title: Quantitation of IgE antibodies by radioimmunoassay in the presence of high concentrations of non-IgE antibodies of the same specificity.
abstract: Radioimmunoassays for mouse IgE antibodies, based on adherence to an antigen-coated surface, are precise and sensitive, but errors can be introduced by the presence of relatively high concentrations of non-IgE antibodies of the same specificity. Such errors are caused by competition for the limited number of antigenic determinants on the antigen-coated surface. In this paper we explore further the quantitative aspects of the 'competition effect'. An easily applied method is described, based on preferential precipitation of non-IgE antibodies by ammonium sulfate, that permits analysis of IgE antibodies in the presence of large amounts of non-IgE antibodies (that are principally IgG). For IgE anti-Ar, the maximum permissible ratio is extended from approximately 1500:1 to at least 40,000:1. We have also determined the effect of IgG antibodies or whole mouse serum on PCA reactions of mouse IgE antibodies, carried out in rats.
mesh_terms: D000645:Ammonium Sulfate; D000818:Animals; D000918:Antibody Specificity; D011232:Chemical Precipitation; D007073:Immunoglobulin E / Q000032:analysis*; D007074:Immunoglobulin G / Q000032:analysis; D051379:Mice; D008815:Mice, Inbred Strains; D011863:Radioimmunoassay; D010132:p-Azobenzenearsonate / Q000276:immunology
chemical_list: D007074:Immunoglobulin G; D007073:Immunoglobulin E; D010132:p-Azobenzenearsonate; D000645:Ammonium Sulfate