Cytokines Flashcards
Over production of cytokines:
Cytokine Storm
Cytokine families (4):
- Interleukins.
- Colony stimulating factor.
- Interferons.
- TNF.
Interleukins:
Made by leukocytes, having effects on other leukocytes.
Colony stimulating factors:
- Stimulate granulocyte, monocyte and dendritic cell production and differentiation.
- GMCSF, GCSF, MCSF
- Granulocyte Monocyte Colony Stimulating Factor.
Interferons:
- Alpha, beta and gamma
Th1 cells release cytokines which aid:
Cell mediated immunity (CMI)
Th2 cells release cytokines which support:
Humoral immunity
Th17 promotes:
Inflammation
Enhanced by tumors, turns off Th1 release:
Th2
Th1 cells produce cytokines that promote immune responses against intracellular pathogens (2):
- IFN-gamma
2. IL-2
Th2 cells produce cytokines that promote immune responses against extracellular pathogens (4):
- IL-4
- IL-5
- IL-6
- IL-13
Cytokines produced by both Th1 and Th2 cells and use:
- GMCSF and IL-3.
- Act on bone marrow to increase production of leukocytes.
GMCSF:
Increased production of granulocytes and macrophages and dendritic cells on the hematopoietic cells.
The alpha chain of cytokine receptors:
Determines specificity and is different for each receptor type.
Binding of cytokine to receptor:
- Internalization.
- Re-expression of new receptors within a few hours.
IL-2 receptor is composed of:
3 subunits: alpha, beta and gamma chains.
Low affinity IL-2 receptor:
Monomeric, IL-2R-Alpha
Medium affinity IL-2 receptor:
Dimeric, IL-2R-AlphaBeta
High affinity IL-2 receptor:
Trimeric, IL2R-AlphaBetaGamma
Chemokines:
Cytokines that induce cell movement along a gradient.
- Act as inflammatory mediators AND mediators of constitutive leukocyte migration.
Two major types of chemokines:
- Inflammatory
2. Lymphoid
Inflammatory chemokines:
- Not expressed in normal tissues.
- Stimulate inflammation.
- Activity regulated by chemokine expression.
Lymphoid chemokines:
- Expressed in lymphoid organs.
- Mediate lymphocyte recirculation.
- Maintain lymphoid structures.
- Constitutively expressed.
- Action regulated by receptor expression.
IL-1
Monocytes and Activated macrophages.
- Increase blood flow.
- Increase expression of adhesion molecules.
- Fever.
- Increase cytokine production.
- Neutrophil mobilization.
IL-2
- Growth and differentiation of T cells.
- Th0 –> Th1
IL-4
- Basophil development.
- Eosinophil chemotaxis.
- Cell fusions in granulomas.
- Fever.
- Down regulates neutrophil superoxide production.
- Th0 –> Th2.
- Monocytes –> dendritic cells (with GMCSF)
IL-6
T cells, endothelial cells.
- Monocyte differentiation.
- Increase platelets.
- Increase fibriniogen.
- Neutrophil mobilization.
- Fever.
IL-10
Macrophages, T cells.
- Inhibits production of pro-inflammatory cytokines.
IL-12
Macrophages, B cells
- Proliferation of NK cells, Th cells and CTLs.
IL-21
Th0 –> Tfh
IL-23
Th0 –> Th17
TNF-alpha, TNF-beta
Macrophages
- See IL-1.
- Apoptosis.
- Activation of macrophages.
TGF-beta
- Suppress hematopoiesis.
- Inhibits neutrophil accumulation.
- Inhibits production of pro-inflammatory cytokines.
- Th0 –> Treg
- Inhibits B cell growth.
- IgA switch factor.
INF-alpha, INF-beta
- Inhibit viral replication.
- Activate NK cells
INF-gamma
T cells, NK cells
- Upregulates MHC proteins.
- Activates macrophages.
