| MHC I | major histocompatibility complex |
|---|---|
| MHC | major histocompatibility complex antigen |
| MHC | major histocompatibility gene complex |
| antigens, CD3 | <immunology> A complex of at least five membrane-bound polypeptides in mature T-lymphocytes that are non-covalently associated with one another and with the T-cell receptor (receptors, antigen, T-cell). The CD3 complex includes the gamma, delta, epsilon, zeta, and eta chains (subunits). When antigen binds to the T-cell receptor, the CD3 complex transduces the activating signals to the cytoplasm of the T-cell. The CD3 gamma and delta chains (subunits) are separate from and not related to the gamma/delta chains of the T-cell receptor (receptors, antigen, T-cell, gamma-delta). (12 Dec 1998) |
|---|---|
| antigens, CD30 | <immunology> Differentiation antigens normally present in a small number of cells in the lymph nodes and tonsils in vivo, but also capable of being induced in a wide range of cells in vitro. They are clinically useful as tumour markers for ki-1 lymphoma (lymphoma, large-cell, ki-1) and some cases of lymphomatoid papulosis, mycosis fungoides, and hodgkin's disease. (12 Dec 1998) |
| antigens, CD31 | <immunology> Cell adhesion molecules present on virtually all monocytes, platelets, and granulocytes. Cd31 is highly expressed on endothelial cells and concentrated at the junctions between them. (12 Dec 1998) |
| antigens, CD34 | <immunology> Glycoproteins found on immature haematopoietic cells and endothelial cells. They are the only molecules to date whose expression within the blood system is restricted to a small number of progenitor cells in the bone marrow. (12 Dec 1998) |
| antigens, CD36 | <immunology> Leukocyte differentiation antigens and major platelet membrane glycoproteins present on monocytes, endothelial cells, platelets, mammary epithelial cells, and a variety of cultured cell lines. They play major roles in adhesion phenomena, signal transduction, and haematopathology. Cd36 is also the receptor for thrombospondin and malaria-infected erythrocytes. (12 Dec 1998) |
| antigens, CD4 | <immunology> 55-kD glycoproteins originally defined as differentiation antigens on T-lymphocytes, but also found on other cells including monocytes/macrophages. CD4 antigens are members of the immunoglobulin supergene family and are implicated as associative recognition elements in MHC (major histocompatibility complex) class II-restricted immune responses. On T-lymphocytes they define the helper/inducer subset. Cd4 antigens also serve as HIV receptors, binding directly to the envelope protein gp120 on HIV. The protein structure on the surface of a human cell that allows HIV to attach, enter, and thus infect a cell. CD4 receptors are present on CD4 cells (helper T-cells), macrophages and dendritic cells, among others. Normally, CD4 acts as an accessory molecule, forming part of larger structures (such as the T-cell receptor) through which Tcells and other cells signal each other. (12 Dec 1998) |
| antigens, CD40 | <immunology> Differentiation antigens found on all mature B-lymphocytes and some epithelial cells, carcinomas, and lymphoid dendritic cells. This is a member of the tumour necrosis factor superfamily. Evidence suggests that CD40-dependent activation of B-cells is important for generation of memory B-cells within the germinal centres. (12 Dec 1998) |
| antigens, CD44 | <immunology> Acidic sulfated integral membrane glycoproteins expressed in several alternatively spliced and variable glycosylated forms on a wide variety of cell types including mature T-cells, B-cells, medullary thymocytes, granulocytes, macrophages, erythrocytes, and fibroblasts. Cd44 antigens are the principle cell surface receptors for hyaluronate and this interaction mediates binding of lymphocytes to high endothelial venules. (12 Dec 1998) |
| antigens, CD45 | <immunology> High-molecular weight glycoproteins uniquely expressed on the surface of all leukocytes and their haemopoietic progenitors. The CD45 family consists of multiple members that are all products of a single gene. Cd45 expression is necessary for signalling through the T-cell receptor. (12 Dec 1998) |
| antigens, CD5 | <immunology> Glycoproteins expressed on all mature T-cells, thymocytes, and a subset of mature B-cells. Antibodies specific for CD5 can enhance T-cell receptor-mediated T-cell activation. The B-cell-specific molecule CD72 is a natural ligand for CD5. (12 Dec 1998) |
| antigens, CD55 | <immunology> Glycoproteins broadly distributed among haematopoietic and non-haematopoietic cells. Cd55 prevents the assembly of c3 convertase or accelerates the disassembly of preformed convertase, thus blocking the formation of the membrane attack complex. (12 Dec 1998) |
| antigens, CD56 | <immunology> The 140-kD isoform of ncam (neural cell adhesion molecule) containing a transmembrane domain and short cytoplasmic tail. It is expressed by all lymphocytes mediating non-MHC restricted cytotoxicity and is present on some neural tissues and tumours. (12 Dec 1998) |
| antigens, CD57 | <immunology> Oligosaccharide antigenic determinants found principally on nk cells and T-cells. Their role in the immune response is poorly understood. (12 Dec 1998) |
| antigens, CD58 | <immunology> Glycoproteins with a wide distribution on haematopoietic and non-haematopoietic cells and strongly expressed on macrophages. Cd58 mediates cell adhesion by binding to CD2 (antigens, CD2) and this enhances antigen-specific T-cell activation. (12 Dec 1998) |
| antigens, CD59 | <immunology> Small glycoproteins found on both haematopoietic and non-haematopoietic cells. Cd59 restricts the cytolytic activity of homologous complement by binding to c8 and c9 and blocking the assembly of the membrane attack complex. (12 Dec 1998) |