Biomaterial Database

Class II antigen processing: analysis of compartments and functions. 1996

C V Harding

Institute of Pathology, Program in Cell Biology, Case Western Reserve University, Cleveland, OH 44106, USA.

The endocytic and phagocytic pathways are composed of a series of vesicular or vacuolar organelles within the cytoplasm in which exogenous proteins or particles are processed. This processing includes catabolism of protein antigens by proteases that exist within endosomes, lysosomes, phagosomes, and phagolysosomes. Antigen processing produces peptides that bind to class II MHC (MHC-II) molecules, which also target to vesicular compartments. Multiple different vesicular compartments may contribute to antigen processing, although some compartments appear to be specialized in order to perform certain antigen processing functions. The relative levels of MHC-II molecules, processing enzymes, and other specialized molecules (e.g., HLA-DM) are among the variables that determine the relative contribution of different compartments. Recent studies have begun to identify specific compartments that mediate certain antigen processing functions, including the binding of immunogenic peptides to MHC-II molecules.

UI	MeSH Term	Description	Entries
D008954	Models, Biological	Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.	Biological Model,Biological Models,Model, Biological,Models, Biologic,Biologic Model,Biologic Models,Model, Biologic
D010587	Phagocytosis	The engulfing and degradation of microorganisms; other cells that are dead, dying, or pathogenic; and foreign particles by phagocytic cells (PHAGOCYTES).	Phagocytoses
D002451	Cell Compartmentation	A partitioning within cells due to the selectively permeable membranes which enclose each of the separate parts, e.g., mitochondria, lysosomes, etc.	Cell Compartmentations,Compartmentation, Cell,Compartmentations, Cell
D004705	Endocytosis	Cellular uptake of extracellular materials within membrane-limited vacuoles or microvesicles. ENDOSOMES play a central role in endocytosis.	Endocytoses
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D000949	Histocompatibility Antigens Class II	Large, transmembrane, non-covalently linked glycoproteins (alpha and beta). Both chains can be polymorphic although there is more structural variation in the beta chains. The class II antigens in humans are called HLA-D ANTIGENS and are coded by a gene on chromosome 6. In mice, two genes named IA and IE on chromosome 17 code for the H-2 antigens. The antigens are found on B-lymphocytes, macrophages, epidermal cells, and sperm and are thought to mediate the competence of and cellular cooperation in the immune response. The term IA antigens used to refer only to the proteins encoded by the IA genes in the mouse, but is now used as a generic term for any class II histocompatibility antigen.	Antigens, Immune Response,Class II Antigens,Class II Histocompatibility Antigen,Class II Major Histocompatibility Antigen,Ia Antigens,Ia-Like Antigen,Ia-Like Antigens,Immune Response Antigens,Immune-Associated Antigens,Immune-Response-Associated Antigens,MHC Class II Molecule,MHC II Peptide,Class II Antigen,Class II Histocompatibility Antigens,Class II MHC Proteins,Class II Major Histocompatibility Antigens,Class II Major Histocompatibility Molecules,I-A Antigen,I-A-Antigen,IA Antigen,MHC Class II Molecules,MHC II Peptides,MHC-II Molecules,Antigen, Class II,Antigen, I-A,Antigen, IA,Antigen, Ia-Like,Antigens, Class II,Antigens, Ia,Antigens, Ia-Like,Antigens, Immune-Associated,Antigens, Immune-Response-Associated,I A Antigen,II Peptide, MHC,Ia Like Antigen,Ia Like Antigens,Immune Associated Antigens,Immune Response Associated Antigens,MHC II Molecules,Molecules, MHC-II,Peptide, MHC II,Peptides, MHC II
D017951	Antigen Presentation	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)	Antigen Processing,Antigen Presentations,Antigen Processings