Co-ordinate and regulate the immune response

Question 2

What are the 4 stages of T cell response?

Answer 2

1) Detect the presence of an infected cell.
2) Pass the external signal across the cell membrane.
3) Activate the relevant biochemical pathway.
4) Produce the cellular response.

Question 3

What type of antigens are used in the MHC class I antigen presentation pathway?

Answer 3

Endogenous

Question 4

What type of antigens are used in the MHC class II antigen presentation pathway?

Answer 4

Exogenous

Question 5

What type of T cells and MHC are used against endogenous antigens.

Answer 5

MHC class I with CD8+ T cells

Question 6

What type of T cells and MHC are used against exogenous antigens.

Answer 6

MHC class II with CD4+ T cells

Question 7

What type of T cells are CD8+ T cells?

Answer 7

Cytotoxic

Question 8

What type of T cells are CD4+ T cells?

Answer 8

Helper T cells

Question 9

How many subunits does the T-cell proper structure have?

Answer 9

4

Question 10

How does the differential structure on alpha and beta chains alter antigen binding?

Answer 10

It does not significantly change antigen binding.

Question 11

When and how does the ITAM receptor on a T cell receptor change?

Answer 11

The structure has a conformational change when an antigen becomes bound to the T cell.

Question 12

What happens when the ITAM receptor on a T cell receptor is activated?

Answer 12

The ITAM will start phosphorylating other proteins.

Question 13

What type of receptors do all T cells have?

Answer 13

CD3

Question 14

How are T cell receptors degenerative?

Answer 14

Many T cell variants recognise the same antigen.

Question 15

What process allows signals to be transduced cross the T cell membrane from the T cell receptor?

Answer 15

Dimerisation

Question 16

What do T cells initially use to bind to APC cells?

Answer 16

Low affinity LFA-1 and CAM-1 interactions.

Question 17

How do T cells begin to have stronger binding with antigen presenting cells?

Answer 17

Binding of T cell receptors signals LFA-1. Conformational changes in LFA-1 increase the affinity and prolong cell-cell contact.

Question 18

What is ICAM-1 recognised by?

Answer 18

LFA-1 protein on T cells.

Question 19

Why do T cells use 2 different receptor types to bind to antigen presenting cells?

Answer 19

This allows binding for a longer amount of time and gives T cells longer to do their jobs and transduce the signal.

Question 20

What are the purpose of CD28 T cell receptors?

Answer 20

Expressed to recognise if the antigen derives from the innate immune response.

Question 21

What are the purpose of CD80 T cell receptors?

Answer 21

They bind to CD28and further strengthen the response and stabilise the cellular interactions.

Question 22

What are the purpose of Ox40L T cell receptors?

Answer 22

They connect to ligands and stabilise the connection and also increase the length of cellular interactions.

Question 23

In resting T cells, are ITAMS phosphorylated or not?

Answer 23

No

Question 24

What causes ITAMS on T cells to become phosphorylated?

Answer 24

Binding of ligands

Question 25

What happens to ITAMS on T cells once a ligand binds?

Answer 25

Binding of the ligands causes phosphorylation of ITAMS when the co-receptor binds to the MHC ligand.

Question 26

How does phosphorylation of a molecule cause activation?

Answer 26

Causes the molecule to become more negatively charged. This may change the shape of the protein and may lead to its activation or inactivation.

Question 27

What atoms carry the largest quantity of negative free energy?

Answer 27

Phosphorus

Question 28

Why are phosphorus atoms used so frequently in cell signalling and activation?

Answer 28

They carry a high amount of negative free energy.

Question 29

What is 'different' about ZAAP protein?

Answer 29

It is not static and can move across the cytoplasm and interact with LAT complexes.

Question 30

What is the benefit of ZAAP in terms of T cells and how does it cause this?

Answer 30

ZAAP can phosphorylate ADAP which then activates a series of proteins and results in intern interactions. This aids cell adhesion.

Question 31

What changes in T cells can be caused by NAFT phosphorylation?

Answer 31

Activation of transcription mechanisms and alteration of gene expression.

Question 32

Why are drugs used to inhibit NAFT?

Answer 32

This gives transplants greater success as the T cells will not attack the transplant

Question 33

How does length of time that cells are bound change the outcome of a response?

Answer 33

Can change gene expression and differentiation of T cells from naive T cells.

Question 34

What is the purpose of transduction in T cells?

Answer 34

To amplify the response

Question 35

Why is IL-2 important in terms of T cell responses?

Answer 35

It can feedback on T cells and cause them to proliferate.