The identification of specific Rhesus-polypeptide-blood-group-ABH-active-glycoprotein complexes in the human red-cell membrane.
1. RhD,c and E immune complexes isolated from 3H- and 125I-surface-radiolabelled and unlabelled intact human red cells were analysed by SDS/polyacrylamide-gel electrophoresis. 2. Apparent Mr values of 31,900 for RhD polypeptide and 33,100 for Rhc,E polypeptide were obtained under both reducing and non-reducing conditions. Glycosylation of RhD,c and E polypeptides was not detected. 3. RhD,c and E immune complexes also contain a glycoprotein component. RhD glycoprotein (apparent Mr 45,000-100,000) is distinct from Rhc,E glycoprotein(s) (apparent Mr 35,000-65,000). Rh (Rhesus) glycoprotein carbohydrate moieties are susceptible to endo-beta-galactosidase digestion and carry blood-group-ABH determinants. This suggests the presence of polylactosaminoglycan-type structures. 4. Rh glycoproteins are not present in Rh immune complexes as a result of non-specific adsorption of membrane glycoproteins during the membrane-solubilization phase of immune-complex isolation because RhD immune complexes isolated from a 1:1 (v/v) mixture of Acde/cde and OcDE/cDE red cells do not contain blood-group-A-active glycoprotein. 5. Blood-group-A immune complexes isolated from group-A red cells of the appropriate Rh phenotypes contain the 31,900- and 33,100-apparent-Mr Rh polypeptides. 6. It was concluded from the above evidence that non-covalent Rh-glycoprotein-Rh-polypeptide complexes exist in the native red-cell membrane. 7. The 31,900- and 33,100-apparent-Mr Rh polypeptides are absent from blood-group-A immune complexes isolated from regulator type Rhnull cells (donor A.L.), but are replaced by a 33,800-apparent-Mr Rhnull-specific polypeptide (Rhnull polypeptide). It is suggested that Rhnull polypeptide is an aberrant product of the Rh gene complex.
D000936:Antigen-Antibody Complex; D004591:Electrophoresis, Polyacrylamide Gel; D000939:Epitopes / Q000032:analysis; D004910:Erythrocyte Membrane / Q000276:immunology*; D006023:Glycoproteins / Q000276:immunology; D006026:Glycoside Hydrolases; D006801:Humans; D008970:Molecular Weight; D010455:Peptides / Q000276:immunology*; D012204:Rh-Hr Blood-Group System / Q000276:immunology*; D001616:beta-Galactosidase
D000936:Antigen-Antibody Complex; D000939:Epitopes; D006023:Glycoproteins; D010455:Peptides; D012204:Rh-Hr Blood-Group System; C026410:Rho(D) antigen; D006026:Glycoside Hydrolases; C026093:keratan-sulfate endo-1,4-beta-galactosidase; D001616:beta-Galactosidase