Abstract: Lipid vesicles, labelled with encapsulated reporter compositions and bound to antibodies comprise a new class of immunoreagent, useful in immunoassays for ligands.

Abstract: Two-site immunometric assays for multideterminant antigens are described in which the antigen is reacted with an immobilized monoclonal antibody directed against one antigen determinant and a second monoclonal antibody that is directed against a distinct antigenic determinant and is of a different class or subclass than the immobilized monoclonal antibody. The second monoclonal antibody is labeled in direct versions of the assay and is reacted with a labeled antibody against it in indirect versions of the assay. The immobilizing medium and classes (subclasses) of the antibodies may be selected so as to reduce the likelihood of nonspecific binding enhance sensitivity and/or permit signal amplification.

Abstract: A method and kit for determining the presence of a polyvalent ligand in an aqueous fluid. The method involves incubating the fluid with an immobilized antibody to the ligand to form an immobilized ligand-antibody complex, then incubating the immobilized ligand-antibody complex with a solution of a soluble complex of a second antibody (to the ligand) and a labeled binding protein, such as protein A. The labeled binding protein is specifically bound to the Fc portion of the second antibody. The unbound second antibody and labeled binding protein are washed from the immobilized complex, and the presence of bound labeled binding protein is determined as a measure of the concentration of the ligand in the aqueous fluid.

Abstract: An improvement in assaying methods involving biospecific affinity reactions, in which there are used from 2 to 4 reactants, one of which, reactant (I), is labelled with at least one analytically indicatable atom or group and is soluble in the aqueous liquid in which the biospecific affinity reaction is carried out, the reactants forming, by means of biospecific reactions, a conjugate in which labelled reactant (I) is incorporated; and in which assaying methods the analytically indicatable atom or group is assayed in the conjugate and/or in labelled reactant (I), which is not bound to the conjugate. The conjugate that has been formed or labelled reactant (I) not bound to the conjugate is bound covalently to an insoluble carrier or to an insolubilizable carrier, which latter carrier is made insoluble after the covalent binding has been carried out, whereafter the assay of the analytically indicatable atom or group is carried out.

Abstract: A process for determining the presence of an antigen or antibody in a sample wherein said antigen or antibody exists in the form of an immune complex which comprises:A. contacting the immune complex originating from the sample suspected of containing immune complex with a dissociating buffer whereby said immune complex, if present, is dissociated into antigen and antibody;B. contacting a solid support which binds proteins with said dissociating buffer suspected of containing antigen or antibody and removing said buffer;C. washing said solid support;D. adding protein to fill unoccupied sites on said solid support;E. adding radioactively labeled or enzyme labeled antibody or antigen to said solid support, said labeled antibody or antigen corresponding to antigen or antibody on said solid support, incubating the resultant mass and washing the same;F. measuring the radioactivity or enzymatic activity associated with the solid support.

Abstract: An improved radioimmunoassay for the determination of cyclic nucleotides in body fluids which comprises adding a source of divalent cation prior to assay minimizes the effects of both endogenous calcium ion and EDTA used as an anticoagulant in blood plasma samples.

Abstract: An improved method for the preparation of .sup.125 I-labelled Protein A (.sup.125 I PA) of high specific and functional activity. .sup.125 I PA has been used in combination with purified rabbit IgG (immunoglobulin G) bound to a solid support to develop a competitive binding assay capable of detecting Protein A or human, rabbit and guinea pig IgG at the nanogram level. Additionally, .sup.125 I PA may be used to detect methotrexate, leucovorin and similar substances..sup.125 I PA has also been used to detect IgG anti-Forssman antibody bound to sheep erythrocytes and to line-1 and line-10 tumor cells and as an indirect assay for tumor associated antigen in the ascitic fluid of tumor-bearing guinea pigs.Additionally, an improved method of preparation of iodination of Protein A is utilized. This procedure used the Bolton-Hunter (1973) reagent of radioactive iodine in benzene which carrier is evaporated.

Abstract: A diagnostic reagent for immunological tests for detecting or measuring a component in human or animal body fluids or for labeling cells, including immunochemicals immobilized on a particulate carrier characterized in that fine particles having an average diameter in the range of about 0.03 to about 10 .mu.m and comprising a cross-linked polymer having a repeating unit represented by the general formula ##STR1## wherein R stands for hydrogen or a methyl group, are used as the particulate carrier.

Abstract: In the immunoassay of antigens in liquids, a reaction mixture is formed containing the liquid under assay, labelled antigen, and a mixed binding reagent which contains an antigen-binding site and a label-binding site, the two sites being spaced apart in the reagent so that a single molecule of labelled antigen cannot bind to both sites. The label is one whose activity is changed upon binding to a label-binding site, and the amount of antigen in the original liquid sample is determined by measuring the activity of the label in the reaction mixture. A preferred label is a fluorophore. The mixed binding reagent preferably consists of two antibodies linked together.

Abstract: A stabilized radioimmunoassay product consisting of an antibody protein-bound to the cell wall of a selected bacterium whereby the antibody is irreversibly bound to the protein and remains specific for the antigen against which it was developed. The radioimmunoassay product is also characterized by the fact that the resultant complete product includes a phase of serum protein treatment to isolate the protein sites or other sites of nonspecific reactivity with the labelled antigen such that the non-specific binding of labelled antigen is significantly reduced. Also within the contemplation of the invention is the method of manufacturing the radioimmunoassay product which includes the initial phase of protein binding of the antibody to the selected bacterium and the subsequent serum treatment to isolate previously unutilized protein sites such that when said sites are subsequently exposed to labelled antigen it will be rejected.