Interleukin-2 (IL2) is an interleukin, a type of biological response modifier that can improve the body's natural response to disease. It binds to IL2 receptors. Interleukins are a group of cytokines that are expressed by white blood cells (leukocytes, hence the -leukin) as a means of communication (inter-). The function of the immune system depends in a large part on interleukins, and rare deficiencies of a number of them have been described, all featuring autoimmune...

Physiology

IL2 is normally produced by the body, and upon antigen binding it is secreted by T cells. IL2 stimulates growth and differentiation of T-cell response. Administration of IL-2 to humans results in expansion of lymphoid cells and thus is sometimes used in immunotherapy to treat cancer. It enhances the ability of the immune system to kill tumor cells and may interfere with blood flow to the tumor (PMID 9384490). Nevertheless its clinical aplication is limited by its cytotoxicity. T cells are a subset of lymphocytes that play a large role in the immune response. ... Cell-mediated immunity is an immune response that does not involve antibodies but rather involves the activation of macrophages and natural killer cells, the production of antigen-specific cytotoxic T-lymphocytes, and the release of various cytokines in response to an antigen. ... Immunotherapy is a form of medical treatment based upon the concept of modulating the immune system to achieve a therapeutic goal. ... When normal cells are damaged beyond repair, they are eliminated by apoptosis. ... The immune system is the system of specialized cells and organs that protect an organism from outside biological influences. ... Cytotoxicity is the quality of being poisonous to cells. ...

IL2 is necessary in the activation of T cells. When a CD4⁺ T cell binds to a APC using CD28 and B7, the T cell starts to produce IL2. IL2 is needed in the activation of both CD4⁺ and CD8⁺ T-cells. T cells are a subset of lymphocytes that play a large role in the immune response. ... An antigen presenting cell (APC) is a cell that displays foreign antigen complexed with MHC on its surface. ... A T helper cell (sometimes also known as effector T cells or TH cells) are a group of lymphocytes (a type of white blood cell or leukocyte) that play a cornerstone role in establishing and maximising the ability of the immune system. ... A cytotoxic (or TC) T cell is a T cell (a type of white blood cell) which has on its surface antigen receptors that can bind to fragments of antigens displayed by the Class I MHC molecules of virus (or other intracellular pathogen) infected somatic cells and tumor cells. ...

IL-2 as a double-edged sword

Because of the above role of IL-2 in lymphoid proliferation, it was anticipated that phenotype of mice lacking IL-2 would show forms of immunodeficiency. Instead the mice produce broad range of autoantibodies and many die of autoimmune heamolytic anaemia. Therefore, the role of IL-2 is not only to induce lymphoid growth, but also to maintain peripheral tolerance by means of regulatory T cells, which are absent in IL-2 knock-out mice (see also Foxp3; CD25). The phenotype of an individual organism is either its total physical appearance and constitution or a specific manifestation of a trait, such as size or eye color, that varies between individuals. ... In medicine, immune deficiency (or immunodeficiency) is a state where the immune system is incapable of defending the organism from infectious disease. ... Regulatory T cells (also known as suppressor T cells) are a specialized subpopulation of T cells that act to suppress activation of the immune system and thereby maintain immune system homeostasis and tolerance to self. ... Foxp3 is a member of the forkhead/winged-helix family of transcriptional regulators and functions as the master regulator in the development and function of regulatory T cells. ...

Pharmacology

The immunosupressing drug Aldesleukin (Proleukin®, ATC code L03AC01) is recombinant IL2 used in treating malignant melanoma and renal cell carcinoma. IL-2 administration is often associated with a variety of autoimmune disorders, including immune thyroiditis and rheumatoid arthritis. The Anatomical Therapeutic Chemical Classification System is used for the classification of drugs. ... Recombinant proteins are proteins that are produced by different genetically modified organisms following insertion of the relevant DNA into their genome. ... Melanoma is a malignant tumor of melanocytes. ... Renal cell carcinoma, also known by the eponym Grawitz tumor, is the most common form of kidney cancer arising from the renal tubule. ... Autoimmune diseases arise from an overactive immune response of the body against substances and tissues normally present in the body. ... Rheumatoid arthritis (RA) is a chronic, inflammatory autoimmune disorder that causes the immune system to attack the joints. ...

Cyclosporine, tacrolimus, and sirolimus either inhibit production or block action of IL2, and are used as immunosuppressive agents in organ transplant patients, as well as in some autoimmune diseases. Cyclosporine, Ciclosporin (INN), or cyclosporin (former BAN), is an immunosuppressant drug. ... Tacrolimus (also FK-506 or Fujimycin) is a 23-membered macrolide lactone discovered in 1984 from the fermentation broth of a Japanese soil sample that contained the fungus Streptomyces tsukubaensis. ... Sirolimus is a relatively new immunosuppressant drug used to prevent rejection in organ transplantation, and is especially useful in kidney transplants. ... An organ transplant is the transplantation of a whole or partial organ from one body to another (or from a donor site on the patients own body), for the purpose of replacing the recipients damaged or failing organ with a working one from the donor site. ... Autoimmune diseases arise from an overactive immune response of the body against substances and tissues normally present in the body. ...

External link

• Proleukin website