title: Methodological approaches to antigen identification in soluble immune complexes; A model study.
abstract: The usefulness of different techniques for identification of immune complex-(IC) bound antigen(s) was investigated in two Ab-Ag model systems. The following approaches were used: 1) determination of IC-activity before and after removal of IC by adsorption to antibody-specific solid phase systems. 2) analysis of PEG-insoluble IC by reference line-rocket immunoelectrophoresis and 3) reprecipitation of PEG-insoluble IC in the presence of 125I-labelled antibody to suspected antigens and subsequent analysis of the distribution of the radioactivity. This latter approach, the use of a double PEG precipitation immunoradiometric assay, was found most useful and simple for identification of antigen(s) contained in soluble IC. The technique is most sensitive in demonstrating IC-bound antigen(s) when the IC are formed in slight to moderate antigen excess.
mesh_terms: D000327:Adsorption; D000936:Antigen-Antibody Complex / Q000032:analysis*; D000942:Antigens, Bacterial / Q000032:analysis*; D000939:Epitopes / Q000032:analysis; D006801:Humans; D007122:Immunoelectrophoresis; D007158:Immunologic Techniques; D011863:Radioimmunoassay
chemical_list: D000936:Antigen-Antibody Complex; D000942:Antigens, Bacterial; D000939:Epitopes