Role of A and B blood group antigens in the expression of adhesive activity of von Willebrand factor.
ABO (H) blood group antigens are covalently linked to the oligosaccharide side-chains of von Willebrand factor (VWF). In this study, we investigated the role of the A and B antigens in the expression of VWF adhesive activity. VWF of type A, B or O was purified from fresh frozen plasma. Presence of A or B antigen on the VWF was confirmed by enzyme-linked immunosorbent assay (ELISA) and by immunoblotting with monoclonal anti-A or anti-B. The A or B antigen was also detected in the 48/52-kDa fragment of the respective VWF after trypsin digestion. Removal of A antigen with alpha-N-acetylgalactosaminidase or B antigen with alpha-galactosidase did not affect its multimer size or antigenic level, but decreased the ristocetin cofactor (RCoF) activity of the respective VWF by 33-39% (P < 0.01-0.002). Removal of A or B antigen from VWF did not affect the binding of the VWF to immobilized type III collagen. A and B antigens were not detected in platelet VWF. These results indicate that AB structures play a role in platelet aggregating activity of VWF.
Department of Pathology, University Hospitals of Cleveland, Case Western Reserve University, Cleveland, OH 44106, USA. ravi.sarode@uhhs.com
R
R
Sarode
J
J
Goldstein
I I
II
Sussman
R L
RL
Nagel
H M
HM
Tsai
D000017:ABO Blood-Group System; D003094:Collagen / Q000378:metabolism; D006801:Humans; D007519:Isoantigens / Q000502:physiology*; D010974:Platelet Aggregation / Q000276:immunology*; D011485:Protein Binding; D012310:Ristocetin / Q000378:metabolism*; D014841:von Willebrand Factor / Q000378:metabolism*
D000017:ABO Blood-Group System; D007519:Isoantigens; D014841:von Willebrand Factor; D012310:Ristocetin; D003094:Collagen