T cells and TCR arrangement

Question 1

Where are T cells produced and where do they mature?

Answer 1

Originate from Haematopoeitic cells in the bone marrow
These precursors migrate to thymus for maturation, where they are called thymocytes.

Question 2

What does T-cell maturation in thymus involve?

Answer 2

1- Rearrangement of T-cell receptor - The genes for the T cell receptor (TCR) undergo rearrangement to generate diversity.
2- Selection
Positive selection: Thymocytes that can bind self-MHC (Major Histocompatibility Complex) survive → MHC restriction (ensuring T cells recognize self-MHC).
Negative selection: Thymocytes that bind too strongly to self-peptides undergo apoptosis → self-tolerance (to prevent autoimmunity).

Question 3

What % of thymocytes survive and enter the bloodstream as mature T cells?

Answer 3

3-5%

Question 4

What is a T cell receptor?

Answer 4

Membrane- bound glycoprotein similar to Fab fragment

Question 5

How many polypeptide chains is the T cell receptor made up of? and which chains is it made up of?

Answer 5

2
Either Alpha and Beta
Or