T cells

Question 1

where does T cell gene rearrangememt take place?

Answer 1

in the thymus

Question 2

how do T cells move within the thymus?

Answer 2

T cells move from venules into the cortex, then enter the medulla prior to leaving the thymus

Question 3

does negative or positive T cell selection occur first?

Answer 3

Positive selection occurs first and then negative selection

Question 4

what are the stages of T cell progression?

Answer 4

Maturing T cells progress through a double negative to double positive stage to single positive stage (CD4+ or CD8+)

Question 5

what supports expression of a T cell rearranged Beta chain?

Answer 5

Supported by an invariant pre-TCR pTalpha)

Question 6

what happens if the T cell beta chain is successfully expressed?

Answer 6

The alpha chain then undergoes recombination

Question 7

what is the order of chain rearrangment in maturing T cells?

Answer 7

the beta-TCR chain is arranged first and then the alpha-TCR chain

Question 8

what do double positive thymocytes mature into?

Answer 8

CD4+ or CD8+ T cells

Question 9

what confines T cell receptors?

Answer 9

Their ability to only recognise MHC plus peptide

Question 10

What happens following thymic selection of T cells?

Answer 10

The T cell receptors are less variable in shape than antibody

Question 11

what is a requirement of antibody?

Answer 11

Antibody must be able to recognise an almost infinite variety of shapes

Question 12

what is CD3 comprised from?

Answer 12

Zeta, epsilon-gamma and epsilon-delta chains

Question 13

what charge is the TCR?

Answer 13

T cell receptors are positively charged and so attract stuff

Question 14

what mediates the association between different TCR molecules?

Answer 14

The charge difference in transmembrane domains

Question 15

what do the TCR alpha-beta regions associate?

Answer 15

CD3

Question 16

what are CDRs?

Answer 16

Complementarity Determining Regions

Question 17

how many CDRs do TCRs have?

Answer 17

Three CDR
-CDR1
-CDR2
-CRD3

Question 18

what is the role of CDR1 and CDR2 in TCR?

Answer 18

mainly contact MHC

Question 19

what is the role of CDR3 in TCR?

Answer 19

Contacts mainly peptide

Question 20

what encodes CDR1 and 2 in TCR?

Answer 20

encoded by V genes

Question 21

what encodes CDR3 in TCR?

Answer 21

encoded by J junctions (alpha chain) of DJ junction (beta chain)

Question 22

what generates diversity in the TCR gene structure?

Answer 22

Nucleotides are randomly added at the junctions

Question 23

what is the role of iNK-T cells?

Answer 23

recognition of non-peptide ligands
important in cytokine secretion
- these are not natural killer cells

Question 24

what is the function of alpha-beta T cells?

Answer 24

recognise MHC+peptides

Question 25

what is the function of gamma-delta T cells?

Answer 25

recognise CD1 + glycolipids

Question 26

what is the function of NK-T cells?

Answer 26

recognise CD1 + glycolipids

Question 27

what is the function of MAIT cells?

Answer 27

recognize MR1 + Vitamin B metabolite

Question 28

what are CAR T cells?

Answer 28

Chimeric Antigen Receptor T cells

Question 29

what is the role of CAR?

Answer 29

to bind surface tumour antigen and activate T cell

Question 30

how are CAR T cells engineered?

Answer 30

To express CAR comprised of tumor-binding variable antibody fragments (scFv) scFv is fused to T cell signalling components in cytoplasm

Question 31

How do T cells mediate cell death?

Answer 31

release of granzyme/perforin, or by cytokines destroying tumour niche

Question 32

In CAR T cell response, what activates T cells?

Answer 32

Aggregation of cytoplasmic domains of CD28 and CD3zeta

Question 33

how are CAR T cells made?

Answer 33

- Splice antibody Heavy and Light chain variable domains of anti-cancer antibody onto cytoplasmic domains of CD3-zeta and CD28 - transduce patients T cells with chimeric construct -This hardwires T cells to attack the cancer