Abstract: A pharmaceutical composition suitable for administration to human beings in the prevention or treatment of immunologic disorders includes: an immune complex of an antigen and a purified antibody specific thereto, the antigen being selected from a group consisting of antigens that cause pathogenic immunologic reactions in autoimmune disease and graft rejections, and the antigen and antibody being present in a ratio whereby the antibody blocks essentially all binding sites of the antigen; and a pharmacologically acceptable carrier or diluent. The invention also provides a method of administering the composition for treatment of autoimmune disease and treatment or prevention of graft rejections.

Abstract: A pharmaceutical composition suitable for administration to human beings for suppressing the production of factor VIII inhibitor includes:an immune complex of factor VIII antigen component and factor VIII inhibitor component, the components being present in a ratio such that the inhibitor blocks essentially all relevant binding sites of the antigen; anda pharmacologically acceptable carrier or diluent. The invention also provides a method of administering the compositions to suppress the production of inhibitor to factor VIII.

Abstract: A pharmaceutical composition comprises an immune complex of an allergen and a purified antibody specific thereto, the allergen being selected from a specific subclass of antigen which causes immediate hypersensitivity that is mediated by IgE antibody, and a pharmacologically acceptable carrier or diluent. The method of using the compositions in the treatment of immediate hypersensitivity to the allergen is also described.

Abstract: A biological fluid from a first animal species (e.g. human serum) is assayed for an immunogen therein by mixing with the fluid (Ig-minus-Fc) fragments of an immunoglobulin from a second animal species (e.g. rabbit), the immunoglobulin being immunospecific to the immunogen or another component of the mixture whereby the immunogen can be determined. Interference can occur from reaction between first animal species antibodies and the said fragments, and in the method of the invention this interference is avoided or overcome, preferably by also including in the mixture different (Ig-minus-Fc) immunoglobulin fragments from the second animal species which react with said antibodies but not with said immunogen. These different fragments are preferably aggregated. The method of the invention is particularly applicable to particle agglutination assays.

Abstract: In the treatment of allergy, desensitization is effected by administering the allergen in admixture with an antibody thereto, the antibody being present in a molar excess. The antibody is preferably one raised in the patient.

Abstract: In a particle agglutination assay for an antigen (Ag), there is included in the mixture a limited amount of a substance which binds univalently with a proportion of the Ag present, that Ag which is so bound being unable then to cause agglutination of the particles. In this way, unusually large concentrations of Ag can be assayed in that a proportion of the Ag is bound to the univalent substance and the particle agglutination assay is in effect conducted on the smaller amount of Ag still remaining free in solution.

Abstract: In the immunoassay of a particular protein in a biological fluid, there is frequently interference in the assay by other proteins present in the fluid, e.g. by complement factors or antibodies in human serum. The interference so caused can be avoided by subjecting the fluid to protein-digestion, using for example an enzyme such as pepsin, as a result of which the particular protein of interest, or a fragment thereof, can be assayed without interference by the other proteins. Also, radioallergosorbent tests for particular IgE antibodies can be improved in sensitivity and accuracy, by subjecting the absorbed IgE to enzymic digestion, and then assaying a fragment thereof.

Abstract: A particle counting assay for haptens (small non-protein monovalent substances having a molecular weight below 1500) comprises mixing a liquid sample (e.g. of human origin) containing the hapten, with finely divided inert particles bearing the same hapten (or a specific analogue thereof), an agglutinator such as RF or C1q, and a measured amount of antibody, which amount is insufficient to cause agglutination of all the particles. The amount of hapten is determinable by measuring the extent of the agglutination.