Characterization of blood group ABO(H)-active gangliosides in type AB erythrocytes and structural analysis of type A-active ganglioside variants in type A human erythrocytes.
Several monosialogangliosides containing the type A-active epitope have been detected in type A erythrocytes on immunological analysis with a monoclonal antibody, and three of them were purified by repeated silica bead column chromatography and by scraping from the TLC plate. Two of these A-active gangliosides were characterized by methylation analysis by GC/MS, negative SIMS, MALDI-TOF/MS, proton nuclear magnetic resonance spectroscopy, and immunological assays, and their structures were concluded to be as follows. A-active ganglioside I:A-active ganglioside II:The reactivity of the purified gangliosides to the anti-A monoclonal antibodies (mAbs) exhibited enhancement after removal of the sialic acid. Therefore, the sialic residue has been shown to inhibit the binding to the terminal A-active epitope through the formation of an immune complex. To confirm the presence of A- (including S-A-I, -II and -III) and B-active gangliosides, the reactivity of anti-A and -B mAbs were investigated using total gangliosides from type A, -B and -AB erythrocytes on TLC plate. The results were that the gangliosides from types A and AB showed positive reaction to anti-A mAbs, whereas in the anti-B mAbs binding the gangliosides from types B and AB were positive. Thus, it revealed that A-active gangliosides were present in type A and -AB, and B-active gangliosides in types B and AB. As there was no difference in respective gangliosides on type AB erythrocytes of 22 individuals, both A- and B-active gangliosides are equally present in type AB erythrocytes. The biological significance of these A- and B-active ganglioside variants remains vague at present. As these molecules exhibit different reactivities to the anti-A mAbs, it is very likely that they can regulate the antigenicity of the A-epitope on the cell surface.
Kushi
Y
Y
Department of Biochemisry, Faculty of Medicine, Tokyo Medical and Dental University, Japan. y.kushi.mmch@med.tmd.ac.jp
Shimizu
M
M
Watanabe
K
K
Kasama
T
T
Watarai
S
S
Ariga
T
T
Handa
S
S
D000017:ABO Blood-Group System / Q000737:chemistry*; D000818:Animals; D000911:Antibodies, Monoclonal; D002240:Carbohydrate Sequence; D002852:Chromatography, Ion Exchange; D000939:Epitopes / Q000737:chemistry; D004912:Erythrocytes / Q000737:chemistry* / Q000276:immunology; D005732:Gangliosides / Q000097:blood* / Q000737:chemistry* / Q000276:immunology; D006801:Humans; D066298:In Vitro Techniques; D051379:Mice; D008969:Molecular Sequence Data; D019158:N-Acetylneuraminic Acid / Q000737:chemistry
D000017:ABO Blood-Group System; D000911:Antibodies, Monoclonal; D000939:Epitopes; D005732:Gangliosides; D019158:N-Acetylneuraminic Acid