Altered Membrane Sialoglycoproteins in Human Erythrocytes Lacking the Gerbich Blood Group Antigens

Abstract

The sialoglycoproteins (glycophorins) in human red cell membranes of rare individuals lacking totally (Ge-1,-2,-3 phenotype) or partially (Ge-1,-2,3 phenotype) the Gerbich (Ge) blood group antigens and 2 Ge-1,-2,-3 heterozygotes were studied by dodecyl sulfate polyacrylamide gel electrophoretic techniques. Two sialoglycoproteins (components D and E) were not detectable in the membranes from the homozygotes and found to be decreased by about 50% in those from the heterozygotes. Ge-1,-2,-3 and Ge-1,-2,3 cells were found to contain a new component (mol. masses about 29 and 30 [kdalton], respectively) possibly representing a D/E hybrid molecule. This sialoglycoprotein was not detectable in membranes from the Ge-1,-2,-3 heterozygotes, suggesting that the Ge-1,-2,-3 phenotype may be caused by at least 2 different alleles at the Ge blood group antigen locus. Hemagglutination or hemagglutination inhibition tests involving anti-Ge1,2,3 and -Ge1,2 as well as native and enzyme-treated normal red cells (phenotype Ge1,2,3) or membrane and sialoglycoprotein fractions from normal erythrocytes indicate that the receptors of these sera are located with the glycosylated domain(s) of the D and/or E sialoglycoprotein(s). Apparently, the Ge locus encodes the polypeptide sequences of the D and E sialoglycoproteins.