Lecture 8 & 9- Cytokines and Naive T cell Activation Flashcards
(39 cards)
Which cell types produce IL-1? Why do they produce it?
Mononuclear phagocytes (main) Leukocytes Fibroblasts Vascular endothelial cells (ECs) In response to LPS, TNF, IL-1 or CD4+ T cell stimulation
What does IL-1 do?
Increases IL-2 synthesis Promotes leukocyte adhesion to EC Systemically - cachexia
Give three functions of TNF alpha
Any of: - Increases expression of adhesion molecules on leukocytes and vascular ECs - increases permeability of endothelium - activates microbicidal activity of macrophages and neutrophils - induces release of IL-1, IL-6, itself - increases class I and II MHC expression - increases core body temp (systemic) - induces acute phase protein synthesis - can cause circulatory collapse and DIC if excessive levels
What induces TNFalpha release?
TNFalpha signaling, or LPS binding TLR4
What stimulates IL-6 release?
IL-1 and TNFalpha signalling
What does IL-6 do?
Stimulates acute phase protein synthesis, promotes B cell differentiation
What is the main function of IL-8? Give one cell type that makes it.
Chemotaxis and activation of neutrophils e.g antigen-activated T cells, LPS activated phagocytes, fibroblasts, ECs, platelets
What is the main function of IL-12? Name the cell types that produce it.
Macrophages and dendritic cells Induces Th1 differentiation, activates NK cells
What are the two main functions of IL-17? Which cell types makes it?
Th17 cells (in response to IL-23 from dendritic cells) Recruit macrophage and neutrophils to site of inflammation Release of IL-1, IL-6, TNF alpha from macrophage
What part of the bacteria does C reactive protein bind? What function does this promote?
Binds phosphocholine on bacterial surface Promotes phagocytosis (opsonisation)
Which are the type 1 interferons? Which cell types produce them?
IFN alpha and IFN beta Most cells
What event induces type 1 IFN synthesis and release?
Binding of TLR3 by dsRNA Or, type 1 IFN signaling
Give 4 intracellular effects of type 1 IFN signaling
- Mx protein induced, traps viral proteins for degradation 2. Protein kinase R initiates antiviral signaling pathways 3. RNase cleaves viral RNA 4. MHC I expression increased to boost CD8+ T cell function
What effect does type 1 IFN have on NK cells?
Activates them
Which cells produce IL-2?
CD4+ and CD8+ T cells
What major effect does IL-2 have on T cells?
If they express the high-affinity IL-2-R, it induces proliferation
What are four other effects of IL-2?
IFN-gamma release by T cells TGFbeta release by T cells B cell stimulation NK cell stimulation
Which cell types produce IL-4? Which inflammatory pathway absolutely requires it?
Produced by CD4 T cells, NK cells, mast cells Required by B cells for class switching to IgE
Name one cell that produces TGFbeta. What are two functions?
Treg cells Stimulates angiogenesis, inhibits T cell proliferation, required for class switch to IgA
Which cell types produce IFN gamma? In response to what?
Th1 and CD8 T cells, in response to antigen encounter and IL-2
List four functions of IFNgamma
Any of: - potent activator of phagocytes and neutrophils - induces synthesis of enzymes of the respiratory burst - induces TNFalpha secretion - activates NK cells - increases MHC I and II expression - promotes B cell differentiation - promotes IgG2a synthesis (opsonising)
Which cell types produce IL-5? Which inflammatory pathway is it important for?
Th2 and mast cells Stimulates eosinophil growth; important for helminth immunity
How are chemokines classified?
Based on configuration of two cysteine residues at the N terminus
What are the five types of cytokine receptors?
- Immunoglobulin superfamily 2. Class 1 cytokine receptors (haematopoetin family) 3. Class 2 cytokine receptors (interferon family) 4. TNF receptors 5. Chemokine family receptors (G protein coupled)
