Abstract: The present invention provides a low cost imaged-based system for detecting, measuring and/or counting labeled features of biological samples, particularly blood specimens. In one aspect, the invention includes a system for imaging multiple features of a specimen that includes one or more light sources capable of successively generating illumination beams each having a distinct wavelength band and a plurality of differentially excitable labels capable of labeling a specimen comprising multiple features, such that each different feature is labeled with a different differentially excitable label.

Abstract: The present invention provides an optical cuvette for use in a flow-type particle analyzer, wherein the cuvette includes a removable flow tube containing a flow channel oriented coaxially.

Abstract: The present invention provides an optical analyzer having illumination optics that include a light source, such as a laser or other source, adapted to emit a collimated, or approximately collimated, light beam, and a focusing lens that focuses the beam onto a focus spot within a detection region, wherein the focusing lens is mounted in a lens positioning apparatus that allows for precise positioning of the focus spot within the detection region. The lens positioning apparatus comprises a lens holder adapted to rotate through a small angle around a pivot axis parallel to the optical path, such that the lens holder rotates in a plane perpendicular to the optical path, and an actuator adapted to provide an angular displacement of the lens holder around the pivot axis. The lens holder holds the focusing lens at a first distance from the pivot axis, and is coupled to the actuator at a second distance from the pivot axis, wherein the second distance is larger than the first distance.

Abstract: The present invention provides multicolor reagent formulations containing in a single container both fluorescently labeled detection reagents and single-color compensation control reagents, wherein the compensation control reagents consist of reagent-capture particles bound to a fluorescently labeled detection reagent included in the multicolor reagent formulation. The multicolor reagent formulations of the present invention simplify manufacture and commercial distribution of multicolor reagent kits.

Abstract: The invention provides a flow system and method for reliable multiparameter data acquisition and particle sorting. In accordance with the invention, a flow system assesses changes in the pattern of data collected in successive time intervals and actuates one or more corrective actions whenever the changes exceed predetermined limits. The present invention overcomes problems associated with collecting data and sorting and enumerating particles in flow cytometry systems that operate for prolonged periods or that must accommodate samples that vary widely in quality.

Abstract: The present invention proves instruments and methods for detecting and/or quantitating an analyte in a fluid sample. The fluid sample is placed in a sample chamber having a small, shallow detection region. The analyte is magnetically labeled using magnetic particles coated with a binding reagent, and is detectably labeled using a fluorescent dye or other detection reagent. The magnetically labeled analyte is concentrated into the detection region using a focusing magnet positioned underneath the sample chamber detection region. Concentrated analyte is measured using excitation optics positioned on top of the sample chamber detection region, adapted to illuminate only the detection region, and detection optics positioned on top of the detection region, adapted to detect only light emitted from the detection region. In a preferred embodiment, the invention provides a simple, rapid assay for measuring the concentration of CD4+T cells in a whole blood sample.

Abstract: The present invention provides deflection plates for use in a flow-type particle sorter that are resistant to wetting. The deflection plates include a gas-porous, conductive plate. A gas, such as air, is passed through the plate from the outer face (away from the particle flow) towards the inner face (towards the particle flow). The flow of gas prevents condensation on the inner face of the defection plate.

Abstract: The invention provides methods and compositions for identifying and counting lymphocytes in a biological sample, such as whole blood, by means of a probe comprising at least one binding compound specific for a T lymphocyte-specific marker, e.g. a CD2 or CD3, and at least one binding compound specific for CD45RA. Lymphocytes within the sample combine with such a probe to form a distinguishable subpopulation based on the amount of probe that specifically binds to their surfaces, thereby permitting such lymphocytes to be detected and enumerated on the basis of the intensity of the signal generated by the probe, and without the need of a separate physical measurement, such as light scatter. With additional probes specific for additional blood cell markers, percentages of lymphocytes, monocytes and granulocytes in a sample may be determined.

Abstract: The present invention provides an optical analyzer having illumination optics that include a light source, such as a laser or other source, adapted to emit a collimated, or approximately collimated, light beam, a focusing lens that focuses the beam onto a focus spot within a detection region, and beam-adjusting optics positioned in the light path between the light beam source and the focusing lens, which allow for precise positioning of the focus spot within the detection region. The beam-adjusting optics of the present invention comprise at least one movable focusing lens, mounted in a positioning device that allows repositioning of the lens in a plane perpendicular to the light path.

