T cell development

Question 1

95% of T-cells have _/5% have _

Answer 1

αβ-chains/γδ-chains

Question 2

CD3

Answer 2

Associates with TCR, contains ITAMS

Question 3

TCR simultanously binds two things. Which?

Answer 3

MHC and peptide

Question 4

TCR co-receptors

Answer 4

CD4 and CD8. Strengthen binding to MHC and carries Lck for ITAM phosphorylation

Question 5

CD8 cells can bind

Answer 5

MHCI on all cells

Question 6

CD4 cells can bind

Answer 6

MHCII on immune cells, APCs

Question 7

T cell devolpment hapens in

Answer 7

The thymus

Question 8

Four stages of T cell maturation

Answer 8

Stage 1: Stem cells arrive in the thymus, stage 2: diverse TCRs are generated by germline DNA rearrangement, stage 3: Positive selection of T cells capable of somewhat binding peptides on MHC, stage 4: negative selection of T-cell that binds too strong to self-antigen.

Question 9

β chain rearrangement steps

Answer 9

DJ-joining, V-DJ joining

Question 10

γδ-chain rearrangement

Answer 10

Happens as a race; if they make a useful receptor before β or α chain is made, the T cell becomes a γδ T cell.

Question 11

β chain is tested how

Answer 11

By pairing with a surrogate protein and forming of pre-T cell receptor. If superdimer is made by pre-TCR, CD3 clustering sends a signal to pause rearrangement, proliferate and express CD4 and CD8

Question 12

Double positive

Answer 12

T cell that expresses CD4 and CD8

Question 13

Junctional diversity

Answer 13

Is generated in both α and β chain.

Question 14

P-nucleotides

Answer 14

From palindromic sequences in junction

Question 15

N-nucleotides

Answer 15

From random nucleotide addition by TdT

Question 16

Positive selection

Answer 16

Binding of MHCI or II on epithelial cells in thymus causes survival and CD4/8 determination in T cells

Question 17

Failure to bind MHCI or II results in

Answer 17

Continued α chain rearrangements, made possible by lots of V and J segments.

Question 18

Negative selection

Answer 18

Too tight binding to MHC on dendritic cells and macrophages in thymus causes apoptosis.

Question 19

Natural Treg cells

Answer 19

Tight but not too tight programs T cells to become immunosupressive - peripheral tolerance.