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* Interlukin- 6
  ruthur - 09/09/18 09:10
  A friend of mine sit for his exam recently told me he got alot of questions about cytokine and 2 questions about interleukin 6 . Any came across a problem where interleukin 6 is the tie breaker?

No enough info in first aid about IL-6 ..
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* Re:Interlukin- 6
  sujan1992 - 09/09/18 11:12
  i also heard there were questions about il6 related to il6 mediated signaling betwn osteocyte and osteoclast and macrophage secretion during PAMP-TLR association.
anybody found qsn based on it?
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* Re:Interlukin- 6
  goodman - 09/12/18 13:12
  Cytokines and Interferons
IL-2 is secreted by cytotoxic (CD8) and helper (CD4) T lymphocytes, and helps to stimulate T cell response.

The principal source of IL-3 is activated T cells.

IL-3 promotes the growth of hematopoietic progenitors within the bone marrow. This is most similar to the effects of GM-CSF.

IL-4: is secreted by:
• CD4+ Th2 cells
• Macrophages
• Mast cells

IL-4 performs the following functions:
• Inducing IgG/IgE synthesis (most notably)
• Promoting B cell proliferation
• inhibiting Th1 while promoting Th2 proliferation
• Activating M2 macrophages

IL-5: is secreted by:
• Th2 cells
• Mast cells
• Eosinophils

IL-5 performs the following functions:
• IgA production (most notably)
• Differentiation of B cells
• Eosinophil production

IL-8: is secreted by:
• Macrophages
• Lymphocytes
• Endothelial cells

IL-8 functions in neutrophil chemotaxis.
Mnemonic: “Clean up on aisle 8.” Neutrophils are recruited by IL-8 to clear infections.

IL-10 is secreted by:
• Th2 cells
• Mast cells
• Macrophages
• Regulatory T cells (Treg cells)

IL-10 serves to inhibit cytokine production by Th1 cells and serves to suppress the inflammation response.
Mnemonic: TGF-β and IL-10 both attenuate the immune response.

The main source of IL-12 is macrophages.

IL-12 acts to activate NK cells and Th1 cells.

IL-12 promotes differentiation of naive T cells into Th1 cells. Th1 cells, in turn, secrete IFN-γ, which activates macrophages. This positive feedback loop contributes to the development of granulomatous inflammation.

Interferons (IFNs) are a subclass of cytokines, that provide the first line of defense against viral infections, parasitic invasions and tumor cells. There are two main types of IFNs that can be classified based on their cell of origin.

IFN-α and IFN-β (Type I Interferons) is produced by virally infected cells.

The presence of viral dsRNA stimulates Type I IFN production.

Type I IFNs stimulate the cytotoxic activity of lymphocytes, NK cells, and macrophages.

IFN-γ is secreted by:
• Th1 cells
• Cytotoxic T cells
• Dendritic cells
• NK cells

IFN-γ performs the following functions:
• Activates macrophages and NK cells
• Stimulates MHC I and II expression
• Inhibits IL-4-dependent IgE synthesis
• Promotes Th1 lineage
• Inhibits Th2 lineage

IFN-γ activates NK cells as well as macrophages, thereby increasing the presentation of antigens to T cells.

IFN-γ inhibits IL-4-dependent IgE synthesis in humans.

IFN-γ stimulates cell surface expression of MHC (I and II) and presentation of antigens in all cells.

IFN-γ has less antiviral activity than Class I IFNs, but more potent immunoregulatory effects.

Macrophages are the primary source of TNF-α.

TNF-α performs the following functions:
• Mediate septic shock
• Causes vascular leakage
• Induces leukocyte recruitment
• Helps form and maintain granulomas

Hot T-bone stEAK”:
IL-1: fever (hot).
IL-2: stimulates T cells.
IL-3: stimulates bone marrow.
IL-4: stimulates IgE production.
IL-5: stimulates IgA production.
IL-6: stimulates aKute-phase protein production.

The major sources of IL-6 are macrophages and T cells.

IL-6 performs the following functions:
• Induces the production of acute phase reactants (e.g., CRP) by the liver (most notably)
• Stimulates differentiation of B cells into plasma cells
• Promotes antibody secretion
• Acts as a potent pyrogen

IL-1 (osteoclast activating factor) is secreted by:
• Macrophages (most notably)
• B cells
• Monocytes
• Osteoblasts

IL-1 performs the following functions:
• Endogenous pyrogen (most notably induces fever)
• Stimulates T helper cells
• Induces B cells to multiply
• Stimulates acute inflammation
• Activates endothelial adhesion molecules
• Activates osteoclasts (increased bone resorption)

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