Abstract: A liposome assay reagent for determination of an analyte in a homogeneous immunoassay. The reagent includes a suspension of oligolamellar lipid vesicles containing encapsulated glucose-6-phosphate dehydrogenase (G6PD), at a specific activity of between about 1-15 units/.mu.mole vesicle lipid, and glucose-6-phosphate (G6P) at a concentration of at least about 5 mM. The encapsulated G6P protects the enzyme against inactivation on preparation, by reverse phase evaporation in the presence of organic solvent, and on storage as an aqueous suspension.

Abstract: A blood fluid composition for use in a complement-mediated cell lysis system. The composition includes a blood fluid, which may be either a serum source of complement, analyte-containing serum, or both, and lipid vesicles capable of reducing the extent of non-specific cell lysis produced when the blood fluid is added to lysable target cells in the system. The vesicles are present in an amount which increases the ratio of ligand-specific to non-specific cell lysis in the system at least 2-fold and preferably 4-fold or more over that achievable in the system in the absence of the vesicles.

Abstract: A viral lysis immunoassay system and method. The system includes hemolytic particles carrying non-viral, anti-analyte molecules, lysable target cells which are devoid of surface molecules capable of binding to endogenous viral surface molecules, and foreign binding molecules added to the target cells. The binding molecules, which may be either analyte molecules or analyte-related molecules attached to the target cell surfaces, function to bind the particles to the cells, to initiate cell lysis and the release of encapsulated reporter molecules from the cells. The analyte to be assayed may be one adapted to bridge the virus particles to analyte-related molecules carried on the cell surfaces, or one which competes with target-cell molecules for binding to the particle anti-analyte molecules.

Abstract: An enhanced agglutination assay method for determination of a multivalent analyte is disclosed. Analyte is added to agglutinatable particles coated with anti-analyte molecules to produce particle agglutination. The extent of agglutination is enhanced by mixing the particles and analyte with an analyte-binding reagent composed of lipid bodies. The reagent bodies act by promoting multiple analyte bridge connections between individual bridged particles and a reagent body. Also disclosed is a kit containing such particles and reagent.

Abstract: An agglutination assay reagent and method. The reagent is composed of liposomes predominantly in the 1 to 20 micron diameter size range. Each liposome has a surface array of laterally mobile ligand molecules, at a surface concentration adapted to produce reagent agglutination within about 5 minutes, when the reagent is incubated at room temperature with a multivalent ligand-binding analyte. A dye in the liposomes allows such agglutination to be visualized easily without magnification.