Interleukin Function / Function of Interleukin

Interleukins have a variety of functions, but most are involved in directing other immune cells to divide and differentiate. Each interleukin acts on a specific, limited group of cells that express its cognate receptors.

At the early stage of exploring the role of interleukins, leukocytes are involved in mounting immune responses, so interleukins were thought to function only as modulators of immune functions. Although this is an important function of interleukins, it is now known that interleukins also are produced by and interact with a host of cells not involved in immunity and are involved in many other physiological functions.

Interleukin Function Table

The immunological functions of most of the interleukins are known to some degree. The following table can offer you quality informations concerning interleukins (1-38) ligands, receptors, cell source, cell targets, and main function.

Note: Click on one of the interleukin boxes below, and you can quickly get detailed contents about the interleukin molecule.

 IL-1A, IL-1B

Receptor: IL-1R1, IL-1R2 Function
Source: Macrophages, many others Induction of proinflammatory proteins, hematopoiesis, differentiation of TH17 cells
Targets: T cells, fibroblasts, epithelial and endothelial cells

  IL-1RA (antagonist)

Receptor: IL-1R1, IL-1R2 Function
Source: Macrophages, many others Antagonism of IL-1
Targets: T cells, fibroblasts, epithelial and endothelial cells

 IL-2

Receptor: IL-2R Function
Source: CD4+ and CD8+ activated T cells, DCs, NK cells, NKT cells Proliferation of effector T and B cells, development of Treg cells, differentiation and proliferation of NK cells and growth factor for B cells
Targets: CD4+ and CD8+ T cells, NK and B cells

 IL-3

Receptor: IL-3Rα, CSF2RB Function
Source: T cells, macrophages, NK cells, mast cells, eosinophils, stromal cells Hematopoietic growth factor, activation of basophils and eosinophils
Targets: Erythroid progenitors, granulocytemacrophages progenitors, CD341 progenitor cells, basophils, eosinophils

 IL-4

Receptor: IL-4R, IL-2Rγ, IL-13Rα1 Function
Source: TH2 cells, basophils, eosinophils, mast cells, NKT cells, γ/δ T cells Induction of TH2 differentiation, IgE class switch, upregulation of class II MHC expression on B cells, upregulation of CD23 and IL-4R, survival factor for B and T cells, role in tissue adhesion and inflammation
Targets: T and B cells

 IL-5

Receptor: IL-5Rα, CSF2RB Function
Source: TH2 cells, activated eosinophils and mast cells, Tc2 cells, γ/δ T cells, NK and NKT cells Differentiation and function of myeloid cells, increment of chemotactic activity and adhesion capacity on eosinophils, remodeling and wound healing
Targets: Eosinophils, basophils, and mast cells

 IL-6

Receptor: IL-6Rα, gp130 Function
Source: Endothelial cells, fibroblasts, monocytes/macrophages Liver: synthesis of acute phase proteins; leukocytes: trafficking, activation; T cell: differentiation, activation, survival; B cell: differentiation, production of IgG, IgM, IgA hematopoiesis
Targets: Hepatocytes, leukocytes, T cells, B cells, hemopoietic cells

 IL-7

Receptor: IL-7Rα, IL-2Rγ Function
Source: Epithelial cells, keratinocytes, DCs, B cells, and monocytes/macrophages Proliferation of pre-B and pro-B cells (mice), megakaryocytes maturation, VDJ recombinations, naive T-cell survival, synthesis induction of inflammatory mediators in monocytes
Targets: B, T, and NK cells

 IL-8/CXCL8

Receptor: CXCR1, CXCR2 Function
Source: Monocytes, macrophages, neutrophils, lymphocytes, endothelial cells, epithelial cells, fibroblasts, keratinocytes Chemoattractant for neutrophils, NK cells, T cells, basophils, eosinophils; mobilization of hematopoietic stem cells; angiogenesis
Targets: Neutrophils, NK cells, T cells, basophils, eosinophils, endothelial cells

 IL-9

Receptor: IL-9R, IL-2Rγ Function
Source: TH2, TH9, mast cells, and eosinophils T and mast cells growth factor, inhibition of TH1 cytokines, proliferation of CD81 T cells and mast cells, IgE production, chemokine and mucus production in bronchial epithelial cells
Targets: B, T, and mast cells

 IL-10

Receptor: IL-10Rα, IL-10Rβ Function
Source: T cells, B cells, monocytes, macrophages, DCs Immune suppression
Targets: Macrophages, monocytes, T cells, B cells, NK cells, mast cells, DC and granulocytes

