blood group antigens

blood group antigens
the antigens responsible for specificities of blood groups; those of the ABO and Lewis blood groups were the first to be characterized. They are formed by sequential addition of monosaccharide moieties to any of several different types of precursor substances; addition of one moiety produces the Lewis antigen, addition of a second produces the H antigen, and addition of a third produces either the A or the B antigen. Secreted blood group antigens (in individuals with the secretor phenotype) are glycoproteins, and red cell antigens are glycosphingolipids; the oligosaccharide chains determining blood group specificity are the same in both.

Blood group antigens. (Diagram), Synthesis of ABO groups. The enzyme produced by the H gene attaches a fucose residue (Fuc) to the terminal galactose (Gal) of the precursor oligosaccharide. Individuals possessing an A gene then attach N-acetylgalactosamine (NAGA) to this galactose; those with a B gene attach another galactose, producing A and B antigens, respectively. NAG=N-acetylglucosamine. (Table), Genotypes and antigens of the ABO system.

Medical dictionary. 2011.

Look at other dictionaries:

  • blood group antigens — The set of cell surface antigens found chiefly, but not solely, on blood cells. More than fifteen different blood group systems are recognized in humans. There may be naturally occurring antibodies without immunization, especially in the case of… …   Dictionary of molecular biology

  • MN blood group antigens — A pair of blood group antigens governed by genes that segregate independently of the ABO locus. The alleles are co dominant and there are three types MM, NN, and MN. Glycophorin has M or N activity and this is associated with oligosaccharides… …   Dictionary of molecular biology

  • blood group — Med. any of various classes into which human blood can be divided according to immunological compatibility, based on the presence or absence of specific antigens on red blood cells. Also called blood type. Cf. ABO system, Rh factor. [1915 20] * * …   Universalium

  • blood group — blood′ group n. med any of various classes into which human blood can be divided according to immunological compatibility based on the presence or absence of specific antigens on red blood cells Also called blood type Compare ABO system Rh factor …   From formal English to slang

  • Blood group — An inherited feature on the surface of the red blood cells. A series of related blood types constitute a blood group system such as the Rh or the ABO system. The frequencies of the ABO and Rh blood types vary from population to population. In the …   Medical dictionary

  • blood group — noun human blood cells (usually just the red blood cells) that have the same antigens • Syn: ↑blood type • Hypernyms: ↑blood • Hyponyms: ↑A, ↑type A, ↑group A, ↑B, ↑ …   Useful english dictionary

  • blood group — any one of the many types into which a person s blood may be classified, based on the presence or absence of certain inherited antigens on the surface of the red blood cells. Blood of one group contains antibodies in the serum that react against… …   The new mediacal dictionary

  • ABO blood group system — ABO redirects here. For other uses, see ABO (disambiguation). H substance redirects here. For use in inflammation, see histamine. ABO blood group antigens present on red blood cells and IgM antibodies present in the serum The ABO blood group… …   Wikipedia

  • Rh blood group system — Rh redirects here. For Siddharta, see Rh (album). For the band, see The RH Factor. The Rh (Rhesus) blood group system (including the Rh factor) is one of the currently 30 human blood group systems. It is clinically the most important blood group… …   Wikipedia

  • Human blood group systems — The International Society of Blood Transfusion (ISBT) currently recognises 30 major blood group systems (including the ABO and Rh systems). [cite web |url=… …   Wikipedia

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