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Evidence That the Human Blood Group Antigens Gy a and Hy Are Carried on a Novel Glycosylphosphatidylinositol‐Linked Erythrocyte Membrane Glycoprotein
Author(s) -
Spring F. A.,
Reid M.E.
Publication year - 1991
Publication title -
vox sanguinis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.68
H-Index - 83
eISSN - 1423-0410
pISSN - 0042-9007
DOI - 10.1111/j.1423-0410.1991.tb00871.x
Subject(s) - glycoprotein , membrane glycoproteins , antigen , pronase , red blood cell , biochemistry , microbiology and biotechnology , trypsin , p glycoprotein , biology , immunoprecipitation , chemistry , enzyme , immunology , gene , multiple drug resistance , antibiotics
. Immunoblotting under non‐reducing conditions with purified human anti‐Gy a and anti‐Hy locates both antigens to an erythrocyte membrane glycoprotein of apparent M r 46,750–57,500. The antigens are destroyed on intact red cells by the enzymes pronase, trypsin and chymotrypsin, and by treatment with reducing agents. Immunoblotting with anti‐Gy a and anti‐Hy to membranes prepared from red cells pre‐treated with an Endo F preparation caused a mean reduction in apparent M r of the glycoprotein by 11kDa at the leading and trailing edges, when compared with control membranes. These results suggest that the glycoprotein has one or more complex N‐glycans that are not completely sensitive to Endo F digestion on intact cells. The majority of Gy a /Hy‐active molecules are not tightly associated with the red cell membrane skeleton. A gross reduction in reactivity with anti‐Gy a and anti‐Hy by immunoblotting was observed in red cell membranes from patients with paroxysmal nocturnal haemoglobinuria, suggesting a possible membrane linkage via glycosylphosphatidylinositol for the glycoprotein that carries the Gy a and Hy antigens. Immunoprecipitation of the glycoprotein by anti‐Gy a showed that the protein migrates faster under reducing conditions (M r 45,000–54,000). A putative dimer was also evident in the precipitates. The glycoprotein was demonstrated to be distinct from lymphocytefunction‐associated antigen‐3 (CD58), the LW ab ‐active glycoprotein, the Fy a ‐active glycoprotein, the Ok a ‐active glycoprotein and the BRIC 125 glycoprotein (CD47).