Evidence for Sialylated Type 1 Blood Group Chains on Human Erythrocyte Membranes Revealed by Agglutination of Neuraminidase-Treated Erythrocytes with Waldenström’s Macroglobulin IgM^WOO and Hybridoma Antibody FC 10.2

Abstract

Haemagglutination studies have been performed with untreated and neuraminidase- treated human erythrocytes of the three Lewis antigen types Le(a^-b^-), Le(a^+b^-) and Le(a^-b^+) using two monoclonal antibodies, IgM^WOO and FC 10.2, which were previously shown to recognize the type 1 based blood group chains: Ga1β1→3G1cNAcβ1→3Ga1β1→ 4Glc/GlcNAc (for explanation of abbreviations see table IV legend). Both antibodies behaved as cold agglutinins with neuraminidase-treated but not with untreated erythrocytes of the three Lewis antigen types. Neuraminidase-treated erythrocytes of i antigen type were similarly agglutinated. This haemagglutination was specifically inhibited by the type 1 based milk oligosaccharide lacto-N-tetraose. Thus, there is strong evidence for the occurrence of sialylated type 1 chains on human erythrocyte membranes of I and i antigen types. In addition, evidence for the presence of type 1 chains which are both sialylated and fucosylated was obtained by (1) haemagglutination of Le(a^+ b^-) erythrocytes with the monoclonal antibody 19.9; (2) increased haemagglutination of neuraminidase-treated erythrocytes with anti-H antibodies of Bombay serum; (3) increased haemagglutination of neuraminidasetreated Le(a^+ b^-) cells with anti-Le^a antibodies, and (4) the appearance of Le^a antigen activity on neuraminidase-treated erythrocytes of Le(a^- b+) type.