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20 Cards in this Set
- Front
- Back
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TH cell + Ag will stimulate... |
T cells to enter the cell cycle==>IL2R & secretion of IL2 |
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Receptor crosslinking |
Ab + TcR = activation of T cell directly |
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To activate a T cell you need |
Ag, processedand sitting in the MHC and the TcR |
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IP3 |
-mediates release of intracellular Ca++ -an intracellular kinase adds additional phosphate to IP3 → IP4 = opens Ca++ channels on membrane to let in additional Ca++ |
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DAG |
-activates PKC (protein kinase C) -increase affinity for PKC Ca++--> -change in intracellular H+ therefore increases pH/PKC catalysis the phosphorylation of many signaling proteins -CD4,IL-2R, NF-κB, etc |
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PTK-->PLCγ1-->cleaves PIP2-->IP3/DAG |
------- |
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Immediate genes |
NF-κB |
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Early genes |
IL-2, IL-2R,IL-6,IFNy |
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Late genes |
various adhesion molecules |
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use Ca++ ionophores (A23187 or ionomycin) to... |
activate cells w/o TcR -Open Ca++ channels and induce influx of Ca++ -A23187 stimulates IL-2 secretion |
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use PKC activators (i.e., phorbol myristateacetate; PMA) to... |
-Directly activate PKC and initiate the events -PMA stimulates IL-2R expression |
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Ca++ is from... |
intracellular pools, but forsustained levels you do need extracellular Ca++ |
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EGTA |
Gets rid of extracellular Ca++ |
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Ab to TcR |
Found an increase in intracellular Ca++, just like controls |
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PTK |
Interact with the ITAM sequences of CD3 cytoplasmictail -lck, associated with the cytoplasmic tails of CD4 and CD8 -fyn associated with the cytoplasmic tail of the CD3 protein ζ (zeta) |
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activation ofTH cells requires... |
co-stimulatory signalprovided by the APC = surface molecule B7(CD80/CD86) |
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Stimulus needed for full TH cell activation... |
Interaction between TcR and MHC & B7 |
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Signal # 1 (Activation) |
Interaction of a peptide and MHC molecule with aspecific TcR-CD3 complex |
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Signal #2 (Survival) |
Subsequent Ag non-specific co-stimulatory signal byinteractions between CD28 (or CTLA-4) on T cells andB7 (CD80/CD86) on APC |
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Signal #3 (Proliferation &/or Differentiation) |
Directing T-cell differentiation into different subsets ofeffector T cells |
