Human platelets express gangliosides with LKE activity and ABH blood group activity.
BACKGROUND
Platelets express several neutral glycosphingolipids with ABH and P blood group activity that may play a role in infectious, autoimmune, and alloimmune thrombocytopenia. In RBCs, sialylated glycosphingolipids or gangliosides with blood group activity have also been reported. To determine whether similar antigens are expressed by platelets, the total platelet ganglioside fraction was isolated and screened for blood-group-active glycosphingolipids.


METHODS
Platelet gangliosides were isolated by organic extraction, base hydrolysis, anion exchange, silicic acid, and high-performance liquid chromatography. Gangliosides were identified and characterized by high-performance thin-layer chromatography-immunostaining with blood group-specific MoAbs and glycosidase digestion.


RESULTS
Group A, but not group O, platelets express five gangliosides with group A activity. Of five A MoAbs and lectins examined, only MoAbs Birma-1 and MHO4 recognized all five sialyl A bands. The sialyl A bands were sensitive to endoglycoceramidase and neuraminidase. One sialyl A band may represent a branched ganglioside with sialyl-I and group A activity. Platelets also express an LKE-active ganglioside consistent with sialyl-galactosylgloboside.


CONCLUSIONS
In addition to sialyl-iI and sialyl-Le(x) gangliosides, group A platelets express gangliosides with LKE activity and group A activity. Like RBCs, group A-active gangliosides may act as alloantigens and autoantigens to naturally occurring isohemagglutinins.
Cooling
L L
LL
Department of Pathology, State University of New York Upstate Medical University, Syracuse, New York, USA. lcooling@med.umich.edu
Zhang
D
D
Koerner
T A
TA
D000017:ABO Blood-Group System / Q000096:biosynthesis / Q000276:immunology*; D016824:Antigens, Human Platelet / Q000276:immunology; D001792:Blood Platelets / Q000276:immunology*; D005732:Gangliosides / Q000096:biosynthesis / Q000276:immunology*; D006028:Glycosphingolipids / Q000096:biosynthesis / Q000276:immunology*; D006801:Humans; D055746:Stage-Specific Embryonic Antigens
D000017:ABO Blood-Group System; D016824:Antigens, Human Platelet; D005732:Gangliosides; D006028:Glycosphingolipids; D055746:Stage-Specific Embryonic Antigens; C066584:stage-specific embryonic antigen-4