0502 T cell development

Question 1

Which MHC class do TCR bind to (also list which specific T cells)

Answer 1

Both. CD4 T cells bind to MHC2and CD8 T cells bind to MHC1

Question 2

Name the 7 stages of T cell development from T progenitor cell to the cytotoxic and helper T cells

Answer 2

T lymphoid progenitor cell, DN1, DN2, DN3, DN4, DP, finally CD4 or CD8 cell

Question 3

What is the significance of the medulla, cortex and Hassall corpuscle area

Answer 3

The cortex region is where immature thymocytes develop. The medulal region is where mature T cells reside then migrate to the periphery. The hassal region is the site of cell destruction

Question 4

List 3 non-lymphoid cells that thymocytes interact with

Answer 4

Thymic epithelial cells, intrathymic dendritic cells and Notch 1

Question 5

List the 3 most functional (important?) cell-surface proteins that need to be expressed during T cell development

Answer 5

CD3 (forms complex with TCR). CD4 and CD8 (co-receptor requried for recognition by TCR of antigenic peptides)

Question 6

How many stages are there for double negative thymocytes

Answer 6

4 = DN1, DN2, DN3, DN4

Question 7

What is the earliest stage that CD3 is expressed on the cell surface

Answer 7

DN3

Question 8

What is the earliest stage that Pre-TCR is expressed on the cell surfface

Answer 8

DN3

Question 9

What is the complete TCR first expressed on a T cell? What two components need to be present

Answer 9

Double positive stage. Both CD4 and CD8 need to be present

Question 10

Describe positive selection of developing T cells? What is the main function of positive selection

Answer 10

Positive selection involves survival of self-peptide-self-MHC binding T cells and apoptosis of those that don’t recognise self-MHC. The main function is to ensure functional T cells that bind to antigen:MHC complex

Question 11

Describe negative selection of developing T cells. What is the main function of negative selection

Answer 11

Negative selection is apoptosis of cells that strongly bind to self-peptide-self-MHC. The main function is to ensure functional T cells that recognise non-self antigens

Question 12

Which proteins are expressed during TCR alpha chain gene rearrangement

Answer 12

RAG-1 and RAG-2

Question 13

Describe beta selection of developing T cells. What is the main function of beta selection

Answer 13

Beta selection is the process where cells with a functional pre-TCR (invariant alpha chain and functional beta chain) survive. Its function is to ensure cells that can form functioning TCRs continue in development

Question 14

What are the 3 selection processes that T cells undergo (in order)

Answer 14

Beta selection, positive selection and negative selection