Cytokines are signaling proteins that act on receptors and regulate the activation of cell differentiation, especially in the immune system.



Interleukin Secreted by

Targets and effect

Interleukin-1 (IL-1)
Interleukin-2 (IL-2)
Interleukin-3 (IL-3)
Interleukin-4 (IL-4)
Interleukin-5 (IL-5)
Interleukin-6 (IL-6)
Interleukin-7 (IL-7)
Interleukin-8 (IL-8)
Interleukin-11 (IL-11)
Interleukin-24 (IL-24)


Interleukin-29 (IL-29)

  • Dendritic cells
Interleukin-32 (IL-32)

Interleukins secreted by macrophages: IL-1, 6, 8, 12 (and TNF-α)
Interleukins secreted by all T cells: IL-2 and 3
Most important proinflammatory interleukins (endogenous pyrogens and main mediators of sepsis): IL-1 and 6 (and TNF-α)
Most important anti-inflammatory interleukin: IL-10
Promoters of differentiation of T cells to Th2: IL-2 and 4
Class switching interleukins: IL-4 and 5
Acute phase reactant stimulators: IL-6 and 11
Neutrophil chemotactic factor: IL-8 (chemokine)

Hot T-bone stEAK represents the effects of IL-1 through IL-6:
IL-1: promotes (hot) fever
IL-2: stimulates proliferation/differentiation of T cells
IL-3: stimulates proliferation of granulocytes and stem cells in the bone marrow
IL-4: stimulates class switching to IgE
IL-5: stimulates class switching to IgA
IL-6: stimulates the synthesis of aKute phase reactants


Interferons and tumor necrosis factor


Interferon Secreted by Function

Therapeutic use

Interferon alpha (IFN-α)
  • Virus‑infected cells and malignant cells, especially leukocytes
Interferon beta (IFN-β)
Interferon gamma (IFN-γ)
  • Activates macrophages to increase phagocytosis (positive reinforcement)
  • Formation of granulomas (critical against mycobacterial infections)
  • Suppresses a Th2 response (negative feedback)
  • Promotes the expression of MHC class II molecules

Tumor necrosis factor

Secreted by Functions Therapeutic use
Tumor necrosis factor alpha (TNF-α; cachectin)
  • Pyrogenic
  • Cytotoxic and inhibits carcinogenesis of certain tumors
  • Mediates septic shock
  • Cause of malignant cachexia
  • Maintenance of granulomas (critical defense against mycobacterial infections)
  • TNF‑α inhibitors such as infliximab are used in the treatment of refractory chronic inflammatory systemic diseases (e.g., Crohn disease).

Tumor necrosis factor beta (TNF-β; lymphotoxin)

Th1 lymphocytes secrete IFN-γ, which activates macrophages and is essential for the formation of tubercular granulomas.
Activated macrophages secrete TNF-α, which is essential for the maintenance of tubercular granulomas.



Enzyme Intermediate Eicosanoid Function

Clinical relevance

(analogs and inhibitors)

Arachidonic acid
  • Bronchoconstriction
  • Increased capillary permeability

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last updated 01/23/2020
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