II. Definitions
- Antigen
- Molecules recognized by antibodies, or by T Cells (as peptides presented via MHC complex on host cells)
- Possible Antigens include Proteins, Nucleic Acids, lipids, complex Carbohydrates
- Antigens must be macromolecules, large enough to generate an immune response (Immunogens)
- Antigens have one or more Epitopes to which immune agents (e.g. antibodies) bind
- Hapten
- Antigen that is too small on its own to generate an immune response
- When Haptens are attached to macromolecules (immunogens), that may act as Epitopes for immune binding
- Immunogen
- Antigen that is large enough to generate an immune response
- Epitopes (Determinants)
- Antigen regions to which immune agents (e.g. antibodies) bind
- Antigen Processing
- Conversion to peptides of exogenous Antigens (endocytic path) and endogenous Antigens (cytosolic path)
- Peptide form is required for T-Cell recognition
III. Images
IV. Type: Cytosolic Pathway for Endogenous Antigens (MHC Class I Complex)
- Indications
- Endogenous Antigens (e.g. Intracellular Bacteria, intracellular Parasites, viruses)
- Antigen Processing starts within the cell cytosol
- Pathway
- Intracellular Antigens within the cell cytosol are processed by proteolytic enzymes within proteasome
- Processing results in converting Antigens to peptides
- Peptides are moved to endoplasmic reticulum where they are bound to MHC Class I molecules
- Antigen Peptide-MHC Class I Complex is moved to cell surface via golgi complex
- Intracellular Antigens within the cell cytosol are processed by proteolytic enzymes within proteasome
- Antigen Presenting Cells (APC or Host Cells) displaying MHC Class I Complex
- All nucleated host cells (unlike MHC Class II of the Endocytic Pathway)
- Cells with Receptors Recognizing MHC Class I Complex
- CD8+ T-Cells (Cytotoxic T-Cells)
V. Type: Endocytic Pathway for Exogenous Antigens (MHC Class II Complex)
- Indications
- Exogenous Antigens
- Pathway
- Exogenous Antigens are engulfed by cells via Phagocytosis (endocytosis) as Phagosomes (endosomes)
- Cell membrane invaginates around the Antigens, surrounding them in a Vesicle
- Phagosomes fuse with Lysosomes (forming phagolysosomes)
- Proteolytic enzymes within the Lysosome breakdown or process the Antigen into peptides
- Antigenic peptides are bound to MHC Class IIMolecules while still inside the phagolysosome
- Antigen Peptide-MHC Class II Complex is moved to cell surface via secretory Vesicles
- Exogenous Antigens are engulfed by cells via Phagocytosis (endocytosis) as Phagosomes (endosomes)
- Antigen Presenting Cells (APC or Host Cells) displaying MHC Class II Complex
- Langerhans Cells and Dendritic Cells
- Macrophages
- B-Cell (B-Lymphocyte)
- Cells with Receptors Recognizing MHC Class II Complex
- CD4+ T-Cells (T-Helper Cells)
VI. References
- Mahmoudi (2014) Immunology Made Ridiculously Simple, MedMaster, Miami, FL
- Guyton and Hall (2006) Medical Physiology, p. 419-50
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Related Studies
Definition (MSHCZE) | Heterogenní skupina imunokompetentních buněk, která zprostředkovává buněčnou imunitní odpověď organismu zpracováváním a předkládáním antigenů T-buňkám. Tradiční buňky předkládající antigen zahrnují MAKROFÁGY, DENDRITICKÉ BUŇKY, LANGERHANSOVY BUŇKY a B-LYMFOCYTY. DENDRITICKÉ BUŇKY FOLIKULÁRNÍ nejsou tradičními buňkami předkládajícími antigen, ale mají na svém povrchu antigen ve formě imunokomplexu (ANTIGEN-PROTILÁTKA KOMPLEX) tak, aby byl rozpoznán B- buňkami, a proto jsou některými autory považovány za tento typ buněk. |
Definition (NCI_NCI-GLOSS) | A type of immune cell that boosts immune responses by showing antigens on its surface to other cells of the immune system. An antigen-presenting cell is a type of phagocyte. |
Definition (NCI) | A cell that enables a T-lymphocyte to recognize an antigen by engulfing the antigen, breaking down the antigen into smaller fragments which bind to MHC molecules on the surface of the antigen presenting cell. The T-lymphocyte can now recognize and bind with the MHC-linked antigen. |
