Immunoassays for determining dirofilaria immitis infection using

Abstract

Competitive immunoassays, which employ idiotypic and antiidiotypic monoclonal antibody reagents, are described. These competitive immunoassays are particularly useful for the detection of low concentrations of analyte for which labeled reference analyte is difficult to obtain in quantity. Antiidiotypic monoclonal antibody reagents serves as a substitute for the labeled reference analyte. The antiidiotypic monoclonal antibody reagent exhibits a congruency of structure with one or more epitopes of the analyte or antigen. The antiidiotypic monoclonal antibody is prepared against an idiotypic monoclonal antibody, which, in turn, was prepared against the antigen or analyte. During the immunoassay, the antiidiotypic monoclonal antibody is allowed to compete with the antigen, whose concentration is being determined, for a limited number of antibody binding sites present on an idiotypic antibody, which was also prepared against the antigen or analyte. The idiotypic antibody may be either monoclonal or polyclonal, depending upon the particular immunoassay. The products of the competitive binding reactions are assessed through the use of a signal-generating label attached to either antibody. By employing standards containing known amounts of analyte, the concentration of analyte in a sample fluid may be determined. Analytes detectable by these competitive immunoassays include antigens or antibodies in aqueous fluids, including body fluids such as serum, urine, and the like. Related applications and modifications are also described.