Abstract: Method for discriminating unstained cells from stained cells in a heterogeneous population. Specified cell types are stained with an absorbing stain and all cells are passed through the class of flow cytometry instrumentation employing focused collimated light sources. Detection of low angle and wide angle light scatter permits differentiation between the cell types on the basis that cells stained with an absorbing stain produce comparatively less low angle light scatter and comparatively more wide angle light scatter than do unstained cells.

Abstract: Methods for determining the presence of antigens or antibodies in an aqueous sample or presence of antigens on the surface of cells. A preferred embodiment employs fluorescent antigens which compete with the sample antigens for antibody binding sites. The antibodies are deposited on a support surface means in alternating patterns. The surface means and fluorescence detector are translocated with respect to each other and a signal generated by the detection of the repeating pattern of fluorescence. The signal is analyzed by means of a gated integrator responsive to a gate track control means also located on the surface means. Immunoassay methods having increased sensitivity are thereby obtained.

Abstract: A particle washing system and method of use provides for the placement of the fluid containing the desired particles within an inner tube having near the bottom thereof an orifice plugged with a material for sealing the particulate containing fluid from a wash fluid under forces substantially equal to 1G. The inner tube is positioned within an outer tube which contains a wash fluid having a density at least equal to that of the particle containing solution but less than that of the particles. Application of centrifugal force, substantially greater than 1G, and directed toward the bottom of the outer tube, causes the sealing material to be dislodged thereby permitting the particles to move through the orifice and through the outer solution. Thus the particles are collected from the inner solution, washed by the outer solution, and pelleted at the bottom of the outer tube.

Abstract: A sample having a mixture of unknown stained cells and known cells having different staining characteristics is analyzed rapidly, a cell at a time, in a flow cytometry system having a sample stream dimension in the range of expected cell dimensions. The cells are illuminated with focused illumination and fluorescence is detected and related to the number of cells. The resulting histogram of the mixture sample may be analyzed by counting the cells in a controlled population below a relatively low threshold value of fluorescence intensity to form a first fraction and relating this fraction to the fraction of cells in the sample mixture below the threshold value of fluorescence intensity to determine the number of unknown cells in the sample mixture.

Abstract: The method assesses the level of general and specific cellular immunocompetence by measuring the responses of individuals to antigens in vitro employing the phenomenon of Leukocyte Migration Inhibition (LMI). The present invention differs from the previously described LMI technique in that antigens are individually incorporated into the agarose of assay plates, requiring no preincubation of antigens with patient blood cell (leukocyte) suspensions. The LMI assay method described herein is a practical alternative to delayed hypersensitivity skin testing to identify cellular immune deficiency and avoids the risk and inconvenience of the skin test procedure. The method also allows in vitro diagnosis of Tuberculosis and monitoring of tumor therapy.

Abstract: A particle washing system and method of use is described wherein in a preferred embodiment the fluid containing the desired particles is placed within an inner tube having near the bottom thereof an orifice with a diameter at least equal to that of the diameter of the particles, and wherein the inner tube is positioned within an outer tube having a fluid with a density at least equal to that of the solution containing the particles to be separated but less than that of the particles. The application of centrifugal force to the particles directed toward the bottom of the outer tube causes the particles to move through the orifice and through the outer solution contained within the outer tube so that the particles are collected from the inner solution, washed by the outer solution, and subsequently sedimented at the bottom of the outer tube.

Abstract: A particle washing system and method of use is described wherein in a preferred embodiment the fluid containing the desired particles is placed within an inner tube having near the bottom thereof an orifice with a diameter at least equal to that of the diameter of the particles, an air vent and, wherein the inner tube is positioned within an outer tube having a fluid with a density at least equal to that of the solution containing the particles to be separated within the inner tube but less than that of the particles. The application of centrifugal force to the particles directed toward the bottom of the outer tube causes the particles to move through orifice and through the outer solution contained within the outer tube so that the particles are collected from the inner solution, washed by the outer solution, and subsequently sedimented at the bottom of the outer tube.

