Interleukin 4
Encyclopedia
Interleukin-4, abbreviated IL-4, is a cytokine
Cytokine
Cytokines are small cell-signaling protein molecules that are secreted by the glial cells of the nervous system and by numerous cells of the immune system and are a category of signaling molecules used extensively in intercellular communication...

 that induces differentiation of naive helper T cells (Th0 cells) to Th2 cells. Upon activation by IL-4, Th2 cells subsequently produce additional IL-4. The cell that initially produces IL-4, thus inducing Th0 differentiation, has not been identified, but recent studies suggest that basophils may be the effector cell. It is closely related and has functions similar to Interleukin 13
Interleukin 13
Interleukin 13 is a protein that in humans is encoded by the IL13 gene. IL-13 is cytokine secreted by many cell types, but especially T helper type 2 cells, that is a mediator of allergic inflammation and disease.-Functions:...

.

Its receptor is the Interleukin-4 receptor
Interleukin-4 receptor
Interleukin 4 receptor is a type I cytokine receptor. IL4R is its human gene.-Interactions:Interleukin-4 receptor has been shown to interact with SHC1.-Further reading:-External links:...

.

Functions

It has many biological roles, including the stimulation of activated B-cell and T-cell proliferation
Cell growth
The term cell growth is used in the contexts of cell development and cell division . When used in the context of cell division, it refers to growth of cell populations, where one cell grows and divides to produce two "daughter cells"...

, and the differentiation of CD4
CD4
CD4 is a glycoprotein expressed on the surface of T helper cells, monocytes, macrophages, and dendritic cells. It was discovered in the late 1970s and was originally known as leu-3 and T4 before being named CD4 in 1984...

+ T-cells into Th2 cells.

It is a key regulator in humoral
Humoral immunity
The Humoral Immune Response is the aspect of immunity that is mediated by secreted antibodies produced in the cells of the B lymphocyte lineage . B Cells transform into plasma cells which secrete antibodies...

 and adaptive immunity.

IL-4 induces B-cell class switching to IgE
IGE
IGE was one of the largest services company buying and selling virtual currencies and accounts for MMORPG. During its peak time, it had offices in Los Angeles, China , and headquarters & customer service centre in Hong Kong. IGE was one of the main monopoly in virtual economy services, also known...

, and up-regulates MHC class II
MHC class II
MHC Class II molecules are found only on a few specialized cell types, including macrophages, dendritic cells and B cells, all of which are professional antigen-presenting cells ....

 production. It also induces B cell class switching to IgG4.

IL-4 decreases the production of Th1 cells, macrophages, IFN-gamma, and dendritic cell IL-12.

Overproduction of IL-4 is associated with allergies.

In inflammation and wound repair

Tissue macrophages play an important role in chronic inflammation
Inflammation
Inflammation is part of the complex biological response of vascular tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. Inflammation is a protective attempt by the organism to remove the injurious stimuli and to initiate the healing process...

 and wound repair. The presence of IL-4 in extravascular tissues promotes alternative activation of macrophages into M2 cells and inhibits classical activation of macrophages into M1 cells. An increase in repair macrophages (M2) is coupled with secretion of IL-10
Interleukin 10
Interleukin-10 , also known as human cytokine synthesis inhibitory factor , is an anti-inflammatory cytokine. In humans IL-10 is encoded by the IL10 gene....

 and TGF-β that result in a diminution of pathological inflammation. Release of arginase
Arginase
Arginase is a manganese-containing enzyme. The reaction catalyzed by this enzyme is: arginine + H2O → ornithine + urea. It is the final enzyme of the urea cycle.- Structure and function :Arginase belong to the ureohydrolase family of enzymes....

, proline
Proline
Proline is an α-amino acid, one of the twenty DNA-encoded amino acids. Its codons are CCU, CCC, CCA, and CCG. It is not an essential amino acid, which means that the human body can synthesize it. It is unique among the 20 protein-forming amino acids in that the α-amino group is secondary...

, polyaminases and TGF-β by the activated M2 cell is tied with wound repair and fibrosis
Fibrosis
Fibrosis is the formation of excess fibrous connective tissue in an organ or tissue in a reparative or reactive process. This is as opposed to formation of fibrous tissue as a normal constituent of an organ or tissue...

.

Clinical significance

IL-4 also has been shown to drive mitogenesis, dedifferentiation
Cellular differentiation
In developmental biology, cellular differentiation is the process by which a less specialized cell becomes a more specialized cell type. Differentiation occurs numerous times during the development of a multicellular organism as the organism changes from a simple zygote to a complex system of...

, and metastasis
Metastasis
Metastasis, or metastatic disease , is the spread of a disease from one organ or part to another non-adjacent organ or part. It was previously thought that only malignant tumor cells and infections have the capacity to metastasize; however, this is being reconsidered due to new research...

 in rhabdomyosarcoma
Rhabdomyosarcoma
A rhabdomyosarcoma is a type of cancer, specifically a sarcoma , in which the cancer cells are thought to arise from skeletal muscle progenitors. It can also be found attached to muscle tissue, wrapped around intestines, or in any anatomic location...

.

History

This cytokine was co-discovered by Maureen Howard and William Paul and by Dr. Ellen Vitetta
Ellen Vitetta
Ellen Vitetta is the director of the Cancer Immunobiology Center at the University of Texas Southwestern Medical Center in Dallas.Vitetta is an immunologist who does translational research. She and her colleagues first described IgD on the surface of murine B cells and she was the co-discoverer...

 and her research group in 1982.

The nucleotide
Nucleotide
Nucleotides are molecules that, when joined together, make up the structural units of RNA and DNA. In addition, nucleotides participate in cellular signaling , and are incorporated into important cofactors of enzymatic reactions...

 sequence for human IL-4 was isolated four years later confirming its similarity to a mouse protein called B-cell stimulatory factor-1 (BCSF-1).

External links

  • Interleukin-4 from Gentaur at Gentaur
  • Recombinant Human Interleukin-4 from Cornell University
    Cornell University
    Cornell University is an Ivy League university located in Ithaca, New York, United States. It is a private land-grant university, receiving annual funding from the State of New York for certain educational missions...

  • Interleukin-4 from Allergy Glossary at Health On the Net Foundation
    Health On the Net Foundation
    Health On the Net Foundation is a not-for-profit organization founded in 1995 under the auspices of the Geneva Ministry of Health and based in Geneva, Switzerland. This came about following the gathering of 60 of the world's foremost experts on telemedicine to discuss the growing concerns over the...

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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