title: Restriction in IgM expression--VI. Affinity analysis of monoclonal anti-dansyl antibodies.
abstract: Affinity restriction in the IgM response to the 5-dimethylaminonaphthalene-1-sulfonyl (dansyl) group was studied with 56 monoclonal IgG and IgM affinity-purified antibodies. These were generated by immunization with dansyl-Ficoll or dansyl-B gamma G. Association constants for N epsilon-dansyl-lysine were determined by fluorescence titration based on resonance energy transfer. The antibodies were also characterized with respect to the emission maximum of the antibody-ligand complex. The distribution of binding constants covered a 100,000-fold range, demonstrating thereby a restriction in IgM affinity relative to IgG affinity. In the secondary response the IgG affinity exhibited a ceiling of about 1 X 10(10) M-1, a value in accord with the size and hydrophobic nature of the dansyl group. In the case of IgM, with one exception, the value of 1 X 10(7) M-1 was not exceeded with IgM antibodies isolated from 28 hybridomas. This system, therefore, provides further evidence for the restriction in expression of IgM as a general feature of the immune response.
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000915:Antibody Affinity; D000937:Antigen-Antibody Reactions; D003619:Dansyl Compounds / Q000276:immunology*; D006825:Hybridomas / Q000276:immunology; D007074:Immunoglobulin G / Q000276:immunology; D007075:Immunoglobulin M / Q000096:biosynthesis* / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D013050:Spectrometry, Fluorescence
chemical_list: D000911:Antibodies, Monoclonal; D003619:Dansyl Compounds; D007074:Immunoglobulin G; D007075:Immunoglobulin M