Cytokines 2

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4 main categories CHIT: Chemokines
Interferons
Hematopoeitins
Tumor Necrosis Factors
2 Main Cytokine producers: Macrophages/Th cells
What are 3 major effects of Cytokine production?: -Hematopoeisis
-inflammation
-Innate immune response
-Addaptive immune response
5 attributes: pleiotropy
redundancy
synergy
antagonism
cascade induction
3 ways of acting: Autocrine
Endocrine
Paracrine
Best-understood Cytokine Receptor:: IL-2Receptor

expressed on Tcells after initial Ag activation; must bind IL-2 for proliferation/differentiation
What is required for signal transduction and high-affinity binding by IL-2R?: For signal transduction: only B/y chains

BUT

for high affinity: must have alpha too.
What are 3 ways of achieving specificity with Cytokine signalling?: 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.
what is the main role of Th cells?: to secrete cytokines, which activate other things.
What are the two types of Th cells?: Th1

th2
What cytokines are secreted by Th1 cells? What do they induce?: Antiviral, DTH-stimulating, Tc Cell-mediated response.

Il2, IFN Y, TNF-B
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.
What is the purpose of IL-4?: Promotes class switching to IgE. Determines amt of DNA looping for class switching.

Enhances mast cell proliferation.
What is the purpose of IFN-y?: Increases antigen presentation
Increases MHC1 and 2 expression.
What is the role of chemokines?: Leukocyte trafficking
What is the role of Hematopoietic cytokines, what are 3?: Control the leukocyte population.

-Il-2 is secreted by activated Tcells; promotes Bcell Ig class switching.

-IL-4 promotes class swithcing to IgE

-CSF
What is the role of Interferons; what are 3?: Induce an antiviral state, upregulate MHC1 and MHC2

IFN a/G/beta
What are two roles of Tumor Necrosis Factor (TNF)?: -Cytotoxic
-Vasodilation

Systemic effect
3 Cytokine receptors to know:: CTLA-4

Fas

CD40-L
function of CTLA-4:: Competes with CD28 to bind B7, the co-stim signal for activating Th cells.
What is the effect of dysfunctional CTLA-4?: You'll have TOO much activation of Th cells; enlarged lymph nodes and spleen.
What is the function of Fas and Fasl?: Induce apoptosis of activated T cells.
What is the effect of dysfunctional Fas and Fasl?: not enough death of activated T cells; too many activated ones, lymphadinopathy.
What is the role of CD40/CD40L?: 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.
What is the effect of dysfunctional CD40/CD40L?: No class switching
overabundance of IgM
2 main components of a cytokine receptor:: -Ligand bind unit (alpha)

-Signal transducing unit (Beta)
What determines whether Leprosy will be lepramotous or tuberculoid?: The Th1/Th2 balance.. if
more th1 = cell-mediated response

more th2 = humoral response
Differences betwn Lepramotous and Tuberculoid Leprosy?: Tuberculoid: mainly cell-mediated response, DTH, clears the bacteria, can recover.

Lepramotous: Humoral response, macrophages try to clear, cartilage/neurodegeneration.
LEss chance of recovery
What determines whether Th1 or Th2 cells will be the responding cells to an infection?: The cytokine environment.
2 ways to inhibit cytokine activity:: -Bind cytokine receptors w/out activation.

-Bind the cytokine itself.
2 Cytokine-related diseases:: -Bacterial Septic Shock

-Bacterial Toxic Shock
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.
What causes Toxic Shock?: GRAM POSITIVES - Staph Aureus - Toxic Shock Syndrome.
How do Superantigens cause tss?: -Bind a particular Vbeta sequence of the TCR, and also bind MHC2;

This is regardless of TCR Ag specifity.
What is a natural cytokine antagonist?: -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.
2 ways viruses inhibit cytokine action:: -Mimic cytokines; bind their receptors and prevent the real function.

-Mimic cytokine receptors; bind the real cytokine, and prevent intended functio.

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Number of cards 36