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21 Cards in this Set

  • Front
  • Back
T/F - T-cells bind to free antibodies.
Where in the thymus do immature T-cells enter?
Corticomedullary Junction/Cortex
Double negative T-cells reside where in the thymus?
Subcapsular region
Double positive T-cells reside where in the thymus?
Cortex region
Mature T-cells reside where in the thymus?
Medullary regions
Thymocyte & Stromal cell interaction allows for what? x2
1. Induction of developmental signals
2. Proper TCR specificity
What are the phases between stem cell to mature T-cell?
1. Stem cell
2. Double negative
3. Double positive
4. Single positive
5. Mature T-cell
Describe the changing phenotype of the developing T-cell during the Double Negative phase?
CD 44 expressed, CD 25 not
CD 44 expressed, CD 25 expressed
CD 44 low expression, CD 25 expressed
CD 44 not expressed, CD 25 not expressed
When do we see the pre-TCR protein?
In the double negative phase, after CD44 and CD 25 are positively expressing, but before proliferation
When (what phase) does the beta chain arrangement take place?
During the Double Negative phase
When (what phase) does the alpha chain arrangement take place?
During the Double Positive phase.
What needs to occur for alpha chain arrangement to occur?
The beta chain must be correctly arranged.
When (what phase) do we see a TCR on a T-cell?
During the Double Positive phase
Positive selection occurs where?
On Thymic Epithelial cells
Positive selection occurs when?
At the CD4+/CD8+ stage
Positive selection provides what?
A "rescue signal" from apoptosis.
Death by neglect occurs at what stage?
CD4+/CD8+ stage
Which cells get Death by neglect?
Cells with no TCR affinity for self MHC + self peptides
When does negative selection take place?
CD4+/CD8+ stage
What does Negative Selection select against?
Cells with too HIGH TCR affinity for self MHC + self peptides.
What is the net effect of selection?
T-cells with low affinity for anti-self MHC + self peptide reactivity.