 IL-11

Receptor: IL-11Rα, gp130 Function
Source: Stromal cells: fibroblasts, epithelial cells, endothelial cells, vascular smooth muscle cells, synoviocytes, osteoblasts Growth factor for myeloid, erythroid, and megakaryocyte progenitors; bone remodeling; protects epithelial cells and connective tissue; induction of acute-phase protein; inhibition of macrophage activity; promotion of neuronal development
Targets: Myeloid, erythroid, and megakaryocyte progenitors, osteoclasts, epithelial cells, hepatocytes, macrophages, neurons

 IL-12A, IL-12B

Receptor: IL-12Rβ1, IL-12Rβ2 Function
Source: Monocytes, macrophages, neutrophils, microglia, DCs, B cells Induce TH1-cell differentiation and cytotoxicity
Targets: T cells (Th1 cells), NK cells

 IL-13

Receptor: IL-13Rα1, IL-13Rα2, IL-4R Function
Source: T, NKT, and mast cells, basophils, eosinophils Switching to IgG4 and IgE, upregulation of CD23, MHC-II on B cells, induction of CD11b, CD11c, CD18, CD29; CD23, and MHC-II on monocytes, activation of eosinophils and mast cells, recruitment and survival of eosinophils, defense against parasite infections
Targets: B cells, mast cells, epithelial cells, eosinophils, smooth muscle cells and macrophages

 IL-14/TXLNA

Receptor: ? Function
Source: T cells, T-cell clones, B-lineage and T-lineage lymphoma cell lines Proliferation of activated B cells
Targets: B cells, certain leukemia cells

 IL-15

Receptor: IL-15Rα, IL-2Rβ, IL-2Rγ Function
Source: Monocytes, activated CD4+ T cells, keratinocytes, skeletal muscle cells T-cell activation, proliferation and activation of NK cells, differentiation of γ/δ T cells, suppression of IL-2 induced AICD of T cells, homeostasis of CD8+ memory, NK and NKT cells, enhancement of TH2 differentiation and suppression of allergic rhinitis
Targets: T, NK, and NKT cells

 IL-16

Receptor: CD4, Function
Source: T cells, eosinophils, mast cells, eosinophils, monocytes, DCs, fibroblasts, epithelial cells Chemotaxis, modulation of T-cell response
Targets: T cells, monocytes, macrophages, eosinophils

 IL-17A

Receptor: IL-17RA, IL-17RC, IL-17RD Function
Source: TH17 cells, CD8+T cells, NK cells, NKT cells, γδ T cells, neutrophils Induction of proinflammatory cytokines, chemokines, and metalloproteases; recruitment of neutrophils
Targets: Epithelial/endothelial cells, fibroblasts, osteoblasts, monocytes, macrophages

 IL-17B

Receptor: IL-17RB Function
Source: neuronal cells, chondrocytes chondrogenesis and osteogenesis
Targets: Monocytes, endothelial cells, myofibroblasts

 IL-17C

Receptor: IL-17RA, IL-17RE Function
Source: immune cells under certain conditions Induction of proinflammatory cytokines, chemokines, and metalloproteases
Targets: Monocytes, endothelial cells, myofibroblasts

 IL-17D

Receptor: ? Function
Source: resting B and T cells Induction of proinflammatory cytokines, chemokines, and metalloproteases
Targets: Monocytes, endothelial cells, myofibroblasts

 IL-17F

Receptor: IL-17RA, IL-17RC Function
Source: TH17 cells, CD8+ T cells, NK cells, NKT cells, γδ T cells, neutrophils Induction of proinflammatory cytokines, chemokines, and metalloproteases; recruitment of neutrophils
Targets: Epithelial/endothelial cells, fibroblasts, osteoblasts, monocytes, macrophages

 IL-18

Receptor: IL-18Rα, IL-18RAcP, IL18BP Function
Source: Wide range of cells, mainly macrophages, Kupffer cells, keratinocytes, osteoblasts, astrocytes, DCs Induction of IFN-γ in presence of IL-12, enhances NK cell cytotoxicity, promoting TH1 or TH2–cell responses depending cytokine milieu
Targets: Variety of cells, T cells, NK cells, macrophages, epithelial cells, chondrocytes

 IL-19

Receptor: IL-20Rα, IL-20Rβ Function
Source: Monocytes, keratinocytes, airway epithelial cells and B cells Inflammatory response
Targets: Keratinocytes

 IL-20

Receptor: IL-20Rα, IL-20Rβ, IL-22Rα1 Function
Source: Monocytes, keratinocytes, epithelial and endothelial cells Role in skin biology
Targets: Keratinocytes, monocytes

 IL-21

Receptor: IL-21R, IL-2Rγ Function
Source: T cells (predominantlyTH17), NKT cells Regulation of proliferation, differentiation, apoptosis, antibody isotype balance, cytotoxic activity
Targets: CD4+ T cells, CD8+ T cells, B cells, DCs, macrophages, keratinocytes

