Blood-group specific substances

These specific substances or blood group factors are detected by their property of inhibiting agglutinin reactions between human erythrocytes and heterologous human sera. This is the so-called isoagglutinin test which can detect the factors in dilutions of more than 1 part in 10 million. An even more sensitive but less specific test is their power to inhibit hemolysis of sheep s erythrocytes by the serum of rabbits immunized with certain human corpuscles. 

Little is known of the chemical nature of the group specific substances proper for they are extremely difficult to isolate. Active alcoholic extracts have been obtained from erythrocytes by various workers and in some instances these extracts were shown to contain carbohydrates. 

Kossjakow i claims to have isolated a polysaccharide in this way, by a relatively simple procedure, but the reviewer and coworkers have been unable to obtain active material by this method. It does appear that the specific substances contain carbohydrate, lipid, and possibly polypeptide constituents similar perhaps to the Forsman antigen (see below) and that the linkages between these constituents are very fragile. 

In all cases where the chemical properties of these preparations have been studied the active material appears to be predominantly carbohydrate in nature, containing in the case of the A factor 50-70% of reducing sugar, 5.7% nitrogen and giving by colorimetric estimations 25-30% of glucosamine on hydrolysis. 

The latter was isolated in the form of fully methylated methyl fuco-side, i. e., methyl 2,3,4-trimethyl-a-L-fucoside (XLVII), a compound previously obtained from methylated gum tragacanth. The recognition of this particular derivative indicates that the L-fucose residues in part at least must constitute end groups linked glycosidically to the rest of the molecule. The same compound was isolated by methylation and 

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Watkins, W. M., Blood Group Specific Substances in Glycoproteins, p,... 

W17. Witebsky, E., Klendshoj, N. C., and Vaughan, S. L., Occurrence of blood group specific substances in gastric juice of patients with pernicious anemia. Proc. Soc. Exptl. Biol. Med. 49, 633-636 (1942). 

Blood-group specific substances have been isolated in amount of about 3 mg. per 100 cc. from the salivas of persons of the A, B, and 0 types (90). So-called nonsecretors excrete a similar polysaccharide which does not give the serological reactions typical of the blood-specific substances. 

Watkins, W. M., 1972, Blood-group specific substances, in Glycoproteins Their Composition, Structure and Function, (A. Gottschalk, ed.), 2nd ed., pp. 830-891, Elsevier Publishing Co., Amsterdam. 

Although no complete investigations of the structure of the blood group substances have yet been reported, it is evident from the information available that all the material so far studied is predominantly carbohydrate in nature, and, as can be seen from Table III, preparations from widely different sources have many properties in common, for example, elementary analysis, specific rotation and the like. It is of interest to note that almost all the substances obtained from nonhuman sources display blood group A or blood group O activity, while human material is the most convenient source of the blood group B substance. The majority of the work carried out so far has dealt with blood group A substances. 

With individuals of blood group 0, injection of A and B substances gave a big increase in the amounts of precipitins. For example, the specific antibodies to the blood group A substance could be obtained from the specific precipitate by the use of 15% sodium chloride for dissociating... 

Substances Having Anti-blood Group Specificity. A Discussion on the Specificity of Helix Agglutinins, Vox Sanguinis (1968) 14, 321. 

Extensive information on the carbohydrate-binding specificity of the Helix pomatia lectin was obtained by examining the extent to which a large number of sugars inhibited the precipitation reaction between agglutinin and human blood-group A substance or Salmonella typhinurium SH 180 lipopolysaccharide83,178,581,582 (see Table XI). 

Carbohydrate-specificity studies involving hemagglutination in-hibition61 100,587 and sugar displacement from Sephadex,587 and an immunosorbent of human blood-group A substance,587 gave essentially the same results. 

The immunochemical studies of Kabat and coworkers200 686 revealed some striking subtleties in Lotus tetragonolobus sugar-specificity. Precipitin reactions between the lectin and several blood-group H substances demonstrated strong affinity of the lectin for this determinant. H substances precipitated 83-88% of the purified Lotus lectin at... 

Kla. Kabat, E., Bendich, A., and Bezer, A. E., Immunochemical studies on blood groups. II. Properties of the blood group A substance from pools of hog stomach of specific precipitates composed of A substance and homologous human antihody. J. Exptl. Med. 83, 447 (1946). 

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