Definition (CSP) | heterogeneous group of immunocompetent cells that mediates the cellular immune response by processing and presenting antigens to the T-cell receptor; traditional antigen presenting cells include macrophages, dendritic cells, Langerhans cells, and B-lymphocytes; follicular dendritic cells are also considered to be antigen presenting cells by some. |
Definition (MSH) | A heterogeneous group of immunocompetent cells that mediate the cellular immune response by processing and presenting antigens to the T-cells. Traditional antigen-presenting cells include MACROPHAGES; DENDRITIC CELLS; LANGERHANS CELLS; and B-LYMPHOCYTES. FOLLICULAR DENDRITIC CELLS are not traditional antigen-presenting cells, but because they hold antigen on their cell surface in the form of IMMUNE COMPLEXES for B-cell recognition they are considered so by some authors. |
Concepts | Cell (T025) |
MSH | D000938 |
English | Accessory Cell, Immunologic, Accessory Cells, Immunologic, antigen presenting cell, Antigen-Presenting Cell, Antigen-Presenting Cells, Cell, Antigen-Presenting, Cell, Immunologic Accessory, Cells, Antigen-Presenting, Cells, Immunologic Accessory, Immunologic Accessory Cell, Immunologic Accessory Cells, ACCESSORY CELL IMMUNOL, CELL IMMUNOL ACCESSORY, ACCESSORY CELLS IMMUNOL, IMMUNOL ACCESSORY CELL, CELLS IMMUNOL ACCESSORY, IMMUNOL ACCESSORY CELLS, accessory cell, Antigen Processing Cell, antigen-presenting cell (APC), apc, antigen presenting cells, antigen-presenting cells, Dendritic cell, Antigen-presenting cell, Antigen-presenting dendritic cell, Antigen presenting cell, Antigen presenting cells, APC, antigen-presenting cell, Antigen Presenting Cells, Accessory Cell, Antigen Presenting Cell |
French | Cellules accessoires (immunité), Cellules présentatrices d'Ag, CPA (Cellule Présentatrice d'Antigène), Cellules présentatrices de l'antigène, Cellules présentatrices d'antigènes, Cellules accessoires immunitaires, Cellules présentatrices d'antigène, Cellules de présentation des antigènes, Cellule présentatrice d'antigène |
Swedish | Antigenpresenterande celler |
Czech | buňky předkládající antigen, buňky prezentující antigen |
Finnish | Antigeenia esittelevät solut |
Italian | Cellula accessoria immunologica, Cellule accessorie immunologiche, Cellule presentanti l'antigene |
Russian | ANTIGEN-PREZENTIRUIUSHCHIE KLETKI, ANTIGEN-PREDSTAVLIAIUSHCHIE KLETKI, DOBAVOCHNYE KLETKI IMMUNOLOGICHESKIE, АНТИГЕН-ПРЕДСТАВЛЯЮЩИЕ КЛЕТКИ, АНТИГЕН-ПРЕЗЕНТИРУЮЩИЕ КЛЕТКИ, ДОБАВОЧНЫЕ КЛЕТКИ ИММУНОЛОГИЧЕСКИЕ |
Japanese | 抗原提示細胞, 免疫付属細胞, 抗原付与細胞, 免疫提示細胞, 提示細胞-免疫 |
Croatian | STANICE KOJE PREDOČUJU ANTIGEN |
Polish | Komórki prezentujące antygen |
Norwegian | Immunceller, aksessoriske, Antigenpresenterende celler, Aksessoriske immunceller |
German | Akzessorische Zellen, immunologisch, Immunologisch-akzessorische Zellen, Zelle, immunologisch-akzessorische, Antigenpräsentierende Zellen, Zellen, immunologisch-akzessorische |
Dutch | Antigenpresenterende cel, Antigenpresenterende cellen, Cel, antigenpresenterende, Helpercel, Helpercellen, Helpercellen, immunologische, Immunologische helpercellen |
Portuguese | Células Apresentadoras de Antígenos, Células Imunológicas Acessórias |
Spanish | Células Inmunológicas Accesorias, Células Presentadoras de Antígenos |
Ontology: Epitopes (C0003316)
Definition (NCI) | The simplest form of an antigenic determinant, on a complex antigenic molecule, which can combine with antibody or T cell receptor. |
Definition (MSH) | Sites on an antigen that interact with specific antibodies. |
Concepts | Immunologic Factor (T129) |
MSH | D000939 |
SnomedCT | 52078008 |
English | Antigenic Determinants, Determinants, Antigenic, Epitopes, antigenic determinant, Epitopes [Chemical/Ingredient], epitopes, epitope, Antigenic determinants, Antigenic determinant, Epitope, Epitope (substance), Binding Determinants, Antigenic Determinant |
Swedish | Epitoper |
Czech | epitopy, antigenní determinanty |