 IL-22

Receptor: IL-22Rα1, IL-22Rα2, IL-10Rβ Function
Source: Activated T cells (predominantly TH17), NKT cells (NK-22) Pathogen defense, wound healing, tissue reorganization
Targets: Tissue cells like keratinocytes, subepithelial myofibroblasts

 IL-23

Receptor: IL-12Rβ1, IL-23R Function
Source: Macrophages, activated DCs Stimulate production of proinflammatory IL-17 and promote memory T-cell proliferation
Targets: T cells (TH17 cells) and macrophages

 IL-24

Receptor: IL-20Rα, IL-20Rβ, IL-22Rα1 Function
Source: Melanocytes, T cells, monocytes Tumor suppression
Targets: Cancer cells

 IL-25/IL-17E

Receptor: IL-17RA, IL-17RB Function
Source: TH2 cells, mast and epithelial cells, eosinophils and basophils from atopic individuals Induction of TH2 responses, IgE, IgG1, IL-4, IL-5, IL-13, and IL-9 production
Targets: TH2 memory cells

 IL-26

Receptor: IL-10Rβ, IL-20Rα Function
Source: Activated T cells (predominantly TH17), NKT cells Activation and regulation of epithelial cells
Targets: Epithelial cells

 IL-27

Receptor: IL-27Rα, gp130 Function
Source: Activated DCs, macrophages, epithelial cells Induction of Tbet promoting TH1-cell differentiation, inhibition of TH17-cell response via STAT1
Targets: T cells, NK cells

 IL-28A, IL-28B

Receptor: IL-28RA, IL-10Rβ Function
Source: Monocyte-derived DCs Antiviral immunity
Targets: Most cell types

 IL-29

Receptor: IL-28RA, IL-10Rβ Function
Source: Monocyte-derived DCs Antiviral immunity
Targets: Most cell types

 IL-31

Receptor: IL-31Rα, OSMR Function
Source: Activated CD41 T cells (mainly TH2) and CD81 T cells Induction of IL-6, IL-8, CXCL1, CXCL8, CCL2, and CCL8 production in eosinophils, upregulates chemokine mRNA expression in keratinocytes, expression of growth factors and chemokines in epithelial cells
Targets: Keratinocytes, epithelial cells, monocytes, eosinophils, basophils

 IL-32

Receptor: PR3, PKCε, PKCδ, STAT3, Paxillin Function
Source: Monocytes, macrophages, NK cells, T cells, epithelial cells Induction of TNF-a, IL-8, and IL-6, apoptosis
Targets: Macrophages, DCs, T cells, PBMCs, monocytes

 IL-33

Receptor: IL-1RL1, IL-1RAcP Function
Source: Necrotic cells and nuocytes Transcriptional repressor activity, induction of TH2 inflammation on mucosal tissues
Targets: Basophils, mast cells, eosinophils, NK cells, NKT cells, TH2 cells, DCs, nuocytes

 IL-34

Receptor: CSF-1R Function
Source: Heart, brain, liver, kidney, spleen, thymus, testes, ovary, small intestine, prostate, colon, most abundant in spleen Proliferation
Targets: Monocytes, macrophages

 IL-35 (p35+EBI3)

Receptor: IL-12Rβ2, gp130 Function
Source: Treg cells Proliferation of Treg cells and inhibition of TH17-cell function, suppression of inflammatory responses
Targets: Different T-cell subsets

 IL-36A, IL-36B, IL-36G, IL-36RA

Receptor: IL-1RL2, IL-1RAcP Function
Source: Monocytes, T/B-lymphocytes, spleen, heart, lung, testis, colon, neuron cells Regulation of dendritic and activated Th1 cell response in skin inflammation
Targets: CD4+ T cells

 IL-37

Receptor: IL18R1 Function
Source: Monocytes, tonsil plasma cells, breast carcinoma cells Suppression of proinflammatory cytokines and inhibition of DC activation
Targets: Intracellular mechanism manner and DC

 IL-38

Receptor: IL-1R1, IL1RL2 Function
Source: Basal epithelia of skin, spleen, fetal liver, placenta, and thymus and proliferating B cells of the tonsils Inhibition of the prodution of TH17 response cytokines; antagonism of IL-36
Targets: ?

References

1. SnapShot: Cytokines I Cristina M. Tato and Daniel J. Cell 132, p. 324
2. Akdis, M., Burgler, S., Crameri, R., Eiwegger, T., Fujita, H., Gomez, E., ... & Rhyner, C. (2011). Interleukins, from 1 to 37, and interferon-γ: receptors, functions, and roles in diseases. Journal of allergy and clinical immunology, 127(3), 701-721.