Term
| Describe the process of T-cell activation by DCs (4) |
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Definition
1. DC presents antigen to Th (T helper) cell
2. Th cell proliferates & differentiates
3. Th cells which have high binding affinity for the antigen become memory T cekks
4. Cells with lower threshold are released, undergo apoptosis |
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Term
| How are T-cell subsets distinguished? (4) |
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Definition
-type of TCR they express (alpha/beta vs gamma)
-accessory molecule expressions (CD4+ vs CD8+)
-cytokine profile
-function |
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Term
| The majority of mammalian T cells are... |
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Definition
| MHC-restricted alpha/beta T cells |
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Term
| The majority if neonatal ruminants & pig T-cells are... |
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Definition
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Term
| What stabilizes the alpha and beta chains between TCRs? |
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Definition
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Term
| Are the amino acid sequences of ligand-binding TCR domains variable or constant? |
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Definition
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Term
| Ligand-binding variable domains of T cells are also called... |
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Definition
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Term
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Definition
| determine shape of the antigen-binding groove of the TCR, which defines the antigen specificity & binding affinity of the cell |
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Term
| What are the components of a TCR complex? |
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Definition
-trans membrane CD3 molecules
-costimulatory CD4 or CD8 molecules
-TCR |
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Term
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Definition
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Term
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Definition
| MHC class I on all cell types |
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Term
| Is CD40 on B cells expressed constitutively or inducibly? |
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Definition
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Term
| Is CD40 on macrophages expressed constitutively or inducibly? |
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Definition
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Term
| Describe the bi-directional communication that takes place as a result of an interaction between an APC & T-cell |
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Definition
1. CD40 on B cell/macrophage ligates with CD40 on T cell
2. Signal to T cell induces CD28 expression
3. Signal to APC induces CD80 or CD86 expression, IL-1, TNF-alpha, IL-6, IL-8 & IL-12
4. APC CD80/86 ligates with T cell CD28 induces CD152 expression by T cell
5. CD152 has a higher binding affinity than CD28, outcompetes it in a negative feedback to terminate T cell response |
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Term
| DC1 and M1 macrophages produce ____ which promotes differentiation of Th1 cells |
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Definition
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Term
| What does DC2 produce to promote Th2 cell differentiation? |
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Definition
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Term
| What DC products promote differentiation of Tregs? |
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Definition
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Term
Match the following together:
APC CD58
APC CD54
ICAM-1
LFA-3
T-cell CD2
T-cell CD11a
T-cell CD18 |
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Definition
CD58 / LFA-3 / CD2
CD54 / ICAM-1 / CD11a & CD18 |
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Term
| What are the components of the immunological synapse? What do each contain? |
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Definition
cSMAC (TCR complex components, co-stim molecules)
pSMAC (CD45 & adhesion molecules)
outer pSMAC (CD43) |
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Term
| What is the role of the immunological synapse? |
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Definition
| forms a stable bond between cells, concentration signals for communication between APC & T-cell |
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Term
| What happens after an antigen binds to the TCR? |
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Definition
1. CD3 molecules on lipid rafts assemble
2. ITAMS on CD3 act as TK docking sites
3. CD45-CD45R activate TK
4. Src-kinases phosphorylate ITAMs, allowing ZAP-70 to bind |
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Term
| TKs are part of the ____ family |
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Definition
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Term
| Describe the first signaling pathway which might be followed after ZAP-70 phosphorylation (5) |
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Definition
1. ZAP70 activates PLC, producing DAG & ITP
2. ITP triggers Ca release which activates calcineurin
3. NF-AT is dephosphorylated, enters nucleus
4. NF-AT interacts w AP-1 inducing T-cell gene transcription
5. DAG & Ca+ activate PKC, phosphorylating IkB, allowing NF-kB to enter nucleus and induce transcripton |
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Term
| Describe the second signaling pathway which might be followed after ZAP-70 phosphorylation |
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Definition
| ZAP70 activates PKC leading to NF-kB activation |
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Term
| Describe the third signaling pathway which might be followed after ZAP-70 phosphorylation |
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Definition
1. ZAP70 activates Ras
2. Fos is activated
3. CD28 activates Jun
4. Fos & Jun bind to form AP-1 which interacts with NF-AT |
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Term
| Which requires more complexes between the MHC & TCR in order to activate a Th-cell, MHC Class I or MHC Class II? |
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Definition
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|
Term
True or False
High concentrations of antigens alone are enough to activate a T cell |
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Definition
| true but takes longer to occur |
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Term
| How do co-stimulatory molecules reduce the time required to activate a T cell? |
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Definition
| they lower the threshold for activation, so less antigen is required |
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Term
| Streptococcus, staphylococcus, mycoplasma and the rabies virus all produce.... |
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Definition
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Term
| What do superantigens do? |
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Definition
facilitate polyclonal T-cell activation by creating a very strong bond between the MHC and TCR chain
-leads to massive T cell activation & toxic shock syndrome, or T-cell anergy which dulls the immune response in future exposures |
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Term
| Which t-cell subpopulation is anti-inflammatry? |
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Definition
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Term
| Which t-cell subpopulation targets parasites & tumor cells |
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Definition
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Term
| Which t-cell subpopulation targets extracellular bacteria & parasites |
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Definition
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Term
| Which t-cell subpopulation targets intracellular bacteria fungi & viruses |
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Definition
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Term
| Which t-cell subpopulation targets extracellular bacteria & fungi? |
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Definition
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Term
| Describe the cross-regulation that occurs if IL-12 is present when naive T-cells are differentiating |
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Definition
-differentiated into Th1 cells
-IFN gamma is produced
-Stat1 is expressed
-T-Bet is expressed
-IFN- gamma is expressed, shuts down GATA-3 to inhibit IL4 & IL5 expression |
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Term
| Describe the cross-regulation that occurs if IL-4 or IL-13 is present when naive T-cells are differentiating |
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Definition
-differentiate into Th2
-more IL4 is produced
-Stat6 is induced which indues GATA-3
-IL4 & IL5 expression is induced shutting down T-bet expression
-IFN-gamma expression is inhibited |
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Term
True or False
All gamma/epsilon T cells are capable of MHC class II independent antigen recognition |
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Definition
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Term
| Ruminant WC1+ gamma/epsilon T cells are involved with what? What do they produce? |
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Definition
innate immunity
IL-12 and IFN-gamma |
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Term
| Ruminant WC1- gamma/epsilon T cells are involved with what? |
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Definition
| regulating the immune response |
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Term
| Memory T-cells don't produce ___ and are therefore more resistant to apoptosis |
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Definition
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Term
| CD4+ T cells rely on _____ for survival |
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Definition
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Term
| CD8+ T cells rely on ____ for survival |
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Definition
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Term
Are naive T cells positive or negative to the following?
CD45R
L-selectin
CD44 |
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Definition
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|
Term
Are memory T cells positive or negative to the following?
CD45R
L-selectin
CD44 |
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Definition
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Term
Which of the following are associated with T cells, NK cell and B cells?
lck
lyn
fyn |
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Definition
T cells & NK cells: lck & fyn
B cells: lyn & fyn |
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