title: Binding of immunoglobulin G and albumin to Streptococcus dysgalactiae.
abstract: All 24 cultures of Streptococcus dysgalactiae investigated bound 125I-IgG, 13 cultures additionally interacted with 125I-albumin. Inhibition experiments with unlabelled IgG and albumin preparations from humans and various animal species indicated the specificity of the binding sites which showed characteristics of IgG Fc-receptors of type III and albumin-receptors of type c. IgG and albumin-binding proteins could be removed from the streptococcal surface by solubilization and subsequently isolated by affinity chromatography. The isolated binding proteins of S. dysgalactiae strains C 12 and C 8 obtained from IgG and albumin sepharose precipitated with IgG in immunodiffusion reactions, and in immunoelectrophoretic studies, and they reacted, after transfer onto nitrocellulose, with 125I-IgG or 125I-albumin and vice versa. Antisera produced against IgG-binding proteins of S. dysgalactiae C 12 inhibited binding of 125I-IgG and 125I-albumin. Solubilization of binding proteins by trypsinization yielded low molecular weight fragments with 125I-IgG but not with 125I-albumin binding activities. IgG-binding proteins isolated from S. dysgalactiae C 26 reacted with 125I-IgG but not with 125I-albumin, indicating the presence of 2 groups of type III Fc-receptors among S. dysgalactiae strains.
authors.affiliation: Institut für Bakteriologie und Immunologie, Justus-Liebig-Universität, Giessen.
authors.forename: C
authors.initials: C
authors.lastname: Lämmler
authors.forename: C
authors.initials: C
authors.lastname: Frede
mesh_terms: D000418:Albumins / Q000378:metabolism*; D000818:Animals; D001426:Bacterial Proteins / Q000302:isolation & purification / Q000378:metabolism*; D001665:Binding Sites; D001667:Binding, Competitive; D015153:Blotting, Western; D002846:Chromatography, Affinity; D006801:Humans; D006863:Hydrogen-Ion Concentration; D005779:Immunodiffusion; D007122:Immunoelectrophoresis; D007074:Immunoglobulin G / Q000378:metabolism*; D008565:Membrane Proteins / Q000302:isolation & purification / Q000378:metabolism*; D013291:Streptococcus / Q000378:metabolism*
chemical_list: D000418:Albumins; D001426:Bacterial Proteins; D007074:Immunoglobulin G; D008565:Membrane Proteins