Cytokines Flashcards
What are cytokines?
A low molecular weight protein that are regulators of the immune response
How is cytokine production regulated?
- Not usually stored as preformed molecules
- Gene transcriptional activation is transient and most of cytokine mRNA are unstable
How do cytokines act on their target cells?
By binding specific membrane receptors
What is the two structure of cytokine receptors?
- Extracellular domains
- Cytoplasmic tails
What is the extracellular domains of cytokine receptors?
It is the cytokine binding structure
What is the cytoplasmic tails of cytokine receptors?
They are inside the cell and initiate the signalling pathway
What are the four biological activity classifications of cytokines?
- Interferons
- Pro-inflammatory
- Anti-inflammatory
- T helper cytokines
What are interferons?
Cytokines that inhibit virus replication
What are the two cellular source classifications of cytokines?
- Lymphokines
- Monokines
What are lymphokines produced by?
Produced by lymphocytes
What are monokines produced by?
Produced by monocytes/macrophages
What are the short hands IL, IFN, TNF and GM-CSF stand for?
- Interleukins
- Interferons
- Tumor necrosis factors
- Growth factor
What are the short hands for interleukins, interferons, tumor necrosis factors and growth factor
IL, IFN, TNF and GM-CSF
How is cytokine activity regulated?
- Regulated cytokine receptor expression
- Short half lives
- Cytokines and target cells must be in close proximity
What does pleiotropic mean?
When a cytokine acts on different target cells
What does redundant mean?
When multiple cytokines have the same effect
What does antagonistic mean?
When inhibition of one cytokines effects by another
What does synergistic mean?
When there is a cooperative effect of multiple cytokines
What are the 3 major functional categories of cytokines?
- Mediators and regulators of innate immunity
- mediators and regulators of adaptive immunity
- Stimulators of haematopoiesis
What is the role of type I and III IFNs and where are they produced?
Produced by tissue cells and innate immune cells and are essential for anti-viral immunity
What stimulates type I IFNs synthesis?
Viral nuclei acids
What is the only member of type II IFNs?
IFN-γ
What are IFN-γ mainly produced by?
Activated lymphocytes
What is the role of IFN-γ?
Is a phagocyte activating cytokine and upregulates MHC class I and II
