Term
| What are the six phases for T cell activation? |
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Definition
1) Recognition
2) Activation phase
3) Clonal expansion / differentiation
4) Effector phase
5) Decline
6) Memory |
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Term
| What is the purpose of a TH1 cell? Which cytokines do they secrete? |
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Definition
Purpose:
- involved in DTH
- activate CTLs
Cytokines:
- IL-2
- IFN-gamma
- TNF-beta
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Term
| What is the purpose of a TH2 cell? Which cytokines do they secrete? |
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Definition
Purpose: Help B cell activation
Cytokines: IL-4, 5, 6, 10 |
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Term
| What percentage of circulating T cells are memory cells? Do memory cells require a costimulatory signal to respond? |
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Definition
0.01% memory cells
Doesn't require costimulation |
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Term
| What two signals must be present for T cell activation? |
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Definition
1) MHC-antigen must interact with TCR
2) Co-stimulatory signal - B7 with CD28 |
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Term
| What is the third signal of T cell activation? |
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Definition
| IL-2 - brings T cells from G1 to S phase in mitosis. |
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Term
| To what is TCR complexed? |
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Definition
CD3 heterodimers -gamma/delta with epsilon
CD3-zeta homodimer
contains 1-3 ITAMs for signalling. |
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Term
| Which cells are the only cells which constituitively express B7-1? |
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Definition
| Dendritic cells - the most helpful for activating T cells |
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Term
| Which professional APCs consitutively express MHC IIs? |
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Definition
DCs and B cells
Activated macs can be induced to express MHCs. |
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Term
| Which professional APCs consitutively express B7? Which cells can be induced to express B7? |
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Definition
DCs constitutively express B7
Activated macs and B cells can be induced. |
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Term
| Which cells can activate naive T cells? |
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Definition
| DCs and activated B cells |
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Term
| What immunodeficiencies can be caused by defects in the T cell activation pathway? |
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Definition
ZAP-70 --> SCID-like disease
Bruton tyrosine kinase (BTK) --> Bruton's agammaglobulinemia
Adapter that binds T and B cells --> X-linked immunoproliferative disease - EBV susceptibility
CD40L --> X-linked hyper IgM |
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Term
| What are two potent immunosuppressive drugs? How do they work? |
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Definition
| Cyclosporin A and FK506 --> blocks calcineurin activation of NFAT, thus blocking IL-2 |
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Term
| What molecules does IFNalpha Receptor associated with? |
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Definition
| IFN-alpha Receptor associated with 2 JAKs: Jak-1 and Tyk2 |
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