Term
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Definition
β-chain rearranged first
Surrogate a chain binds to β-chain
Pre-TCR has β-chain and surrogoate
rearrangement of a chain leads to loss of δ-chain |
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Term
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Definition
Appear in fetal thymus.
Do not undergo selection
CD4- & CD8-. Immunosurveilance
Migrate to mucosa and skin, intestines,
lungs
May participate in wound repair. |
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Term
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Definition
Cd4+: secretion of cytokines
Th1(cell mediated) Th2(Humoral)
Cd8+: cytotoxic(CTL)
NKT cells: Express CD3, recognize
glycolipid and glycopeptides presented
on CD1
Found in lymphatic tissue |
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Term
| T-Cell trafficking and induction of B chain rearrangement |
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Definition
CD34+ cell migrates from bone marrow to
thymus. (requires c-kit and CD44 on CLP)
c-kit and IL-7R(pro T)
bind SCF and IL-7(Thyroid cell)
Induces TCR gene arrangement |
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Term
| Cortex and medulla TCR development |
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Definition
Cortex:
TCR and CD3 expression
Induction of expression of CD4 & CD8
Positive selection: MHC recognition ->
CD4 or CD8 commitment
Medulla:
Cell expresses CD4 or CD8
Negative selection: Self-reactive T
cells eliminated |
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Term
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Definition
CD34+ CD 44+ lymphoid progenitor
double negative thymocyte
B Chain rearrange Cd4+ Cd8+. Pre-TCR
a chain rearrangement
Positive selection
Single positive thymocyte |
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Term
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Definition
Positive: αβ T cells by Cortical \
epithelium.
If TCR can bind MHC I or II molecule
then it lives and expresses CD4 or CD*
95% of TCR can not bind MHC and die
CDR1/2 on TCR bind MHC |
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Term
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Definition
Eliminates self-reactive T cells
High affinity = apoptotic cell death
Weak/moderate cell survival
Treg have moderate self antigen binding
T-regs cause anergy of self-reactive
cells in periphery.
T-reg = CD25+, Foxp3+, CD4+ |
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Term
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Definition
Result of negative selection of
self-reactive T cells in thymus and of
self-reactive B cells in bone marrow
AIRE - Treg generation.
AIRE is a transcription factor in
medullarly epitheial cells that help
produce self-tissue specific antigens
Induces FoxP3 |
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Term
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Definition
Mechanisms blocking self-reactive T cells that survived negative selection
Peripheral clonal anergy:
Incomplete signal transduction events
Absence of Costimulation
(APC CD80/86 do not bind Cd28 Tcell)
Immune privileged sites
CD95/CD95L binding -> Apoptosis |
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Term
| Co-stimulation. APC - T-cell |
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Definition
APC Cd80/86 bind to Cd 28 T cell
Signal transduction. |
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