ABO blood group
See Blood Groups appendix.

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ABO blood group .ā-(.)bē-'ō- n one of the four blood groups A, B, AB, or O comprising the ABO system

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the major human blood group system, dependent on the presence or absence of A and B antigens, which are largely glycolipids on the cell membrane. The gene for A is responsible for synthesis of N-acetyl-α-D-galactosaminyl transferase, whereas that for B is responsible for α-D-galactosyl transferase. Either A or B is created when one of these hexasaccharides is positioned by a specific transferase in 1→3 linkage to the β-D-galactose of an H-active oligosaccharide. Type O occurs when neither transferase is present or, very rarely (Bombay phenotype), when H antigen does not exist. When both transferases are present, type AB results. Differences in degree of transferase activity are determined at the same locus: weak transferase gives rise to weak antigens (A2, A3Ax, B3Bx). Similar oligosaccharides, especially in bacterial cell walls, immunize persons lacking A or B so that their serum contains anti-A or anti-B activity. A and B antigens are on the mucopolysaccharides of secretors; persons with dominant genes have H-active mucoids.

Medical dictionary. 2011.

Look at other dictionaries:

  • ABO blood group — noun Date: 1949 any of the four blood groups A, B, AB, and O comprising the ABO system …   New Collegiate 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

  • ABO blood group system — noun a classification system for the antigens of human blood; used in blood transfusion therapy; four groups are A and B and AB and O • Syn: ↑ABO system, ↑ABO group • Hypernyms: ↑classification system * * * ABO blood group system /ā bē ōˈ blud… …   Useful english dictionary

  • ABO blood group system — ▪ biology  method of classifying human blood on the basis of the inherited properties of red blood cells (erythrocyte) (erythrocytes (erythrocyte)) as determined by their possession or lack of the antigens (antigen) A and B, which are carried on… …   Universalium

  • ABO blood group system — Probably the best known of the blood group systems, involves a single gene locus that codes for a fucosyl transferase. If the H gene is expressed then fucose is added to the terminal galactose of the precursor oligosaccharide on the red cell… …   Dictionary of molecular biology

  • ABO blood-group system — Classification of human blood according to whether red blood cells (erythrocytes) have or lack the inherited antigens called A (including A1 and A2) and B on their surface. Blood can be type O (lacking both), type A (having only A), type B… …   Universalium

  • 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 — n. 1. any of several groups, or systems, of agglutinogens present on the surface of normal red blood cells, such as the ABO SYSTEM 2. BLOOD TYPE …   English World dictionary

  • blood group — ► NOUN ▪ any of various types of human blood classified according to their compatibility in transfusion, especially by means of the ABO system …   English terms dictionary

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