| nonprecipitating antibody | Antibody that, under conditions normally employed in precipitin tests, is refractory to precipitation by specific antibody, demonstrable when antigen is added serially in small amounts; nonprecipitating antibody will precipitate under special conditions such as addition of complement. Synonym: nonprecipitable antibody. (05 Mar 2000) |
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| normal antibody | Antibody demonstrable in the serum or plasma of various persons or animals not known to have been stimulated by specific antigen, either artificially or as the result of naturally occurring contact. Synonym: natural antibody. (05 Mar 2000) |
| syndrome, antiphospholipid antibody | An immune disorder characterised by the presence of abnormal antibodies in the blood associated with certain medical conditions including abnormal blood clotting, migraine headaches, premature miscarriage, and low blood platelet counts (thrombocytopenia). (12 Dec 1998) |
| direct fluorescent antibody | The straightforward detection of antigens using fluorescent labelled antigen-specific antibody. Because detection of the antigen in a substrate of patient sample (cellular smear, fluid or patient-inoculated culture medium) is the goal, direct fluorescent antibody is seldom quantitative. (05 Mar 2000) |
| direct fluorescent antibody test | Test for tissue antigen using either a direct method, by conjugation of antibody with fluorescent dye (fluorescent antibody technique, direct) or an indirect method, by formation of antigen-antibody complex which is then labelled with fluorescein-conjugated anti-immunoglobulin antibody (fluorescent antibody technique, indirect). The tissue is then examined by fluorescence microscopy. (12 Dec 1998) |
| double antibody immunoassay | A method of separating antibody-bound antigen (e.g., insulin) from free antigen by precipitating the former with antibody specific for immunoglobulin. Synonym: double antibody immunoassay, double antibody method. (05 Mar 2000) |
| double antibody method | A method of separating antibody-bound antigen (e.g., insulin) from free antigen by precipitating the former with antibody specific for immunoglobulin. Synonym: double antibody immunoassay, double antibody method. (05 Mar 2000) |
| double antibody precipitation | A method of separating antibody-bound antigen (e.g., insulin) from free antigen by precipitating the former with antibody specific for immunoglobulin. Synonym: double antibody immunoassay, double antibody method. (05 Mar 2000) |
| double antibody sandwich assay | For antigen; an application of the ELISA method in which material being tested for antigen is added to wells coated with known antibody; the presence of antigen fixed to the antibody coat can be determined either directly, by adding human antibody linked to the enzyme of the indicator system, or indirectly, by first adding unlabelled known antibody, the attachment of which to the antigen can be demonstrated by addition of immunoglobulin-specific antibody linked to the enzyme. (05 Mar 2000) |
| idiotype antibody | <immunology> An antibody directed against the antigen specific part of the sequence of an antibody or T-cell receptor and thus recognise the binding sites of other antibodies. In principle an anti-idiotype antibody should inhibit a specific immune response and they are important to the regulation of the immune system. (13 Nov 1997) |
| IgM antibody capture ELISA | Developed to impart significant improvement in assay specificity to indirect ELISA procedures for IgM isotype antibodies. Solid-phase support (usually microtitre plate wells) are coated with anti-human IgM antibodies capable of binding all IgM isotype antibodies present in the specimen. Reagent antigen is then added, followed by enzyme-labelled antigen-specific antibodies. If IgM antibodies specific for the antigen in question are present, the "sandwich" complex will result in enzymatic colour-change proportional to the concentration of IgM-specific antibody present. This technique appears to be the method of choice in many highly specific and more sensitive assays for IgM infectious disease antibodies. Acronym: MAC ELISA (05 Mar 2000) |
| immobilizing antibody | Antibody, evoked during syphilitic infections, possessing specific affinity for Treponema pallidum, and which in the presence of complement immobilises the organism. Synonym: immobilizing antibody, treponemal antibody. (05 Mar 2000) |
| incomplete antibody | An "incomplete" form of antibody that may coat antigen, but which according to the "lattice theory" does not have a second receptor for attachment to another molecule of antigen; in the case of Rh+ erythrocytes, such an anti-Rh antibody may coat the cells but not cause them to agglutinate in saline; however, agglutination does occur when such coated cells are suspended in serum or other protein media, such as albumin, therefore called serum agglutinin. Synonym: incomplete antibody, inhibiting antibody. (05 Mar 2000) |
| indirect fluorescent antibody | The detection of antibodies to specific antigenic material in the substrate using fluorescent microscopy. Using fluorescent conjugated antibodies which are specific for a particular isotype of antibody, it is possible to distinguish IgG, IgA and IgM isotypes of specific antibodies using indirect fluorescent antibody. This sensitive technique is highly specific in well-trained hands and recent developments in the establishment of internationally recognised standard materials have led to accurate quantitation of antibody concentrations through endpoint titration (the highest serial dilution of specimen at which specific fluorescence remains) and through measuring visual intensity of fluorescence compared to known reference standard material. (05 Mar 2000) |
| inhibiting antibody | An "incomplete" form of antibody that may coat antigen, but which according to the "lattice theory" does not have a second receptor for attachment to another molecule of antigen; in the case of Rh+ erythrocytes, such an anti-Rh antibody may coat the cells but not cause them to agglutinate in saline; however, agglutination does occur when such coated cells are suspended in serum or other protein media, such as albumin, therefore called serum agglutinin. Synonym: incomplete antibody, inhibiting antibody. (05 Mar 2000) |