title: Heterogeneity of anti-U demonstrable by the use of papain-treated red cells.
abstract: When red cells (RBCs) are treated with papain, one form of the U antigen, which we have named UPS (U papain-sensitive), is almost completely removed or denatured. A second form, UPR (U papain-resistant), remains unaltered on the treated RBCs. Tests on 42 examples of anti-U showed that two contained only anti-UPS, 19 contained only -UPR, and 21 contained separable -UPS and -UPR. In those sera containing both antibodies, anti-UPR was always the stronger of the two. These findings suggest 1) that UPS is located on the Ss sialoglycoprotein (glycophorin B) at a position distal to a papain-sensitive site or that the cleavage point is within the portion of the SGP that comprises UPS, and 2) that UPR is located between the papain-sensitive site and the RBC membrane. The UPS determinant was not denatured by neuraminidase, L-cysteine, trypsin, ficin, or alpha-chymotrypsin, and it was only partially denatured by pronase. The finding that RBCs treated with para-chloromercuribenzoic acid or para-chloromercuriphenyl sulfonic acid did not react with anti-UPR but did continue to react with anti-UPS suggests that the in situ configuration of UPR, but not UPS, is dependent on the presence of one or more disulfide bonds. RBCs of the S-s-U+(weak) phenotype were shown to carry markedly reduced amounts of both UPS and UPR.
authors.affiliation: American Red Cross Blood Services, South Florida Region, Miami.
authors.forename: P D
authors.initials: PD
authors.lastname: Issitt
authors.forename: W L
authors.initials: WL
authors.lastname: Marsh
authors.forename: M R
authors.initials: MR
authors.lastname: Wren
authors.forename: M
authors.initials: M
authors.lastname: Theuriere
authors.forename: K
authors.initials: K
authors.lastname: Mueller
mesh_terms: D000327:Adsorption; D000328:Adult; D001789:Blood Group Antigens / Q000276:immunology*; D001788:Blood Grouping and Crossmatching; D003298:Coombs Test; D006801:Humans; D007202:Indicators and Reagents; D007518:Isoantibodies / Q000032:analysis* / Q000235:genetics; D008951:MNSs Blood-Group System / Q000276:immunology; D008297:Male; D010206:Papain; D010641:Phenotype; D012795:Sialoglycoproteins / Q000276:immunology
chemical_list: D001789:Blood Group Antigens; D007202:Indicators and Reagents; D007518:Isoantibodies; D008951:MNSs Blood-Group System; D012795:Sialoglycoproteins; D010206:Papain