| receptor-CD3 complex, antigen, T-cell | Molecule composed of the non-covalent association of the T-cell antigen receptor (receptors, antigen, T-cell) with the CD3 complex (antigens, CD3). This association is required for the surface expression and function of both components. The molecule consists of up to seven chains: either the alpha/beta or gamma/delta chains of the T-cell receptor, and four or five chains in the CD3 complex. (12 Dec 1998) |
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| proliferating cell nuclear antigen | Acidic nuclear protein (33 kD) highly expressed in dividing cells. Interacts with D type cyclins. (18 Nov 1997) |
| senescent cell antigen | <immunology> An antigen (62 kD) that appears on the surface of senescent erythrocytes and is immunologically cross reactive with isolated Band III protein. Seems to be recognised by an autoantibody and the immunoglobulin coated erythrocyte is then removed from circulation by cells such as Kuppfer cells of the liver that have Fc receptors. Intracellular cleavage of intact band III by a calcium activated protease, calpain, may reveal the antigen in situ. (18 Nov 1997) |
| islet cell antigen-related protein-tyrosine phosphatase | <enzyme> Receptor-like autoantigen found in insulin-dependent diabetes; genbank l76258 Registry number: EC 3.1.3.- Synonym: iar ptp (26 Jun 1999) |
| receptors, cell surface | Cell surface proteins that bind signalling molecules external to the cell with high affinity and convert this extracellular event into one or more intracellular signals that alter the behaviour of the target cell. Cell surface receptors, unlike enzymes, do not chemically alter their ligands. (12 Dec 1998) |
| T-cell-rich, B-cell lymphoma | <tumour> A B-cell lymphoma in which more than 90% of the cells are of T-cell origin, masking the large cells that form the neoplastic B-cell component. See: adult T-cell lymphoma. (05 Mar 2000) |
| acetone-insoluble antigen | A diphosphatidyl glycerol that is found in the membrane of Treponema pallidum and is the antigen detected by the Wasserman test for syphilis. (18 Nov 1997) |
| allogeneic antigen | Genetic variations of the same antigens within a given species. (05 Mar 2000) |
| antigen | Virus coded cell surface antigens that appear soon after the infection of a cell by virus, but before virus replication has begun. See: early gene. (18 Nov 1997) |
| antigen-antibody complex | The complex formed by the binding of antigen and antibody molecules. The deposition of large antigen-antibody complexes leading to tissue damage causes immune complex diseases. If the antigen is polyvalent the complex may be insoluble. Immune complexes activate complement through the classical pathway. See: glomerulonephritis, Arthus reaction, type III hypersensitivity. (12 Dec 1998) |
| antigen-antibody reaction | The phenomenon, occurring in vitro or in vivo, of antibody combining with antigen of the type that stimulated the formation of the antibody, thereby resulting in agglutination, precipitation, complement fixation, greater susceptibility to ingestion and destruction by phagocytes, or neutralization of exotoxin. See: skin test. (05 Mar 2000) |
| antigen-binding site | <immunology> In immune network theory, an idiotope, an antigenic site of an antibody that is responsible for that antibody binding to an antigenic determinant (epitope). Also used of the site on a ligand molecule to which a cell surface receptor binds. (18 Nov 1997) |
| antigen-combining site | See: paratope. (05 Mar 2000) |
| antigen excess | In a precipitation test, the presence of uncombined antigen above that required to combine with all of the antibody; precipitation may be inhibited because the presence of excess antigen gives rise to soluble antigen-antibody complexes, in vivo the resultant antigen-antibody interaction in such an antigen excess may give rise to immune complexes, which have a potential to induce cellular damage; such injury underlies the pathologic changes seen in certain immune complex diseases. (05 Mar 2000) |
| antigen interferon | <cytokine> Interferon elaborated by T lymphocytes in response to either specific antigen or mitogenic stimulation. This type II interferon can be produced by recombinant DNA technology and is similar to the interferon secreted by lymphocytes and has antiviral and antineoplastic activity. Synonym: antigen interferon, immune interferon. Pharmacological action: antineoplastic agent, antiviral agents. (20 Sep 2002) |