3/3/17 GERMAN T Cell Development TEST #2 Flashcards
Where do T-cell progenitors develop?
-Bone marrow
Where does positive and negative selection for T cells occur?
-Thymus
What are developing T cells within the thymus called?
-Thymocytes
What type of T cells do not express CD4 or CD4 co receptors?
-Gamma:Delta T cells
Where does TCR development occur within the thymus?
-Cortex
As the T cell matures from a double negative to a double positive where does it move from and to within the thymus?
-Cortex to medulla
T/F The thymus involutes with age
True
What is the half life for a CD4 cell?
4.2 years
What is the half life for a CD8 cell?
-6.5 yrs
T/F T cell progenitors don’t commit until they reach the thymus
True
T cells determine they are in the right spot by what type of signaling?
Notch 1
What is a B cell transcription factor?
-Pax-5
What type of T cell is a double-negative?
-Pre-T cell
If a T cell rearranges the Gamma:Delta before the Beta what type of T cell does it become?
-Gamma:Delta T cell
If a T cell rearranges the Beta chain first what type of T cell does it become?
-Alpha:Beta T cell
What is the first checkpoint for T cell development?
-Having a Pre-T cell receptor
What is the second checkpoint for T cell development?
-Positive and Negative selection
After you have proliferating pre-T cells what is the next stage of T cell development?
-Double positive
After you undergo positive and negative selection of T cells, what is the next stage of development?
-Single-positive
What dictates T cell lineage?
-Gene rearrangement
If you are going to become and Alpha:Beta T cell what is the first chain that needs to be rearranged?
-Beta chain
Beta chain production drives the expression of what?
- CD4
- CD8
What two regions come together first in the B-chain rearrangement?
-DJ
What type of T cell development stage does the Beta chain rearrangement occur?
-Double negative
What forms Pre-T cell receptors?
-Beta chian rearrangement
When the B chain binds a surrogate alpha chain and creates a super dimer what is recruited?
-CD3 complex
Once the Beta chain has rearranged can the cell still become a Gamma:Delta T cell?
-Yes
In a double negative thymocyte will you have CD4 or CD8?
-No
In a double positive thymocyte will you have CD4 or CD8?
-Yes both
What does positive T cell selection lead to?
-Function TCR
What does Negative T cell selection lead to?
-No self-antigen binding
What does positive selection ensure?
-MHC is bound
In the positive selection process a TCR must bind the MHC within how many days or else it will DIE!!!
3 to 4 days
What is the last type of selection that occurs before a T cell gets released into the periphery?
-Negative selection
Dendritic cells and macrophages present self peptides to T-cells, if it binds excessively what occurs?
-Apoptosis
Where do mature naive T cells enter?
-Blood stream
What are the two major stages of T cell development?
- Double Negative
- Double Positive
When a T cell is a double negative what occurs?
-Beta chain rearrangment
