Erythrocytes sialic acid determination

Abstract Persistent colonization of the human stomach by Helicobacter pylori is a risk factor for the development of peptic ulcer disease and gastric cancer. Adhesion of microbes to the target tissue is an important determinant for successful initiation, establishment and maintenance of infection, and a variety of different candidate carbohydrate receptors for H. pylori have been identified. Here the different the binding specifities, and their potential role in adhesion to human gastric epithelium are described. Finally, recent findings on the roles of sialic acid binding SabA adhesin in interactions with human neutrophils and erythrocytes are discussed. 

Schauer R (1992). Sialic acids regulate cellular and molecular recognition. In Ogura H, Hasegawa A, Suami T, Carbohydrates, Kodansha Ltd., Tokyo, pp. 340-354. Jancik J, Schauer R (1974). Sialic acid-a determinant of the life-time of rabbit erythrocytes. Hoppe Seylers Z Physiol. Chem. 355 395-400. 

Sialic acid was the first virus receptor identified. Hirst and McClelland and Hare discovered that influenza virus is able to hemagglutinate and that adsorbed virus is eluted from erythrocytes on incubation at 37°C, indicating an enzymatic destruction of a receptor substance on the cells [1, 2]. When a similar enzymatic activity was subsequently detected in Vibrio cholerae cultures, the term receptor-destroying enzyme was introduced [3]. The substance released by the viral enzyme from soluble hemagglutination inhibitors was initially characterized as a carbohydrate of low molecular weight [4] and then identified in crystalline form as A-acetyl-o-neuraminic acid [5]. Thus, it was clear that the receptor determinant of influenza virus was sialic acid and that the viral enzyme was a neuraminidase. Furthermore, for the first time an important biological function of sialic acid had been identified. 

Though the role of A-acetylneuraminic acid as a receptor determinant for influenza virus has been known for 40 years, the actual receptor used by this virus to infect cells has not been identified unequivocally. As sialic acid is a frequent sugar on glycoproteins and glycolipids of vertebrate cells, most surface components contain A-acetylneuraminic acid or a derivative of it. All sialylated molecules present on the cell surface are potential receptors for influenza viruses or paramyxoviruses provided they contain sialic acid according to the requirements discussed above (Section 4.1). In the case of erythrocytes, the majority of the surface-bound sialic acid is present on glycophorin. Following isolation from... 

JBecause of the lack of susceptibility to neuraminidase of some of the sialic acid residues at the surface of the cell, quantitative determination has been successful only when the major proportion of these residues is released. These amounts vary widely, from 3 x 10 residues of sialic acid per human erythrocyte (Madoff et aL, 1964), to 3 x 10 residues per human platelet (Bray and Alexander, 1969), to approxi-... 

Both forms of sialic acid, N-acetyl- and N-glycolylneuraminic acid (cf. Chapter 1), may coexist at the surface of the same cell, as shown in the murine TA3-Ha cancer cell by Codington et aL (1970). In the erythrocyte, the proportion ofN-acetyl- and N-glycolylneuraminic acid is similar to that of these compounds in other tissues, and varies with the animal species (Klenk, 1958a). No information is available at the present time on the occurrence and relative proportions of the O-acetyl derivatives of sialic acid at the surface of the mammalian cell. The absolute and relative amounts of sialic acid residues linked either to glycoproteins or to glycolipids vary widely and have been determined only on the erythrocytes of a few animal species (Uhlenbruck and Wintzer, 1970). 

Gattegno, L., Bladier, D., and Comillot, P., 1974, The role of sialic acid in the determination of survival of rabbit erythrocytes in the circulation. Carbohydrate Res. 34 361-369. 

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