title: A restricted human antitetanus clonotype shares idiotypic cross-reactivity with tetanus antibodies from most human donors and rabbits: reactivity with antibodies of widely differing electrophoretic mobility.
abstract: Antitetanus antibodies from each of 20 hyperimmunized human donors were isolated on a tetanus immunoadsorbent, eluted with acidic buffer, and examined by isoelectric focusing (IEF). There was electrophoretic restriction, as determined by IEF, in the IgG of only 20% of the purified antibodies studied. The remaining 80% showed a more diffuse polyclonal spectrotype. Several IEF bands from the most electrophoretically restricted sample were isolated and used to immunize rabbits. Virtually every IgG-IEF band in the antitetanus antibodies of the original donor shared idiotypic cross-reactivity as detected by one or more of the three rabbit anti-Id reagents, even though major qualitative differences in binding from one rabbit anti-Id reagent to another were noted. Antitetanus antibodies of each of the 20 donors were separated by IEF and transferred to a nitrocellulose membrane. By using a sensitive and specific ELISA detection method, cross-reactivity was detected with the rabbit anti-Id reagents in 1 to 50% of the antitetanus antibodies of individual donors. This cross-reactivity was greater than 10% in 15 of the 19 antisera studied. In addition, these cross-reactive antibodies had very different electrophoretic mobility. Binding of the rabbit anti-Id reagents to the tetanus antibodies was almost completely blocked by pretreatment with soluble tetanus toxoid antigen. This idiotypic cross-reactivity with antibodies of different electrophoretic mobility from the same and unrelated donors suggests sharing among these antibodies of one or more of the germ-line DNA-encoded hypervariable regions present in the antibody-combining site.
mesh_terms: D000818:Animals; D000888:Antibodies, Anti-Idiotypic / Q000032:analysis* / Q000096:biosynthesis; D000907:Antibodies, Bacterial / Q000008:administration & dosage / Q000032:analysis* / Q000235:genetics; D000942:Antigens, Bacterial / Q000276:immunology; D001666:Binding Sites, Antibody; D001667:Binding, Competitive; D003429:Cross Reactions; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis / Q000378:metabolism; D007130:Immunoglobulin Idiotypes / Q000032:analysis / Q000235:genetics / Q000276:immunology*; D007525:Isoelectric Focusing; D011817:Rabbits; D013745:Tetanus Toxoid / Q000276:immunology*
chemical_list: D000888:Antibodies, Anti-Idiotypic; D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D007074:Immunoglobulin G; D007130:Immunoglobulin Idiotypes; D013745:Tetanus Toxoid