see also:

• chemokines
• autacoids
• fever - the febrile response to infections
• interleukin-6 (IL-6)
• interleukin-1b (IL-1b)
• immunology
• innate immunity
• adaptive immunity

• cytokines are small proteins released by cells which act through binding to cell wall receptors and affect the behaviour of other cells and perhaps the same cell which are particularly important in the immune response but generally excludes growth factors, hormones, adipokines and adipose-derived hormones (produced by adipose tissue) and autacoids
• C-mannosylation via CMT enzyme determines whether a cytokine receptor reaches the cell surface to exert its function
• many cytokines appear to share similar functions
• cytokines include:
  • chemokines - mediate chemotaxis
  • interferons - main initial defence against viruses
  • interleukins - mainly produced by T-helper cells (exceptions include interleukin-6 (IL-6))
    • those with genetically low IL-1 activity have increased LDL, 15% higher risk IHD, and incr. risk AAA
    • cytokines, including TNF19, IL-6, IL-17A21 and IL-17F22, from adipose immune cells regulate local homeostasis and systemic metabolic processes ¹⁾
      • γδ T cells, invariant natural killer T cells and mucosal-associated invariant T cells all of which rhythmically produce IL-17A exhibit elevated expression of “molecular clock” genes
      • IL-17A within adipose tissue plays a regulatory role in fat storage
  • lymphokines - produced by lymphocytes
  • monokines - produced by monocytes
  • colony stimulating factors
  • TNF
• the body produces a wide array of pyrogenic cytokines such as interleukins (IL-1beta, IL-6), interferon, and tumour necrosis factor alpha and perhaps complement factor 5a and platelet-activating factor, are carried to the blood-brain-barrier (BBB) in the blood
• excessive cytokine release may produce a cytokine storm with possible multi-organ failure and death as may occur in some people with infections such as influenza
  • Suppressors of Cytokine Signalling (SOCS) molecules control the flow of chemical messages inside cells and suppress the activity of the cytokines to prevent unwanted inflammation and tissue damage.
    • the protein SOCS4 plays a crucial role in moderating the immune system's response to influenza ²⁾
• it is thought that viruses may stimulate cells to produce virokines that modulate the actions of cytokines, perhaps by blocking their action at cytokine receptors
• the major anti-inflammatory cytokines include:
  • interleukin (IL)-1 receptor antagonist
  • IL-4, interleukin-6 (IL-6), IL-10, IL-11, and IL-13
    • IL-11:
      • a pro-fibrotic and pro-inflammatory cytokine
      • activates signaling molecules such as extracellular signal-regulated kinase (ERK) and mammalian target of rapamycin complex 1 (mTORC1)
      • also activates Janus kinase-signal transducers and activators of transcription-3 (JAK-STAT3) pathways
      • a 2024 study ³⁾ showed that in aging mice, the expression of IL-11 was upregulated in various types of cells and tissues and that the deletion of either the gene coding for IL-11 or the IL-11 receptor's alpha 1 subunit protected the mice against metabolic decline, frailty, and multimorbidity as they aged.
  • IL-17 is important for preventing Candida disease such as oral thrush partly by reducing production of candidalysin as it indirectly sequesters zinc away from the fungus ⁴⁾ - zinc is an important factor that is needed by the fungus to form invasive hyphae and produce candidalysin
  • specific cytokine receptors for IL-1, tumor necrosis factor-alpha, and IL-18 also function as proinflammatory cytokine inhibitors