Characterization of an epitope (determinant) structure in a developmentally regulated glycolipid antigen defined by a cold agglutinin Fl, recognition of α-sialosyl and α- l-fucosyl groups in a branched structure

Abstract

The antibody Fl shows preferential reactivity with adult erythrocytes over newborn erythrocytes, and its reactivity is abolished by sialidase treatment of the erythrocyte. The antibody was found to recognize binary determinants linked to the branched lacto-N-isooctaosylceramide 1 1 All sugars in abbreviated form are assumed to have the d configuration (except fucose which has the l configuration), to be in the pyranose form, and to be linked at O-1 (except sialic acid which is linked at O-2) in oligosaccharides. ▪ R = OH, or αGalNAc→3, or αGal→3 residue The presence of an N-acetylneuraminyl group at one end and l-fucosyl group at the other end is essential for the reactivity of the antibody. A substitution at the penultimate d-galactosyl residue of one of the chains with an α- d-(1→3)-linked 2-acetamido-2-deoxygalactosyl or galactosyl group did not inhibit the reactivity of the antibody. The new blood group A- and B-active, branched gangliosides are also isolated and characterized.