Individuals lacking the Gerbich blood-group antigen have alterations in the human erythrocyte membrane sialoglycoproteins β and γ

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Abstract
Membranes from erythrocytes with a new Gerbich(Ge)-negative phenotype (Leach phenotype), as well as those from 2 other Ge-negative phenotypes, were examined. Whereas cells of the Leach phenotype apparently lack 3 minor sialoglycoproteins (.beta., .beta.1 and .gamma.), the membranes of Ge-Yus- and Ge-Yus+ erythrocytes apparently lack .beta.- and .gamma.-sialoglycoproteins but contain additional diffusely migrating components of MW 30,500-34,500 and 32,500-36,500, respectively. Immunoprecipitation experiments showed that the abnormal components of both Ge-Yus- and Ge-Yus+ erythrocytes reacted with 2 monoclonal antibodies, BRIC 4 and BRIC 10. These antibodies reacted with sialoglycoproteins .beta. and .beta.1 in normal erythrocytes. Cytoskeletal preparations from Ge-Yus- and Ge-Yus+ erythrocyte membranes contained the abnormal components. In contrast with cells of the Leach phenotype, which are elliptocytic, Ge-Yus- and Ge-Yus+ were of normal shape, despite their apparent lack of .beta.- and .gamma.-sialoglycoproteins. It seems likely that the abnormal components in these cells contribute to their normal shape. Ovalocytic erythrocytes incorporated more radioactivity in the sialoglycoprotein-.beta.1 region than normal erythrocytes after labeling by the periodate/NaB3H4 technique. Abnormal components in Ge-Yus- and Ge-Yus+ erythrocytes may result from chromosomal misalignment with unequal crossing-over at meiosis between the genes giving rise to .beta.-, .beta.1- and .gamma.-sialoglycoproteins.