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21 Cards in this Set
- Front
- Back
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T/F - T-cells bind to free antibodies.
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False
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Where in the thymus do immature T-cells enter?
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Corticomedullary Junction/Cortex
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Double negative T-cells reside where in the thymus?
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Subcapsular region
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Double positive T-cells reside where in the thymus?
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Cortex region
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Mature T-cells reside where in the thymus?
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Medullary regions
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Thymocyte & Stromal cell interaction allows for what? x2
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1. Induction of developmental signals
2. Proper TCR specificity |
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What are the phases between stem cell to mature T-cell?
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1. Stem cell
2. Double negative 3. Double positive 4. Single positive 5. Mature T-cell |
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Describe the changing phenotype of the developing T-cell during the Double Negative phase?
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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 |
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When do we see the pre-TCR protein?
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In the double negative phase, after CD44 and CD 25 are positively expressing, but before proliferation
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When (what phase) does the beta chain arrangement take place?
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During the Double Negative phase
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When (what phase) does the alpha chain arrangement take place?
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During the Double Positive phase.
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What needs to occur for alpha chain arrangement to occur?
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The beta chain must be correctly arranged.
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When (what phase) do we see a TCR on a T-cell?
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During the Double Positive phase
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Positive selection occurs where?
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On Thymic Epithelial cells
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Positive selection occurs when?
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At the CD4+/CD8+ stage
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Positive selection provides what?
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A "rescue signal" from apoptosis.
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Death by neglect occurs at what stage?
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CD4+/CD8+ stage
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Which cells get Death by neglect?
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Cells with no TCR affinity for self MHC + self peptides
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When does negative selection take place?
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CD4+/CD8+ stage
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What does Negative Selection select against?
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Cells with too HIGH TCR affinity for self MHC + self peptides.
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What is the net effect of selection?
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T-cells with low affinity for anti-self MHC + self peptide reactivity.
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