Interleukins: Functions and Types

Posted on Feb 9, 2025 in Biology

  • IL-1: Produced by macrophages and epithelial cells, it induces an acute phase response and activation and recognition by T cells and macrophages where the immune response develops. It works with TNF in innate immunity and inflammation.
  • IL-2: Produced by Th1 cells, it stimulates the growth and differentiation of the T-lymphocyte response.
  • IL-3: Produced by Th2 lymphocytes, it stimulates stem cells from bone marrow.
  • IL-4: Related to the proliferation of B cells, mast cells, and T lymphocytes. It has an important role in allergic reactions.
  • IL-5: Produced by T lymphocytes and mast cells, it stimulates the growth and proliferation of eosinophils.
  • IL-6: Secreted by macrophages, it is involved in acute phase reactions. It also stimulates the growth and differentiation of both T cells and B cells.
  • IL-7: PM 25000 glycoproteins secreted by stromal cells of the thymus, spleen, and bone marrow, which functions as a growth factor for both T cell precursors and B cells.
  • IL-8: Produced by monocytes, macrophages, keratinocytes, fibroblasts, and endothelial cells. Its function is to attract neutrophils and virgin lymphocytes, and to mobilize, activate, and induce neutrophil degranulation. It also stimulates angiogenesis.
  • IL-9: A lymphokine, importantly a glycosylated polypeptide with an MW of 30,000 to 40,000. Secreted by activated T cells by IL-2, and *in vitro* effects of growth promoters on mast cells. It can also co-stimulate T cells with IL-2 or IL-4 and may encourage the potential of hematopoietic progenitors.
  • IL-10: (Formerly cytokine synthesis inhibitory factor) with a PM of 18,000 protein produced by TH2 cells, CD8 T cells, monocytes, keratinocytes, and activated B cells. Inhibitor of activated macrophages and dendritic cells; therefore, it participates in the control of innate immune responses and cellular immunity and expression of MHC class II molecules.
  • IL-12: (Called cytotoxic lymphocyte maturation factor or NK cell stimulatory factor) Synthesized predominantly by macrophages and B cells. The production of IL-12 by activated macrophages is suppressed by IL-4 and IL-10. It promotes the proliferation of T cells and activated NK cells, increasing the latter cell’s lytic activity. It is a potent inducer of IFN-gamma production (interferon-gamma) by T and NK cells at rest or activated. It selectively induces the differentiation of TH0 into TH1 cells but suppresses the TH2-dependent functions such as the production of IL-4, IL-10, and IgE antibodies. Production of GM-CSF.
  • IL-13: Produced by CD4 (TH2), NK, and mast cells. Isotype switching to IgE in B lymphocytes, increases mucus production in epithelial cells and collagen synthesis of fibroblasts and macrophages.
  • IL-14: Mediator between plasma cells and the cytoplasm.
  • IL-15: Mediation of growth of T cells (CD8+ memory), proliferation of NK cells.
  • IL-16: Cytokine derived from T cells that act as a specific eosinophil chemoattractant.
  • IL-17: Produced by T lymphocytes, increased chemokine synthesis in endothelial cells and macrophage cells. Summary of GM-CSF and G-CSF.
  • IL-18: Produced by NK cells and T cells, synthesis of IFN-gamma.
  • IL-23: Produced by macrophages and dendritic cells, maintained T cells IL-17 producers.
  • IL-27: Produced by macrophages and dendritic cells, inhibits TH1 cells. Synthesis of IFN-gamma in NK cells.