WordNet

small room in which a monk or nun lives (同)cubicle
a device that delivers an electric current as the result of a chemical reaction (同)electric cell
a room where a prisoner is kept (同)jail cell, prison cell
(biology) the basic structural and functional unit of all organisms; they may exist as independent units of life (as in monads) or may form colonies or tissues as in higher plants and animals
any small compartment; "the cells of a honeycomb"
a small unit serving as part of or as the nucleus of a larger political movement (同)cadre
any substance (as a toxin or enzyme) that stimulates an immune response in the body (especially the production of antibodies)

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(刑務所の)『独房』;(修道院の)小さい独居室 / (ミツバチの)みつ房,巣穴 / 小さい部屋 / 『細胞』 / 電池 / 花粉室 / (共産党などの)細胞
抗原(生物の体内にはいって免疫体を作る物質)

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2015/07/27 21:57:26」(JST)

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Antigen presentation stimulates T cells to become either "cytotoxic" CD8+ cells or "helper" CD4+ cells.

An antigen-presenting cell (APC) or accessory cell is a cell that displays foreign antigens complexed with major histocompatibility complexes (MHCs) on their surfaces; this process is known as antigen presentation. T-cells may recognize these complexes using their T-cell receptors (TCRs). These cells process antigens and present them to T-cells.

Types

Antigen-presenting cells fall into two categories: professional and non-professional.

T cells cannot recognize, and therefore cannot respond to, 'free' antigen. T cells can only 'see' an antigen that has been processed and presented by cells via carrier molecules like MHC and CD1 molecules. Most cells in the body can present antigen to CD8⁺ T cells via MHC class I molecules and, thus, act as "APCs"; however, the term is often limited to specialized cells that can prime T cells (i.e., activate a T cell that has not been exposed to antigen, termed a naive T cell). These cells, in general, express MHC class II as well as MHC class I molecules, and can stimulate CD4⁺ ("helper") T cells as well as CD8⁺ ("cytotoxic") T cells, respectively.

To help distinguish between the two types of APCs, those that express MHC class II molecules are often called professional antigen-presenting cells.

Professional

Professional APCs are very efficient at internalizing antigens, either by phagocytosis or by receptor-mediated endocytosis, and then displaying a fragment of the antigen, bound to a class II MHC molecule, on their membrane. The T cell recognizes and interacts with the antigen-class II MHC molecule complex on the membrane of the antigen-presenting cell. An additional co-stimulatory signal is then produced by the antigen-presenting cell, leading to activation of the T cell. The expression of co-stimulatory molecules is a defining feature of professional APCs.

There are three main types of professional antigen-presenting cells:

Dendritic cells (DCs), which have the broadest range of antigen presentation, and are probably the most important APC. Activated DCs are especially potent T_H cell activators because, as part of their composition, they express co-stimulatory molecules such as B7. This B7 co-stimulator of mature interdigitating dendritic cell (IDC) interacts with surface CD28 of naïve T-cell.
Macrophages.
Certain B-cells, which express (as B cell receptor) and secrete a specific antibody, can internalize the antigen, which bind to its BCR and present it incorporated to MHC II molecule, but are inefficient APC for most other antigens.
Certain activated epithelial cells

Non-professional

A non-professional APC does not constitutively express the Major Histocompatibility Complex class II (MHC class II) proteins required for interaction with naive T cells; these are expressed only upon stimulation of the non-professional APC by certain cytokines such as IFN-γ. All nucleated cells express the Major Histocompatibility Complex class I necessary to be considered a non-professional APC. As erythrocytes do not have a nucleus, they are one of the few cells in the body that cannot display antigens.

Interaction with T cells

After APCs have phagocytosed pathogens, they usually migrate to the vast network of lymph vessels and are carried by lymph flow to the draining lymph nodes. Each lymph node is a collection point where APCs such as dendritic cells (DCs) can interact with T cells. They do this by chemotaxis, which involves interacting with chemokines that are expressed on the surface of cells (e.g., endothelial cells of the high endothelial venules) or have been released as chemical messengers to draw the APCs to the lymph nodes. During the migration, DCs undergo a process of maturation: they lose most of their ability to further engulf pathogens and they develop an increased ability to communicate with T cells. Enzymes within the cell digest the swallowed pathogen into smaller pieces containing epitopes, which are then presented to T cells by the MHC.

