Important cytokines Flashcards
IL-1
Alarm cytokine, fever
TNF-alpha
Alarm cytokine
Alarm cytokines
IL-1, TNF-alpha
Function: released by activated macrophages; massive increase in vascular permeability–>severe drop in blood pressure which could be fatal (SEPTIC SHOCK)
IL-6
Triggers acute phase protein production from LIVER
IL-8
Chemotactic for neutrophils
IL-12
Directs adaptive immunity, activates NK cells
What activates NK cells?
IL-12,
IFN (all types)
Functions of Th1 cells
- Macrophage activation
- DTH
- Help for CD8 cells
- Downregulation of Th2 responses
Th1 macrophage activation cytokines
IFN-gamma, TNF-a
Th1 DTH cytokines
IL-2, IFN-g, TNF-a, IL-3, GM-CSF
Th1 CD8 help cytokines
IL-2
Th1 downregulation of Th2 responses cytokine
IFN-g
Th2 functions
- B cell proliferation
- B cell differentiation and Ig class switch
- Downregulation of TH1 responses
Th2 B cell prliferation cytokines
IL2, IL-4, IL-5
Th2 B cell differentiation and Ig class switch cytokines
IL-2, IL-4, IL-5, IFN-g
Downregulation of Th1 response by Th2 cytokine
IL-4
Cytokines produced by Th-17
-IL-17
• Protective against some bacterial infections; clear bacterial infections through activation of neutrophils and macrophages
Mediate pathogenic responses in autoimmune diseases such as arthritis
Follicular T helper cells
Produce IL-21
• reside in B cell follicles and induce B cells to produce antibodies
• Essential for generation of isotype-switched antibodies
• Triggers formation of germinal centre
Tfh (Follicular helper T cells)
• (B cell moves to edge of follicle and Tfh expressed CD40L, secretes IL-21 and IL-4 –> trigger formation of germinal centres –> affinity maturation)
4 mechanisms of peripheral tolerance
RAID
Cytokines produced by Treg
IL-10
TGF-B
IL 35
TF in Treg
FOXP3
Treg cells mechanisms
- secretion of immunesuppressive cytokines
- inactivation of DC or responding lymphocytes
- absorb IL-2 produced by DC (express IL-2 receptor)
Th1 vs Th2
Th1=pro inflammatory
Th2=pro allergic
IL-10
- Key anti-inflammatory cytokine
- Multi-functional
- Acts on RANGE of cells which have IL-10 receptor
- BLOCKS pro-inflammatory cytokine synthesis (e.g. TNF, IL-6, IL-8, IFN gamma)
- Downregulates macrophages
- BUT viruses such as EBV mimic IL-10 action :(
Cytokine cross-regulation
- Th1 inhibits Th2 and vice versa (they ONLY inhibit the other!)
- Th17 and Tregs inhibit ALL others
- all have self-positive feedback i.e. they produce cytokines that stimulate the same T cell to produce more of that cytokine
Cytokines and macrophages
Different cytokines trigger development of DIFF macrophages (proinflammatory vs antiinflammatory)- can focus the TYPE of response