Finnish | Epitoopit |
Italian | Determinanti antigenici, Epitopi |
Russian | DETERMINANTY ANTIGENNYE, ANTIGENNAIA SPETSIFICHNOST', EPITOPY, ANTIGENNYE DETERMINANTY, АНТИГЕННАЯ СПЕЦИФИЧНОСТЬ, АНТИГЕННЫЕ ДЕТЕРМИНАНТЫ, ДЕТЕРМИНАНТЫ АНТИГЕННЫЕ, ЭПИТОПЫ |
Japanese | 抗原決定基, 抗原決定群, 抗原性決定群, 抗原特異性, エピトープ |
French | Déterminants antigéniques, Épitopes, Sites antigéniques |
Croatian | Not Translated[Epitopes] |
Polish | Determinanty antygenowe, Epitopy |
Spanish | Epítopos, Epítopes, determinante antigénico, epítope (sustancia), epítope, Determinantes Antigénicos |
German | Antigene Determinanten, Epitope |
Portuguese | Determinantes Antigênicos, Epitopos |
Ontology: Antigens (C0003320)
Definition (NCI) | Any substance, generally a protein, that stimulates the immune system and elicits an immune response. Recognition by the immune system elicits either a T-lymphocyte response, recognizing processed antigens, or a B-lymphocyte response, producing antibodies that bind to unprocessed antigens. |
Definition (NCI_NCI-GLOSS) | Any substance that causes the body to make a specific immune response. |
Definition (MSH) | Substances that are recognized by the immune system and induce an immune reaction. |
Definition (PSY) | Substances such as microorganisms or foreign tissues, cells, proteins, toxoids, or exotoxins having the ability to induce antibody formation. |
Definition (CSP) | any substance recognized by the immune system and inducing an immune reaction. |
Concepts | Immunologic Factor (T129) |
MSH | D000941 |
SnomedCT | 7120007 |
LNC | LP20739-6, LP20666-1, LP36615-0, LP30821-0 |
English | Antigen, Antigens, immunogen, Antigens [Chemical/Ingredient], Ag, antigens, antigen, immunogens, ag, Immunogen, Antigen (substance), Antigen, NOS, Immunogen, NOS, Immunogens |
Swedish | Antigener |
Czech | antigeny |
Finnish | Antigeenit |
Russian | ANTIGENY, АНТИГЕНЫ |
Japanese | 抗原 |
French | Antigène, Antigènes |
Croatian | ANTIGENI |
Polish | Antygeny |
Norwegian | Not Translated[Antigens] |
Spanish | antígeno (sustancia), antígeno, Antígenos |
German | Antigene |
Italian | Antigeni |
Portuguese | Antígenos |
Ontology: Haptens (C0018593)
Definition (NCI) | A substance that can act as an epitope for an antibody but that lacks immunogenicity unless coupled to a larger carrier molecule. |
Definition (MSH) | Small antigenic determinants capable of eliciting an immune response only when coupled to a carrier. Haptens bind to antibodies but by themselves cannot elicit an antibody response. |
Definition (CSP) | substances which can act as an epitope for antibody but lack immunogenicity unless coupled to a larger carrier molecule. |
Concepts | Immunologic Factor (T129) |
MSH | D006241 |
SnomedCT | 112124006 |
English | Haptens, incomplete antigen, partial antigen, haptin, proantigens, Haptens [Chemical/Ingredient], haptene, haptens, hapten, Hapten, Haptene, Haptin, Incomplete antigen, Partial antigen, Proantigen, Hapten (substance) |
Swedish | Haptener |
Czech | hapteny |
Finnish | Hapteenit |
Russian | GAPTENY, ГАПТЕНЫ |
Japanese | ハプテン, ハプテン部分抗原, 不完全抗原 |
French | Haptènes |
Croatian | Not Translated[Haptens] |
Polish | Hapteny |
Spanish | antígeno incompleto, antígeno parcial, hapteno (sustancia), hapteno, proantígeno, Haptenos |
German | Haptene |
Italian | Apteni |
Portuguese | Haptenos |
Ontology: Antigen Processing (C0206430)
Definition (NCI) | The process by which foreign molecules are taken up by antigen presenting cells, proteolytically cleaved, and displayed on the cell surface in complex with MHC molecules. |
Concepts | Cell Function (T043) |
MSH | D017951 |
SnomedCT | 40187000 |
English | Antigen Processings, Antigen Processing, Antigen processing, function, Antigen processing, Antigen processing, function (observable entity), Antigen processing (function) |
Czech | antigen - zpracovávání |
Portuguese | Antígeno Processado |
Spanish | Proceso de Anticuerpo, procesamiento antigénico (entidad observable), procesamiento antigénico (función), procesamiento antigénico, procesamiento de un antígeno |
