Lecture 16. T-cell Development and Thymic Education

Question 1

What does every T-cell have ?

Answer 1

A TCR of a different specificity

Question 2

What is MHC restriction ?

Answer 2

TCR can only recognise peptide presented by MHC

Question 3

What ensures that T-cells are able to mount an adaptive immune response against any pathogen/antigen ?

Answer 3

The potential to generate 10^9 specificities

Question 4

Where do T-cells develop and are selected ?

Answer 4

Thymus

Question 5

What happens to T-cells specific for self-antigens ?

Answer 5

Must be deleted to avoid autoimmunity

Question 6

What is the only cell not found in bone marrow ?

Answer 6

T-cell

Question 7

What is the surface marker of the T-cell progenitor ?

Answer 7

CD2+

Question 8

What are chemotactic cytokines ?

Answer 8

Family of around 4 molecules that regulate trafficking of leukocytes by their interaction with transmembrane, G-couples receptors

Question 9

What do chemokines do in infection and inflammation ?

Answer 9

1. Recruit leukocytes
2. Direct movement of progenitors and mature cells
3. Promote wound healing, angiogenesis, metastasis and organogenesis of primary and secondary lymphoid organs

Question 10

What is the chemotactic attractant for neutrophils ?

Answer 10

IL8

Question 11

What are the cytokines that drive T-cell development ?

Answer 11

IL7, IL2 and IL15

Question 12

What is apoptosis marked by ?

Answer 12

DNA fragmentation

Question 13

What is terminal deoxynucleotidyl transderase used for ?

Answer 13

Annealing

Question 14

Where do thymocyte progenitors enter ?

Answer 14

The thymus in the subcapsular region

Question 15

How do T-cells develope in the thymus ?

Answer 15

1. Become double negative
2. Proliferate and differentiate to double positive
3. Migrate to cortex
4. Positive selection (self-MHC restricted)
5. Migrate to cortico-medulary junction
6. Negative selection (self tolerant)
7. Mature to single positive T-cells

Question 16

What does AIRE do ?

Answer 16

Generates delf antigens of all tissue types

Question 17

What is DiGeorge syndrome ?

Answer 17

Have B-cells but no T-cells

Question 18

What happens during maturation of T and B lymphocytes ?

Answer 18

Go through cycles of proliferation and expression of antigen receptor proteins by gene recombination

Question 19

What happens at the end of maturation ?

Answer 19

Positive and negative selection

Question 20

What are all thymocytes programmed to do ?

Answer 20

Die

Question 21

What is positive seletion mediated by ?

Answer 21

Thymic epithelial cells

Question 22

What is negative selection mediated by ?

Answer 22

Dendritic cell and macrophages

Question 23

What is the purpose of seletion events in the thymus ?

Answer 23

To ensure that T-cells entering the peripherery are self MHC restricted and self tolerant

Question 24

What does positive selection ensure ?

Answer 24

T-cells can recognise peptides in the context of own MHC - only low affinity binding

Question 25

What does negative selection ensure ?

Answer 25

T-cells whose TCR binds self antigen with high affinity are deleted, those with weak affinity survive