| soluble antigen | Viral antigen that remains in solution after the particles of virus have been removed by means of centrifugation; in the case of the influenza viruses, it is the internal helical structure, free of the external envelope. Synonym: S antigen. (05 Mar 2000) |
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| somatic antigen | An antigen located in the cell wall of a bacterium in contrast to one in the flagella (flagellar antigen) or in a capsule (capsular antigen). (05 Mar 2000) |
| species-specific antigen | Antigenic components in the tissues and fluids of members of a species of animal, by means of which various species may be immunologically distinguished; e.g., serum albumin of horses is immunologically different from that of man, dogs, sheep, and so on. (05 Mar 2000) |
| Streptococcus M antigen | The somatic antigen associated with virulence and type specificity of group A streptococci. Synonym: M protein. (05 Mar 2000) |
| D antigen | One of 6 antigens that compose the Rh locus. Antibody induced by D antigen is the most frequent cause of haemolytic disease of the newborn. (05 Mar 2000) |
| delta antigen | A defective virus, containing particles of RNA nucleoprotein in virion-like form, present in patients with acute hepatitis b and chronic hepatitis. Officially this is classified as a subviral satellite RNA (RNA, satellite). (12 Dec 1998) |
| Dharmendra antigen | A chloroform-ether extracted suspension of Mycobacterium leprae; used to produce the Fernandez reaction in a lepromin test. (05 Mar 2000) |
| Di antigen | diego blood group |
| differentiation antigen | Any large structural macromolecule that can be detected by immune reagents and that also is associated with the differentiation of a particular cell type or types. Many cells can be identified by their possession of a unique set of differentiation antigens. There should be no implication that the antigens cause differentiation. (18 Nov 1997) |
| Ia antigen | Antigens coded for by the I region of the MHC complex. The majority, if not all, such antigens are Class II molecules composed of _ and _ polypeptide chains. (18 Nov 1997) |
| incomplete 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) |
| InV group antigen | Allotypic antigens that are present on human kappa immunoglobulin light chains. Synonym: InV group antigen. (05 Mar 2000) |
| Ir associated antigen | Antigens coded for by IR (immune response) genes or antigens coded for by the genome close to the IR genes. See: Ia antigens. (18 Nov 1997) |
| O antigen | Somatic antigen of enteric gram-negative bacteria. External part of cell wall lipopolysaccharide. See: H antigen. See ABO blood group, Blood Groups appendix. (05 Mar 2000) |
| O-antigen depolymerase | <enzyme> Cleaves surface o-polysaccharide (o-antigen)of salmonella anatum Registry number: EC 3.2.1.- (26 Jun 1999) |