Summary
We report the localization of A, B blood group determinants on intrinsic glycoproteins
using anti-A, B IgG antibodies. By radioimmunoprecipitation, anti-A and anti-B precipitated
three bands with apparent molecular masses in sodium dodecylsulphate- polyacrylamide
gel electrophoresis (SDS-PAGE) of 159, ~ 120 and 85 kDa under non-reduced conditions
and 145, ~ 126 and 97 kDa under reduced conditions. In two-dimensional gel electrophoresis
(isoelectric focussing/SDS-PAGE) these three bands could be resolved into six spots
and fulfilled previously defined citeria for platelet membrane glycoprotein complexes
Ia/IIa, Ic’IIIa, Ib/IX and IIb/IIIa. The results were supported by data obtained by
an assay employing antibody-specific immobilizatisn of platelet antigens (MAIPA).
By this technique, blood group A, B determinants were shown to be immobilized by monoclonal
antibodies specific for GPIa, Ic’, IX, IIb/IIIa and strongly by mab specific for GPIIa,
but not by mab specific for HLA class I molecules.
The more precise localization on platelet glycoproteins was achieved by immunoblotting
technique by which blood group A determinants could be assigned to GPs IIa, IIIa and
Ib.