Flashcards in L12 Deck (27)
How many signals do naive T cells need for activation? Effector T cells? What happens in each step?
Naive = 2 signals
- MHC & costim
- MAKE granules
Effector = 1, MHC
- Granule exocytosis
What changes occur to a draining lymph node?
Recruit lymphocytes - REGARDLESS of antigen specificity
Via selectins and integrins upregulated on HEVs
What are 3 important T cell receptors for lymph node honing? Explain their significance in context the steps towards diapedesis.
CD26L (selectin receptor)
- Binds L selectin on HEV
CCR7 (chemokine receptor)
- Binds CCL12/21 on HEV
LFA1 (integrin receptor)
- Binds ICAM on HEV
What is the significance of chemokine activation of vascular walls?
Inside out signaling
Integrin receptor changes from low --> high affinity
Get FIRM adhesion
What changes are made to recruit cells to specific tissues?
Modify chemokine receptor for tissue specific chemokines
What cytokine do CD8 T cells secrete? What is the fxn of this cytokine?
Improves macrophage phagocytosis & inflammation
How do CD8 create MEMORY?
ADD CD4 to normal CD8 activation by DC
1. CD4 & CD8 recognize antigen on same DC
2. DC licensing
What is DC licensing?
CD40L from CD4 T cells or inflam signals (like TLRs on DCs) modify a DC to make it provide optimal help for CD8s
What are the 2 ways CD8 cells can actually kill cells?
1. Perforins + granzymes
2. Fas/FasL --> (suicide mechanism) DNA breakdown via caspases
Or some combo of both
What is the disease resulting from perforin deficiency?
Hemophagocytic lymphohistiocytosis (HLH)
- Genetic or acquired
- CD8s get revved up but can't do anything about it --> secrete INF gamma and get inflam, stimulate macrophages
- Splenomegaly, fever, etc
- High levels of inflam cytokines in blood
How could you treat HLH?
+Ab against INF gamma - block macrophage recruitment and toxicity
Are CD8 cells one and done killers?
No - can kill multiple targets
As long as have enough granules
What cytokines make Th1 cells?
What is the function of Th1 cells?
Fight intracellular pathogens
What cytokines do Th1 cells secrete? What cells are helped by this?
What cytokines make Th2 cells?
What is the function of Th2 cells?
What cytokines do Th2 cells make? What cells are helped?
IL4 & 13
Mast cells, eosinophils, basophils
What cytokines make Th17 cells?
What is the function of Th17 cells?
What cytokines do Th17 cells make? What cells are helped?
What cytokines make Tregs? What is the molecular mechanism?
What cytokines do Treg make?
What Abs do Th1s influence the creation of? Th2?
Th1 = IgG 1 & 3 (opsonize)
Th2 = IgE & neutralizing Abs
What is the name for macrophages activates by Th1 cells?
Delayed type 4 hypersensitivity (DTH)
What is Job's syndrome?
Lose STAT3 fxn
= primary immnodeficiency
Hyper IgE - unclear why