title: Cooperative binding of two antibodies to independent antigens by an Fc-dependent mechanism.
abstract: Binding of a murine N-acetylglucosamine (GlcNAc)-specific IgG3 monoclonal antibody to a solid phase expressing GlcNAc determinants and phosphocholine (PC) determinants is enhanced by IgG3, but not IgG2b, PC-specific monoclonal antibody. The cooperative binding requires an intact Fc region on the GlcNAc-specific monoclonal antibody and is hypothesized to result from Fc-Fc association. Although the in vivo relevance of this phenomenon requires further study, intermolecular cooperativity in binding of antibody to multivalent antigens, such as bacterial cell wall antigens, could represent an adaptive mechanism for antibodies expressing low intrinsic affinities for highly repeated epitopes. Furthermore, the ability of antibodies of distinct specificity to participate in cooperative binding offers, at least in principle, new approaches to optimizing antibody targeting.
authors.affiliation: Institute of Pathology, Case Western Reserve University, Cleveland, Ohio 44106.
authors.forename: N S
authors.initials: NS
authors.lastname: Greenspan
authors.forename: D A
authors.initials: DA
authors.lastname: Dacek
authors.forename: L J
authors.initials: LJ
authors.lastname: Cooper
mesh_terms: D000117:Acetylglucosamine / Q000276:immunology*; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D000941:Antigens / Q000276:immunology*; D001666:Binding Sites, Antibody; D005944:Glucosamine / Q000031:analogs & derivatives*; D007141:Immunoglobulin Fc Fragments / Q000276:immunology*; D007074:Immunoglobulin G / Q000276:immunology*; D051379:Mice; D010767:Phosphorylcholine / Q000276:immunology; D011135:Polysaccharides, Bacterial / Q000276:immunology*; D013296:Streptococcus pneumoniae / Q000276:immunology; D013297:Streptococcus pyogenes / Q000276:immunology
chemical_list: D000911:Antibodies, Monoclonal; D000941:Antigens; D007141:Immunoglobulin Fc Fragments; D007074:Immunoglobulin G; D011135:Polysaccharides, Bacterial; C044260:streptococcal group A cell wall carbohydrate; D010767:Phosphorylcholine; D005944:Glucosamine; D000117:Acetylglucosamine