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Cancer immunotherapy is the use of the immune system to treat cancer. Immunotherapies are often categorized as active, passive, or combinatory (active and passive). These immunotherapeutic approaches exploit the fact that cancer cells often have subtly different molecules on their surface that can be detected by the immune system known as cancer antigens; cancer antigens are often proteins or other macromolecules (e.g. carbohydrates). Active immunotherapy is used to provoke the immune system into attacking the tumor cells by targeting tumour-associated antigens (TAAs). Passive immunotherapies are intrinsically functional and include monoclonal antibodies, lymphocytes, and cytokines. Among these, antibody therapies are the most successful to date and treat a wide range of cancers. Antibodies are proteins produced by the immune system that bind to a target antigen on the cell surface. In normal physiology the immune system uses them to fight pathogens. Each antibody is specific to one or a few proteins. Those that bind to cancer antigens are used to treat cancer. Cell surface receptors are common targets for antibody therapies and include the CD20, CD274, and CD279. Once bound to a cancer antigen, antibodies can induce antibody-dependent cell-mediated cytotoxicity, activate the complement system, or prevent a receptor from interacting with its ligand, all of which can lead to cell death. Multiple antibodies are approved to treat cancer, including Alemtuzumab, Ipilimumab, Nivolumab, Ofatumumab, and Rituximab. Active cellular therapies usually involve the removal of immune cells from the blood or from a tumor. Immune cells specific for the tumor are activated, cultured and returned to the patient where the immune cells attack the cancer. Cell types that can be used in this way are natural killer cells, lymphokine-activated killer cells, cytotoxic T cells and dendritic cells. The only cell-based therapy approved in the US is Dendreon's Provenge, for the treatment of prostate cancer. Interleukin-2 and interferon-α are cytokines, proteins that regulate and coordinate the behaviour of the immune system. They have the ability to enhance anti-tumor activity and thus can be used as passive cancer treatments. Interferon-α is used in the treatment of hairy-cell leukaemia, AIDS-related Kaposi's sarcoma, follicular lymphoma, chronic myeloid leukaemia and malignant melanoma. Interleukin-2 is used in the treatment of malignant melanoma and renal cell carcinoma. ==History== Cancer immunotherapy arose from advances in oncology and immunology. Immunotherapy began in 1796 when Edward Jenner produced the first vaccine involving immunisation with cowpox to prevent smallpox. Towards the end of the 19th century Emil von Behring and Shibasaburō Kitasato discovered that injecting animals with diphtheria toxin produced blood serum with antitoxins to it. Paul Ehrlich's research gave rise to the "magic bullet" concept; using antibodies to specifically target a disease. The production of pure monoclonal antibodies for therapeutic use became available in 1975 when Georges J. F. Köhler and Cesar Milstein produced the hybridoma technology. In 1997 Rituximab, the first antibody treatment for cancer, was approved by the FDA for treatment of follicular lymphoma. Since this approval, 11 other antibodies have been approved for cancer; Alemtuzumab (2001), Ofatumumab (2009), and Ipilimumab (2011). The production of vaccines for cancer came later than the use of monoclonal antibodies. The first cell-based immunotherapy cancer vaccine, Sipuleucel-T, was approved in 2010 for the treatment of prostate cancer. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Cancer immunotherapy」の詳細全文を読む スポンサード リンク
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