Thymic emmigration

Question 1

Peripheral phenotype of RTE

Answer 1

Reduced capacity for proliferation
Downregulate CD24
Upregulate: Qa-2, CD25

Question 2

Following positive selection

Answer 2

DP will upregulate CD69 and CCR7. This allows them to migrate to the medulla, where they remain sensitive to apoptosis for 2 days and emigrate after 4

Question 3

Time from SP-Emmigration

Answer 3

4-5 days as an upper estimate because it was done with rag2 gfp and it doesn’t account for the potential prollifer

Question 4

CCR4 and CCR9 expression

Answer 4

high on CD69+ CD24+ (CD4s)

Low on CD69- CD4SP

Question 5

Pertussis toxin treatment

Answer 5

Prevents SP cells from crossing the cortico medullary junction
(inhibits gprotein coupled receptors

Question 6

CCR7

Answer 6

Mediates migration to the medulla
deficiency isn’t as complete as pertussis toxin
so other GPCRs are likely driving migration as well
expression driven by TCR engagement

Question 7

CCR9

Answer 7

Retention in cortex?

Question 8

CCL25

Answer 8

CCR9 ligand

Question 9

PlexinD1

Answer 9

thought to inhibit CCR9/CCL25 signaling allowing CD4 SP cells to migrate to the medulla

Question 10

CCR4

Answer 10

Upregulated following positive selection
Ligands are CCL17 and CCL22
no obvious disruption in CD4/CD8 develpment or migration in CCR4-/- mice

Question 11

CCL17

Answer 11

Ligand for CCR4

Question 12

CCL22

Answer 12

Ligand for CCR4 - expressed on CD80hi aire+ mTECs

Question 13

CCR3

Answer 13

expressed on NKT cells and is required for retention in the thymic medulla