| ARB | adrenergic receptor binder |
|---|---|
| ARIA | acetylcholine receptor-inducing activity; automated radioimmunoassay |
| ARM | adrenergic receptor material; aerosol rebreathing method; ambulatory renal monitor; anorectal manome... |
| ASGR | asialoglycoprotein receptor |
| BAR | bariatrics; barometer, barometric; beta-adrenergic receptor |
| P antigen | <haematology, immunology> Antigenic determinant on the surface of human red blood cells to which the Donath Landsteiner antibody reacts. This antibody binds in the cold (a cold IgG), but elutes from red cells at 37쵣, is particularly associated with tertiary syphylis and its binding causes paroxysmal nocturnal haemoglobinuria. (18 Nov 1997) |
|---|---|
| R antigen | Those that produce active haemolysins (O and S) which cause a zone of clear haemolysis on the blood agar medium in the area of the colony; beta-haemolytic streptococci are divided into groups (A to O) on the basis of cell wall C carbohydrate (see Lancefield classification); Group A (in the strains pathogenic for man) comprises more than 50 types (designated by Arabic numerals) determined by cell wall M protein, which seems to be associated closely with virulence and is produced chiefly by strains with matt or mucoid colonies, in contrast to nonvirulent, glossy colony-producing strains; other surface protein antigens such as R and T (T substance), and the nucleoprotein fraction (P substance) seem to be of less importance. The more than 20 extracellular substances elaborated by strains of beta-haemolytic streptococci include erythrogenic toxin (elaborated only by lysogenic strains), deoxyribonuclease (streptodornase), haemolysins (streptolysins O and S), hyaluronidase, and streptokinase. Synonym: haemolytic streptococci. (05 Mar 2000) |
| M antigen | An antigen found in the cell of Streptococcus pyogenes; associated with virulence. See: beta-haemolytic streptococci. (05 Mar 2000) |
| receptors, antigen | Molecules on the surface of b- and T-lymphocytes that recognise and combine with specific antigens. (12 Dec 1998) |
| receptors, antigen, B-cell | Immunoglobulin molecules on the surface of B-lymphocytes that recognise and bind antigen. (12 Dec 1998) |
| receptors, antigen, T-cell | Molecules on the surface of T-lymphocytes that recognise and combine with antigens. The receptors are non-covalently associated with a complex of several polypeptides collectively called CD3 antigens (antigens, CD3). Recognition of foreign antigen and the major histocompatibility complex is accomplished by a single heterodimeric antigen-receptor structure, composed of either alpha-beta (receptors, antigen, T-cell, alpha-beta) or gamma-delta (receptors, antigen, T-cell, gamma-delta) chains. (12 Dec 1998) |
| receptors, antigen, T-cell, alpha-beta | T-cell receptors composed of CD3-associated alpha and beta polypeptide chains and expressed primarily in CD4+ or CD8+ T-cells. Unlike immunoglobulins, the alpha-beta T-cell receptors recognise antigens only when presented in association with major histocompatibility (MHC) molecules. (12 Dec 1998) |
| receptors, antigen, T-cell, gamma-delta | T-cell receptors composed of CD3-associated gamma and delta polypeptide chains and expressed primarily in CD4-/CD8- T-cells. The receptors appear to be preferentially located in epithelial sites and probably play a role in the recognition of bacterial antigens. The T-cell receptor gamma/delta chains are separate and not related to the gamma and delta chains which are subunits of CD3 (see antigens, CD3). (12 Dec 1998) |
| receptors, very late antigen | Members of the integrin family appearing late after T-cell activation. They are a family of proteins initially identified at the surface of stimulated T-cells, but now identified on a variety of cell types. At least six vla antigens have been identified as heterodimeric adhesion receptors consisting of a single common beta-subunit and different alpha-subunits. (12 Dec 1998) |
| Gerbich antigen | glycophorin C |
| Vi antigen | Virulence antigen, an external capsular antigen of enterobacteria formerly thought to be related to increased virulence. (05 Mar 2000) |
| partial antigen | <immunology, molecular biology> Could be considered an isolated epitope: although a hapten (by definition) has an antibody directed against it, the hapten alone will not induce an immune response if injected into an animal, it must be conjugated to a carrier (usually a protein). The hapten constitutes a single antigenic determinant, perhaps the best known example is dinitro phenol (DNP) that can be conjugated to BSA and against which antiDNP antibodies are produced (antibodies to the BSA can be adsorbed out). Because the hapten is monovalent, immune complex formation will be blocked if the soluble hapten is present as well as the hapten carrier conjugate (assuming there is more than one hapten per carrier then an immune precipitate can be formed). Competitive inhibition by the soluble small molecule is sometimes referred to as haptenic inhibition and this term has carried over into lectin mediated haemagglutination where monosaccharides are added to try to block haemagglutination: the blocking sugar defines the specificity of the lectin. (18 Nov 1997) |
| viral antigen | Those antigens specified by the viral genome (often coat proteins) that can be detected by a specific immunological response. Often of diagnostic importance. (18 Nov 1997) |
| C carbohydrate antigen | An antigen found in the cell wall of Streptococcus pneumoniae. See: beta-haemolytic streptococci. (05 Mar 2000) |
| CD antigen | <immunology> Differentiation antigens residing on human leukocytes. CD stands for cluster of differentiation, which refers to groups of monoclonal antibodies that show similiar reactivity with certain subpopulations of antigens. The subpopulations of antigens are also known by the same CD designation. (12 Dec 1998) |