title: Inhibition of the Prausnitz-Küstner reaction by an immunoglobulin epsilon-chain fragment synthesized in E. coli.
abstract: The Prausnitz-Küstner (P-K) reaction is a sensitive test for the presence and activity in the skin of immunoglobulin E, an important class of immunoglobulin mediating allergic reactions. A fragment of the human myeloma ND epsilon-chain gene, encoding the second, third and fourth domains of the IgE constant region (C epsilon 2-4) was assessed here for its ability to inhibit the P-K reaction in vivo. Injection of the fragment in skin sites of healthy human adults prevented subsequent sensitization with serum containing IgE antibody to ragweed antigen. Inhibition of the P-K reaction required a 200-fold molar excess of the C epsilon fragment over the IgE present in the sensitizing serum. The efficacy of the C epsilon fragment in inhibiting the P-K reaction compared favourably with that of natural myeloma IgE (PS) in terms of both blocking concentrations and duration of the blocking effect. The inhibition of the P-K reaction by C epsilon 2-4 fragments was specific and probably caused by the saturation of IgE receptors on mast cells by the recombinant gene product.
mesh_terms: D004926:Escherichia coli / Q000235:genetics*; D005796:Genes; D006801:Humans; D007118:Immunoassay; D007127:Immunoglobulin Constant Regions / Q000235:genetics; D007073:Immunoglobulin E / Q000032:analysis*; D007143:Immunoglobulin Heavy Chains / Q000235:genetics*; D007139:Immunoglobulin epsilon-Chains / Q000032:analysis / Q000235:genetics*; D009101:Multiple Myeloma / Q000235:genetics / Q000276:immunology; D012867:Skin / Q000276:immunology*
chemical_list: D007127:Immunoglobulin Constant Regions; D007143:Immunoglobulin Heavy Chains; D007139:Immunoglobulin epsilon-Chains; D007073:Immunoglobulin E