Hybrid sialoglycoprotein content of St(a+) red cells.
St(a+) red cells contain a ficin-resistant hybrid sialoglycoprotein (SGP) consisting of the amino terminus of Ss sialoglycoprotein (Ss SGP) and the carboxyl terminus of MN sialoglycoprotein (MN SGP). Ficin-modified St(a+) but not St(a-) red cells were agglutinated by monoclonal antibodies NN5 (anti-N) and 31 (detecting a sialic acid-dependent determinant on the SGPs). SDS-polyacrylamide gel electrophoresis showed three periodic acid-Schiff-staining protein bands in ficin-modified St(a+) but not St(a-) red cell-membranes; these bands bound monoclonal antibodies NN5 and 31 on Western blots. Using Scatchard analysis of 125I-NN5 IgG binding to M+N- red cells, estimates were obtained of 25,000 Ss SGP molecules per red cell per s allele, 33,000 Ss SGP molecules per red cell per S allele, and 75,000 hybrid SGP molecules per red cell per hybrid allele. These results are consistent with the expression of the hybrid SGP gene at a level intermediate between the MN SGP gene and the Ss SGP gene. Monoclonal antibodies NN5 and 31 may be useful in screening ficin-treated red cells for hybrid SGP variants.
Rearden
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Department of Pathology, University of California, San Diego.
D000911:Antibodies, Monoclonal; D000940:Antigenic Variation; D003101:Collodion; D004591:Electrophoresis, Polyacrylamide Gel; D006386:Hemagglutination Tests; D006801:Humans; D007124:Immunoenzyme Techniques; D008951:MNSs Blood-Group System / Q000235:genetics* / Q000276:immunology; D008562:Membrane Glycoproteins / Q000097:blood* / Q000235:genetics / Q000302:isolation & purification; D010209:Paper; D010641:Phenotype; D011863:Radioimmunoassay; D012795:Sialoglycoproteins / Q000097:blood* / Q000235:genetics / Q000302:isolation & purification
D000911:Antibodies, Monoclonal; D008951:MNSs Blood-Group System; D008562:Membrane Glycoproteins; D012795:Sialoglycoproteins; D003101:Collodion