Abstract: An immunological substance detecting reagent is provided which, in the preferred embodiment, employs an immunological homolog specific for the immunological substance to be detected coupled to a water-soluble polymer having a net charge not greater than zero. The water-soluble polymer further has associated a plurality of marker substances such as fluorophore molecules thereby providing a reagent of increased sensitivity for the detection of an antigen-antibody immunological reaction.

Abstract: Methods for producing from human serum, human gamma globulin essentially free of HB.sub.s Ag and products resulting therefrom. Specifically provided are ion exchange resin/buffer systems capable of effectively removing HB.sub.s Ag thought to be closely correlated with viral hepatitis type B infectivity. Additional steps can include ultrafiltration to increase reduction of any virus not removed in the column passage as well as the addition of anti-HB.sub.g to substantially eliminate all infectivity.

Abstract: Reagents and methods are described for an immunoassay test of increased sensitivity and decreased complexity employing an immunoglobulin specific for an antigen naturally or artificially placed upon the surface of an indicator particle coupled through the use of a hetero-bifunctional coupling reagent to a second antibody of differing specificity and specific for the antigen to be detected. In a preferred embodiment, a hetero-bifunctional coupling agent couples via a sulfhydryl group, a univalent immunoglobulin specific for the surface antigens on erythrocytes to a second multivalent immunoglobulin through an amide linkage with the latter immunoglobulin wherein said second immunoglobulin is specific for hepatitis-B surface antigen.

Abstract: Method for detecting circulating immune complexes containing endogenously bound Clq. Capillary tubes are filled with a mixture of Clq coated GPO reagent cells, rabbit anti-Clq antibodies, and precipitate from the biological fluid sample containing immune complexes. The mixture is allowed to react and the tubes read for the presence or absence of agglutination indicative of the absence or presence of said immune complexes respectively.

Abstract: A reagent kit for eluting antibodies present on the surface of red blood cells comprises sorbitan trioleate or other variants within the sorbitan family and a red blood cell diluent as well as methods for use.

Abstract: Kit for detecting circulating immune complexes containing endogenously bound Clq. Capillary tubes are filled with a mixture of Clq coated GPO reagent cells, rabbit anti-Clq antibodies, and precipitate from the biological fluid sample containing immune complexes. The mixture is allowed to react and the tubes read for the presence or absence of agglutination indicative of the absence or presence of said immune complexes respectively.

Abstract: Methods and apparatus wherein a very small number of sorted cells are attached to specified locations on a microscope slide circumscribed by well areas of a retainer slip. The cells are deposited in the wells and during centrifugation of the slide-retainer sandwich, are contacted with and attached to the serum albumin present in the well and coated on the slide. Removal of excess fluids, optional clamping means and the retainer slip followed by air drying provides for permanent attachment of rare, sorted cells in a localized, known area for subsequent staining, examination and analysis.

Abstract: Methods and compositions for quantitating reticulocytes and platelets by fluorescence in a flow cytometer. The composition comprises an aqueous solution of the dye acridine orange, citrate ion, and para-formaldehyde at a pH of about 7.4 and an isotonic osmolality. The concentrations of the various ingredients are selected to maximized dye uptake by the reticulocytes and platelets to allow for the first time the fluorescent quantitation of these cells in whole blood using a flow cytometer.

Abstract: A sample of whole blood is stained with an acridine orange reagent, and is analyzed rapidly, a cell at a time, in a flow cytometry system having a sample stream dimension in the range of expected red cell dimensions. Red florescence and forward scatter data is utilized first to discriminate a cell from noise, and then to distinguish platelets from reticulocytes and red cells. The red cell and reticulocyte data is subjected to a correction such as rotational coordinate shift, and the shifted data are, by means of statistical procedures, utilized to determine threshold criteria separating red cells from reticulocytes, and to enumerate the cells on that basis.