Recent research indicates that only certain epitopes of a pathogen are presented because they are immunodominant, seemingly as a function of their binding affinity to the MHC. This stronger binding affinity allows the complex to remain kinetically stable long enough to be recognized by T cells.

External links

Antigen: protease degradation on YouTube - PMAP The Proteolysis Map-animation
Antigen-Presenting Cells at the US National Library of Medicine Medical Subject Headings (MeSH)

References

T. J. Kindt and R. A. Goldsby, Kuby immunology, 6th edition, W.H. Freeman, 2007.

UpToDate Contents

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English Journal

Modulation of interferon-γ synthesis by the effects of lignin-like enzymatically polymerized polyphenols on antigen-presenting cell activation and the subsequent cell-to-cell interactions.

Yamanaka D, Motoi M, Ishibashi K, Miura NN, Adachi Y, Ohno N.SourceLaboratory for Immunopharmacology of Microbial Products, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo 192-0392, Japan.
Food chemistry.Food Chem.2013 Dec 15;141(4):4073-80. doi: 10.1016/j.foodchem.2013.06.114. Epub 2013 Jul 4.
Lignin-like polymerized polyphenols strongly activate lymphocytes and induce cytokine synthesis. We aimed to characterise the mechanisms of action of polymerized polyphenols on immunomodulating functions. We compared the reactivity of leukocytes from various organs to that of polymerized polyphenols
PMID 23993587

Active immunotherapy using dendritic cells in the treatment of glioblastoma multiforme.

Bregy A, Wong TM, Shah AH, Goldberg JM, Komotar RJ.SourceUniversity of Miami Miller School of Medicine, Department of Neurological Surgery, Miami, FL, USA.
Cancer treatment reviews.Cancer Treat Rev.2013 Dec;39(8):891-907. doi: 10.1016/j.ctrv.2013.05.007. Epub 2013 Jun 21.
OBJECTIVE: Glioblastoma multiforme, the most common malignant brain tumor still has a dismal prognosis with conventional treatment. Therefore, it is necessary to explore new and/or adjuvant treatment options to improve patient outcomes. Active immunotherapy is a new area of research that may be a su
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Regulation of macrophage and dendritic cell function by pathogens and through immunomodulation in the avian mucosa.

de Geus ED, Vervelde L.SourceDepartment of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 1, 3584 CL Utrecht, The Netherlands. Electronic address: e.d.degeus@uu.nl.
Developmental and comparative immunology.Dev Comp Immunol.2013 Nov;41(3):341-51. doi: 10.1016/j.dci.2013.03.008. Epub 2013 Mar 28.
Macrophages (MPh) and dendritic cells (DC) are members of the mononuclear phagocyte system. In chickens, markers to distinguish MPh from DC are lacking, but whether MPh and DC can be distinguished in humans and mice is under debate, despite the availability of numerous markers. Mucosal MPh and DC ar
PMID 23542704

Japanese Journal

人工抗原提示細胞を用いた抗腫瘍CTLの誘導と抗原の同定

岡村文子,葛島清隆
臨床免疫・アレルギー科 62(6), 645-648, 2014-12
NAID 40020294486

移植と最先端医療(3)同種造血幹細胞移植の発展

田中淳司
東京女子医科大学雑誌 84(3), 87-93, 2014-04-25
… またKIR (Killer Ig-like receptor)リガンドのGVH方向不適合によって誘導されるドナー同種反応性NK細胞は患者白血病細胞を攻撃しGVL効果を発揮すると同時に、患者抗原提示細胞 (antigen-presenting cell, APC)を攻撃しGVHDをも抑制すると考えられる。 …
NAID 110009803926

Therapeutic Vaccines for Hypertension and Dyslipidemia

Nakagami Hironori,Koriyama Hiroshi,Morishita Ryuichi
International Heart Journal 55(2), 96-100, 2014
… Their targets are usually specifi c antigens in cancer cells, allowing activated cytotoxic T cells (CTLs) to attach and remove the antigen-presenting cancer cells. … Because the target antigen itself does not include T cell epitopes, the immunogenic molecule (ie, KLH) provides antigen that supports the activation of T cells. …
NAID 130003392081