Chemokines Flashcards
What are the properties of cytokines?
They regulate host defenses against disease and inflammation
Can be sequestered or membrane bound
Regulate other cell’s activities by acting on signalling cascae which will regulate apoptosis, differentiation, growth
Acts on specific receptos
How are IL-2 and IL-15 SIMILAR
They both act on t-cells and induce their growth
True or false
Cytokines are homologous
false
How many families of cytokine receptors are there? State two of them their structure, function and members, features
6
TNF receptor-TNF-R, CD40, fibronectin DD, cystolic domain jelly roll motif, pro-inflammatory
chemokine receptor-7TM, IL8, chemotactic, triple stranded and b-sheets
Interaction between cytokines, what does it depend on?
It depends on the type of infection. If it’s viral then TH1 will be activated, if it’s extracellular infection then TH2 will be activated
How do TH1 and TH2 regulate each other? How do they work with each other
By releasing the activators they suppress the activity of the other TH activator.
Using transcription factors can adapt to the other TH and work with it, ifn it’s in the corresponding environment
What cytokines are produced when TH1 is activated? What cytokines activate it?
What inhibits it?
When is TH1 activated?
WHat is an example of transcription factors?
IL-12, CD28
IFN, Il-2
IL-10,IL4
Inflammation . or organ specific immunity, viral infection, T-BET,NFK-B
What cytokines are produced when TH2 is activated? What cytokines activate it?
What inhibits it?
IL-4 IL4,5,9,10,13 IFN-G GATA-3 Humoural immunity,allergy
How does cancer mediate and suppress immune response?
By expressing fas ligand, granzymes, perforin which will kill t-cells
creates a tolergenic environment by releasing tgf-b and activating myeloid suppressor cells and release chemokines that repel the t-cells from the environment
Give examples of cytokines that are always released?
g-csf,m-csf, il-6
Give examples of cytokines that are always presynthesized and stored in granules?
tgf-b
Give examples of cytokines that are always stored in membranes?
tnf-a,tgf-a
cytokines complexed in cell surface or ECM?
TGF-B, IL-8
How are cytokines regulated?
By enzymes processing their precursor forms
How do IL-8 work?
By binding to endothelial cells GAG and homing the leukocyte to the inflammatory site
How do chemokines recruit leukocyteS?
They create a concentration dependent gradient where cytokines are in hugh levels in the ECM near the inflammation site and secreted at low levels in the overlying endothelial cells, the leuocyte bind to the selectin and roll on the tissue where they come into contact with the chemokine on the heparan sulphate and this activates the integrin and this causes it to fully adhere and extravasate into tissue where it can carry out it’s effector functions
They recruit it by creating gradients and pro-inflammatory sites
What cytokine are released during last stages?
interferon gamma, interleukin 1, tumour necrosis factor
What is the role of IL-8 in cancer? What would inhibit these processes
Can promote metastasis and angiognesis.
Platelet factor 4 and IL-10
What are they 5 symptoms of advanced cancers and what are the 3 main cytokines associated with cachexia?
TNF, IL-6, IL-1, IFN gamma
Decreased thirst and loss of appetite, weight loss, hypertension, hypoglycaemia or hyperglycemia, fever
How many families of chemokines are there? What are their characteristics?
4
alpha(CXC) and beta(CC);4cystines
t/f
Chemokine receptors are G protein-coupled proteins that
are expressed on subgroups of leukocytes
T
