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36 Cards in this Set
- Front
- Back
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4 main categories
CHIT |
Chemokines
Interferons Hematopoeitins Tumor Necrosis Factors |
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2 Main Cytokine producers
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Macrophages/Th cells
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What are 3 major effects of Cytokine production?
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-Hematopoeisis
-inflammation -Innate immune response -Addaptive immune response |
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5 attributes
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pleiotropy
redundancy synergy antagonism cascade induction |
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3 ways of acting
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Autocrine
Endocrine Paracrine |
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Best-understood Cytokine Receptor:
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IL-2Receptor
expressed on Tcells after initial Ag activation; must bind IL-2 for proliferation/differentiation |
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What is required for signal transduction and high-affinity binding by IL-2R?
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For signal transduction: only B/y chains
BUT for high affinity: must have alpha too. |
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What are 3 ways of achieving specificity with Cytokine signalling?
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1. Lable - short half life of cytokine.
2. High-affinity receptors are only expressed on activated cells. 3. Paracrine signalling - Cytokines induce effect after close contact and release. |
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what is the main role of Th cells?
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to secrete cytokines, which activate other things.
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What are the two types of Th cells?
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Th1
th2 |
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What cytokines are secreted by Th1 cells?
What do they induce? |
Antiviral, DTH-stimulating, Tc Cell-mediated response.
Il2, IFN Y, TNF-B |
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What cytokines are secreted by Th2 cells?
What does this induce? |
Il-4, all the IL's except IL-2.
Promote a Bcell and humoral response. |
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What is the purpose of IL-4?
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Promotes class switching to IgE. Determines amt of DNA looping for class switching.
Enhances mast cell proliferation. |
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What is the purpose of IFN-y?
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Increases antigen presentation
Increases MHC1 and 2 expression. |
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What is the role of chemokines?
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Leukocyte trafficking
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What is the role of Hematopoietic cytokines, what are 3?
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Control the leukocyte population.
-Il-2 is secreted by activated Tcells; promotes Bcell Ig class switching. -IL-4 promotes class swithcing to IgE -CSF |
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What is the role of Interferons; what are 3?
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Induce an antiviral state, upregulate MHC1 and MHC2
IFN a/G/beta |
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What are two roles of Tumor Necrosis Factor (TNF)?
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-Cytotoxic
-Vasodilation Systemic effect |
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3 Cytokine receptors to know:
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CTLA-4
Fas CD40-L |
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function of CTLA-4:
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Competes with CD28 to bind B7, the co-stim signal for activating Th cells.
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What is the effect of dysfunctional CTLA-4?
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You'll have TOO much activation of Th cells; enlarged lymph nodes and spleen.
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What is the function of Fas and Fasl?
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Induce apoptosis of activated T cells.
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What is the effect of dysfunctional Fas and Fasl?
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not enough death of activated T cells; too many activated ones, lymphadinopathy.
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What is the role of CD40/CD40L?
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Signal 2 in bcell activation/differentiation.
Causes CYtokine receptors to be expressed on the Bcell. This allows Cytokines to signal #3 and tell the bcell how to class switch. |
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What is the effect of dysfunctional CD40/CD40L?
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No class switching
overabundance of IgM |
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2 main components of a cytokine receptor:
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-Ligand bind unit (alpha)
-Signal transducing unit (Beta) |
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What determines whether Leprosy will be lepramotous or tuberculoid?
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The Th1/Th2 balance.. if
more th1 = cell-mediated response more th2 = humoral response |
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Differences betwn Lepramotous and Tuberculoid Leprosy?
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Tuberculoid: mainly cell-mediated response, DTH, clears the bacteria, can recover.
Lepramotous: Humoral response, macrophages try to clear, cartilage/neurodegeneration. LEss chance of recovery |
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What determines whether Th1 or Th2 cells will be the responding cells to an infection?
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The cytokine environment.
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2 ways to inhibit cytokine activity:
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-Bind cytokine receptors w/out activation.
-Bind the cytokine itself. |
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2 Cytokine-related diseases:
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-Bacterial Septic Shock
-Bacterial Toxic Shock |
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What types of bacteria cause SEPTIC shock?
How? |
Gram negatives - the endotoxin stimulates macrophages to produce too much IL-1 and TNF-a cytokines, which induce a state of shock.
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What causes Toxic Shock?
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GRAM POSITIVES - Staph Aureus - Toxic Shock Syndrome.
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How do Superantigens cause tss?
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-Bind a particular Vbeta sequence of the TCR, and also bind MHC2;
This is regardless of TCR Ag specifity. |
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What is a natural cytokine antagonist?
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-Can be produced by enzymatic cleavage of cytokine receptors; they float around and neutralize other cytokines.
-Some are produced with the express role of binding and inhibiting cytokines. |
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2 ways viruses inhibit cytokine action:
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-Mimic cytokines; bind their receptors and prevent the real function.
-Mimic cytokine receptors; bind the real cytokine, and prevent intended functio. |