German | Antigenprozessierung |
French | Apprêtement antigénique, Apprêtement des antigènes, Apprêtement de l'antigène, Apprêtement d'antigène |
Italian | Processamento dell'antigene |
Norwegian | Antigenprosessering |
Ontology: Antigen Presentation (C0206431)
Definition (GO) | The process in which an antigen-presenting cell expresses antigen (peptide or lipid) on its cell surface in association with an MHC protein complex. [GO_REF:0000022, GOC:add, GOC:mtg_15nov05, ISBN:0781735149, PMID:15771591, PMID:15928678] |
Definition (NCI) | The event of providing fragments of foreign proteins, including viruses and bacteria, to the helper T cells. The presentation occurs through the display of the fragments of foreign proteins on the surface of the antigen-presenting cells (APC).(HIV Glossary; http://aidsinfo.nih.gov) |
Definition (MSH) | The process by which antigen is presented to lymphocytes in a form they can recognize. This is performed by antigen presenting cells (APCs). Some antigens require processing before they can be recognized. Antigen processing consists of ingestion and partial digestion of the antigen by the APC, followed by presentation of fragments on the cell surface. (From Rosen et al., Dictionary of Immunology, 1989) |
Definition (CSP) | process by which an antigen is presented to lymphocytes in a form they can recognize; antigen presenting cells may ingest or digest the antigen and present the fragments to the cell surface for recognition by the lymphocytes. |
Concepts | Cell Function (T043) |
MSH | D017951 |
English | Antigen Presentations, antigen processing and presentation, antigen processing, Antigen Presentation, antigen presentation |
Swedish | Antigenpresentation |
Czech | antigen - nabízení |
Finnish | Antigeenin esittely |
French | Présentation antigénique, Présentation des antigènes, Présentation de l'antigène, Présentation d'antigène |
Russian | ANTIGENOV PREZENTATSIIA, ANTIGENOV OBRABOTKA, ANTIGENOV PREDSTAVLENIE, АНТИГЕНОВ ОБРАБОТКА, АНТИГЕНОВ ПРЕДСТАВЛЕНИЕ, АНТИГЕНОВ ПРЕЗЕНТАЦИЯ |
Polish | Prezentacja antygenu |
Norwegian | Antigenpresentasjon, Antigenframvisning |
German | Antigenpräsentation |
Italian | Presentazione antigenica |
Dutch | Antigeenpresentatie, Presentatie, antigeen- |
Portuguese | Apresentação do Antígeno |
Spanish | Presentación de Antígeno |
Ontology: antigen processing and presentation of endogenous antigen (C1154990)
Definition (GO) | The process in which an antigen-presenting cell expresses antigen (peptide or lipid) of endogenous origin on its cell surface in association with an MHC protein complex. [GOC:add, ISBN:0781735149, PMID:15771591, PMID:15928678] |
Concepts | Cell Function (T043) |
English | antigen presentation, endogenous antigen, antigen processing and presentation of endogenous antigen |
Ontology: antigen processing and presentation of exogenous antigen (C1154993)
Definition (GO) | The process in which an antigen-presenting cell expresses antigen (peptide or lipid) of exogenous origin on its cell surface in association with an MHC protein complex. [GOC:add, ISBN:0781735149, PMID:15771591, PMID:15928678] |
Concepts | Cell Function (T043) |
English | antigen presentation, exogenous antigen, antigen processing and presentation of exogenous antigen |
Ontology: antigen processing and presentation of peptide antigen (C1154997)
Definition (GO) | The process in which an antigen-presenting cell expresses peptide antigen in association with an MHC protein complex on its cell surface, including proteolysis and transport steps for the peptide antigen both prior to and following assembly with the MHC protein complex. The peptide antigen is typically, but not always, processed from an endogenous or exogenous protein. [GOC:add, ISBN:0781735149, PMID:15771591] |
Concepts | Cell Function (T043) |
English | antigen presentation, peptide antigen, peptide antigen processing and presentation, antigen processing and presentation of peptide antigen |