loading...| Preferred Name | MHC class II antigen presentation | |
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| Definitions |
Antigen presenting cells (APCs) such as B cells, dendritic cells (DCs) and monocytes/macrophages express major histocompatibility complex class II molecules (MHC II) at their surface and present exogenous antigenic peptides to CD4+ T helper cells. CD4+ T cells play a central role in immune protection. On their activation they stimulate differentiation of B cells into antibody-producing B-cell blasts and initiate adaptive immune responses. MHC class II molecules are transmembrane glycoprotein heterodimers of alpha and beta subunits. Newly synthesized MHC II molecules present in the endoplasmic reticulum bind to a chaperone protein called invariant (Ii) chain. The binding of Ii prevents the premature binding of self antigens to the nascent MHC molecules in the ER and also guides MHC molecules to endocytic compartments. In the acidic endosomal environment, Ii is degraded in a stepwise manner, ultimately to free the class II peptide-binding groove for loading of antigenic peptides. Exogenous antigens are internalized by the APC by receptor mediated endocytosis, phagocytosis or pinocytosis into endocytic compartments of MHC class II positive cells, where engulfed antigens are degraded in a low pH environment by multiple acidic proteases, generating MHC class II epitopes. Antigenic peptides are then loaded into the class II ligand-binding groove. The resulting class II peptide complexes then move to the cell surface, where they are scanned by CD4+ T cells for specific recognition (Berger & Roche 2009, Zhou & Blum 2004, Watts 2004, Landsverk et al. 2009). Authored: Garapati, P V, 2012-02-21 Edited: Garapati, P V, 2012-02-21 Reviewed: Neefjes, Jacques, 2012-05-14 |
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http://purl.obolibrary.org/obo/HINO_0022397 |
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| comment |
Antigen presenting cells (APCs) such as B cells, dendritic cells (DCs) and monocytes/macrophages express major histocompatibility complex class II molecules (MHC II) at their surface and present exogenous antigenic peptides to CD4+ T helper cells. CD4+ T cells play a central role in immune protection. On their activation they stimulate differentiation of B cells into antibody-producing B-cell blasts and initiate adaptive immune responses. MHC class II molecules are transmembrane glycoprotein heterodimers of alpha and beta subunits. Newly synthesized MHC II molecules present in the endoplasmic reticulum bind to a chaperone protein called invariant (Ii) chain. The binding of Ii prevents the premature binding of self antigens to the nascent MHC molecules in the ER and also guides MHC molecules to endocytic compartments. In the acidic endosomal environment, Ii is degraded in a stepwise manner, ultimately to free the class II peptide-binding groove for loading of antigenic peptides. Exogenous antigens are internalized by the APC by receptor mediated endocytosis, phagocytosis or pinocytosis into endocytic compartments of MHC class II positive cells, where engulfed antigens are degraded in a low pH environment by multiple acidic proteases, generating MHC class II epitopes. Antigenic peptides are then loaded into the class II ligand-binding groove. The resulting class II peptide complexes then move to the cell surface, where they are scanned by CD4+ T cells for specific recognition (Berger & Roche 2009, Zhou & Blum 2004, Watts 2004, Landsverk et al. 2009). Authored: Garapati, P V, 2012-02-21 Edited: Garapati, P V, 2012-02-21 Reviewed: Neefjes, Jacques, 2012-05-14 |
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| definition source |
Pubmed19703008 Pubmed15224094 Pubmed15531770 Reactome, http://www.reactome.org Pubmed19092054 Pubmed11684289 Pubmed8689559 Pubmed19217269 Pubmed9316394 |
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| label |
MHC class II antigen presentation |
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| located_in | ||
| prefixIRI |
HINO:0022397 |
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| prefLabel |
MHC class II antigen presentation |
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| seeAlso |
Reactome Database ID Release 432132295 ReactomeREACT_121399 GENE ONTOLOGYGO:0019886 |
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| has_part |
http://purl.obolibrary.org/obo/HINO_0018119 http://purl.obolibrary.org/obo/HINO_0018132 http://purl.obolibrary.org/obo/HINO_0018131 http://purl.obolibrary.org/obo/HINO_0018130 http://purl.obolibrary.org/obo/HINO_0018134 http://purl.obolibrary.org/obo/HINO_0018133 http://purl.obolibrary.org/obo/HINO_0018135 http://purl.obolibrary.org/obo/HINO_0018163 http://purl.obolibrary.org/obo/HINO_0018160 http://purl.obolibrary.org/obo/HINO_0018162 http://purl.obolibrary.org/obo/HINO_0018129 http://purl.obolibrary.org/obo/HINO_0018126 http://purl.obolibrary.org/obo/HINO_0018125 http://purl.obolibrary.org/obo/HINO_0018127 http://purl.obolibrary.org/obo/HINO_0018121 http://purl.obolibrary.org/obo/HINO_0018124 http://purl.obolibrary.org/obo/HINO_0018122 http://purl.obolibrary.org/obo/HINO_0018120 http://purl.obolibrary.org/obo/HINO_0018158 http://purl.obolibrary.org/obo/HINO_0018155 http://purl.obolibrary.org/obo/HINO_0018156 http://purl.obolibrary.org/obo/HINO_0018157 |