title: Serological and immunochemical characterization of anti-PP1Pk (anti-Tja) antibodies in blood group little p individuals. Blood group A type 4 recognition due to internal binding.
abstract: Serum samples from 13 blood group little p individuals were tested by radioimmunoassay for their IgG antibody subclass distribution against the P, P1 and Pk antigens. There was no uniform subclass distribution pattern, although all but one had IgG3 antibodies against all the P system antigens tested. Studies were performed adsorbing anti-Tja serum sequentially to columns with synthetic carbohydrate antigenic determinants within the P system coupled to silica beads (SynsorbsR). The effect on agglutinin and indirect antiglobulin titers was determined after adsorption to SynsorbsR with different P-system antigens (P1, Pk, P). Adsorption to all the three SynsorbsR was needed to eliminate or strongly reduce antibody titers. The effect on IgM, IgG, IgA as well as IgG subclass antibody binding to P, P1 and Pk antigens was also determined by radioimmunoassay and chromatogram binding assay. Anti-PP1Pk antibodies from a little p woman with repeated abortions were shown to bind to glycosphingolipid antigens prepared from one of the aborted placentae using a chromatogram binding assay. This binding was eliminated by serum adsorption to SynsorbsR with P1, Pk and P carbohydrates. Anti-PP1Pk antibodies were also shown to bind to extended structures in the globoseries, i.e. globopentaosylceramide, globohexaosylceramide (globo-H) and globoheptaosylceramide (globo-A). This binding is most probably due to antibodies recognizing internal sequences in the carbohydrate chain. Attempts were made to visualize the binding epitope of the antibodies by computer molecular modelling.
authors.affiliation: Regional Bood Center, Sahlgren's Hospital, Göteborg, Sweden.
authors.forename: L
authors.initials: L
authors.lastname: Rydberg
authors.forename: B
authors.initials: B
authors.lastname: Cedergren
authors.forename: M E
authors.initials: ME
authors.lastname: Breimer
authors.forename: K
authors.initials: K
authors.lastname: Lindström
authors.forename: P G
authors.initials: PG
authors.lastname: Nyholm
authors.forename: B E
authors.initials: BE
authors.lastname: Samuelsson
mesh_terms: D000328:Adult; D000368:Aged; D000373:Agglutinins / Q000276:immunology; D000888:Antibodies, Anti-Idiotypic / Q000276:immunology; D002240:Carbohydrate Sequence; D002851:Chromatography, High Pressure Liquid; D005260:Female; D006017:Glycolipids / Q000276:immunology; D006801:Humans; D007070:Immunoglobulin A / Q000276:immunology; D007074:Immunoglobulin G / Q000032:analysis* / Q000276:immunology; D007075:Immunoglobulin M / Q000276:immunology; D007518:Isoantibodies / Q000032:analysis; D008297:Male; D008875:Middle Aged; D008958:Models, Molecular; D008968:Molecular Conformation; D008969:Molecular Sequence Data; D010127:P Blood-Group System / Q000276:immunology*; D011863:Radioimmunoassay
chemical_list: D000373:Agglutinins; D000888:Antibodies, Anti-Idiotypic; D006017:Glycolipids; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D007518:Isoantibodies; D010127:P Blood-Group System