RESUMEN
A direct binding assay for the detection of mitochondrial autoantibodies (AMA) is described. The method has been standardised to use as antigen 1 mg/ml submitochondrial particles which are absorbed on to the surface of LINBRO S-MVC-96 microtitration plates as the solid phase. 125I-labelled antihuman immunoglobulin is used as the second antibody. The sensitivity achieved is greatly increased compared with immunofluorescence and complement fixation methods, with good discrimination between AMA negative and positive sera. The assay is rapid and has the advantages of a primary binding method. Two variations of the method are described. The first is reported as a "binding index' which is calculated from the binding shown by an unknown serum at 2 dilutions, and would be suitable as a screening procedure. Binding curves of doubling dilutions of a test serum give, in addition to the binding index, a titre which is defined as that dilution at which binding returns to the level of a normal serum. This is a longer procedure and more suitable as a research method.
Asunto(s)
Autoanticuerpos/análisis , Mitocondrias Cardíacas/inmunología , Animales , Sitios de Unión , Bovinos , Enfermedad de Chagas/inmunología , Pruebas de Fijación del Complemento , Técnica del Anticuerpo Fluorescente , Humanos , Inmunoglobulinas/análisis , Inmunoglobulinas/clasificación , Técnicas Inmunológicas , Cirrosis Hepática Biliar/inmunología , Músculo Liso/inmunología , Conejos , RatasRESUMEN
A two-site antigen assay for HBsAg has been developed that employs 3 monoclonal antibodies. The antibodies were selected for their high affinity and their particular epitope specificity to establish an assay with a sensitivity for the antigen comparable with that of a conventional assay with heterologous antisera. In addition, by selecting a monoclonal antibody for use as a tracer which does not compete for antigenic binding sites with the solid-phase monoclonal antibodies, it has been possible to perform a two-site assay in a single 1 h incubation step, achieving the same degree of sensitivity. This principle of using monoclonal antibodies in a one-step assay therefore gives advantages of speed and simplicity over assays using heterologous antisera and would be applicable to a variety of antigen assays for which appropriate monoclonal antibodies are available.