| conjugated hapten | A hapten that may cause the production of antibodies when it has been covalently linked to protein. Synonym: conjugated antigen. (05 Mar 2000) |
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| half-hapten | A substance that elicits an antigen-antibody reaction, but no precipitation. (05 Mar 2000) |
| hapten | <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) |
| hapten inhibition of precipitation | Inhibition of precipitation that occurs when the precipitin has combined with hapten of the same specificity as the subsequently added antigen. (05 Mar 2000) |
| Forssman hapten | A glycolipid from mammalian organs. Compare: Forssman antibody, Forssman antigen. (05 Mar 2000) |
| aberrant complex | An anomalous electrocardiographic complex, more specifically an abnormal ventricular complex caused by abnormal intraventricular conduction of a supraventricular impulse. (05 Mar 2000) |
| activated complex | <chemistry> State of highest energy during a reaction. When reactants form the activated complex, bond breaking and bond formation is occurring. Synonym: transition state. (09 Jan 1998) |
| AIDS dementia complex | <immunology> A frequent cerebral condition in people with AIDS that results in the loss of cognitive capacity, affecting the ability to function in a social or occupational setting. Its cause has not been determined exactly, but may result from HIV infection of cells in the brain or an inflammatory reaction to such infection. (09 Oct 1997) |
| aids-related complex | A prodromal phase of infection with the human immunodeficiency virus (HIV). Laboratory criteria separating aids-related complex (arc) from aids include elevated or hyperactive B-cell humoral immune responses, compared to depressed or normal antibody reactivity in aids; follicular or mixed hyperplasia in arc lymph nodes, leading to lymphocyte degeneration and depletion more typical of aids; evolving succession of histopathological lesions such as localization of kaposi's sarcoma, signaling the transition to the full-blown aids. (12 Dec 1998) |
| alpha-keto acid dehydrogenase complex | See: alpha-keto acid dehydrogenase. Anaerobic dehydrogenase, an enzyme (usually a pyridinoenzyme) catalyzing the transfer of hydrogen from some metabolite to some acceptor molecule (e.g., NAD+, cytochrome) other than oxygen; e.g., lactate dehydrogenase's, isocitrate dehydrogenase's, and others in EC class 1, excluding those listed under aerobic dehydrogenase. (05 Mar 2000) |
| alpha-ketoglutarate dehydrogenase complex | alpha-ketoglutarate dehydrogenase |
| amygdaloid complex | Almond-shaped group of basal nuclei anterior to the inferior horn of the lateral ventricle of the brain, within the temporal lobe. The amygdala is part of the limbic system. (12 Dec 1998) |
| anomalous complex | A complex in the electrocardiogram differing significantly from the physiologic type in the same lead. (05 Mar 2000) |
| antennal complex | <cell biology> Light harvesting complexes (LHC) of protein and pigment in or on photosynthetic membranes of bacteria are organised into arrays, called antennae. They transfer photon energy to reaction centres. (18 Nov 1997) |
| antennapedia complex | A set of mutations that cause developmental defects in the limbs and appendages of the fruit fly Drosophila melanogaster, such as the development of legs (-pedia) in the places where antennae are supposed to be. (09 Oct 1997) |