Abstract: Arrays of microparticle populations, each population labeled with a single fluorescent dye, are provided for use in multiplex assays. The populations form a virtual multidimensional array wherein each microparticle is identified by fluorescence intensity in two different fluorescence detection channels. The arrays are useful in a variety of assays, including multiplex, multi-analyte assays for the simultaneous detection of two or more analytes by, for example, flow cytometry, and a labeling reagents in, for example, microscopy. The use of singly-dyed microparticles to form multidimensional arrays greatly simplifies the creation of multiplex assays.

Abstract: An enhanced detection system can eliminate use of a sheath fluid by selecting which particles that pass through an sensing region to detect parametric characteristics thereof based upon position of each particle while it is in a sensing region relative to one or more predetermined positions, such as an in-focus position relative to one or more light beams directed into the sensing region, to enhance accuracy and robustness of particle parametric characteristics detection.

Abstract: The invention provides an apparatus including (a) a frame having a boundary plane; (b) a flow chamber supported by the frame, the flow chamber placed a distance from the boundary plane; (c) a radiation source, the radiation source directed away from the flow chamber and away from the exterior side of the boundary plane, and (d) a first reflective surface placed to direct a radiation beam in a path crossing the boundary plane to the flow chamber; (e) one or more reflective surfaces placed to direct a radiation beam from the radiation source to the first reflective surface, the path from the radiation source to the flow chamber being at least 1.5 times the distance from the flow chamber to the boundary plane.

Abstract: A flow cell and flow cytometer in which a nozzle at the end of a flow channel is disposed on a removable substrate held at a registered location on a flow cell. Other elements including illumination optics, light collection optics, and the flow cell may then be positioned at fixed locations and would not require subsequent periodic adjustment. The registered location for positioning the nozzle allows removal and replacement of the nozzle key with the nozzle subsequently positioned in the identical location.

Abstract: This invention comprises a novel approach to the assessment of antigen-specific T cells that quantitates and characterizes these cells with unprecedented clarity, and importantly, because it is performed in whole blood, is amenable to routine use in the clinical immunology laboratory. The methodology offers an improved flow cytometric intracellular cytokine assay in whole blood that can simultaneously measure multiple T cell subsets expressing multiple cytokines from a single whole blood culture. Evaluation of whole blood antigen specific cytokine responses has the important advantage of assessing T cell activation in the presence of ALL types of MHC autologous antigen presenting cells present in the native sample. It also has the advantage of enabling a culture system (whole blood) which can reflect effects of systemic environments (i.e.

Abstract: Arrays of microparticle populations, each population labeled with a single fluorescent dye, are provided for use in multiplex assays. The populations form a virtual multidimensional array wherein each microparticle is identified by fluorescence intensity in two different fluorescence detection channels. The arrays are useful in a variety of assays, including multiplex, multi-analyte assays for the simultaneous detection of two or more analytes by, for example, flow cytometry, and a labeling reagents in, for example, microscopy. The use of singly-dyed microparticles to form multidimensional arrays greatly simplifies the creation of multiplex assays.

Abstract: Diagnostic methods, systems, and kits for identifying patients with systemic inflammatory response syndrome who are likely to progress to sepsis.

Abstract: The invention provides a flow cytometric method for measuring dendritic cell function in whole blood, comprising: (a) contacting a whole blood sample with a dendritic cell activator; (b) adding to the sample a plurality of dendritic cell-distinguishing antibodies and at least one cytokine-specific antibody; and then (c) flow cytometrically assaying the sample for the binding of the cytokine-specific antibody by at least one distinguishable DC subset. Other assays are presented in which DC activation markers are assessed.

Abstract: Presented are intrinsically fluorescent, self-multimerizing MHC fusion proteins, and complexes assembled therefrom that are capable of detectably labeling antigen-specific T lymphocytes. Also presented are methods for labeling antigen-specific T lymphocytes with the intrinsically fluorescent complexes of the present invention, and methods, particularly flow cytometric methods, for detecting, enumerating, enriching, and depleting antigen specific T lymphocytes so labeled.

Abstract: A flow cell and flow cytometer in which a nozzle at the end of a flow channel is disposed on a removable substrate held at a registered location on a flow cell. Other elements including illumination optics, light collection optics, and the flow cell may then be positioned at fixed locations and would not require subsequent periodic adjustment. The registered location for positioning the nozzle allows removal and replacement of the nozzle key with the nozzle subsequently positioned in the identical location.

Abstract: An optical instrument using a plurality of lasers of different colors with parallel, closely spaced beams to stimulate scattering and fluorescence from fluorescent biological particulate matter, including cells and large molecules. A large numerical aperture objective lens collects fluorescent light while maintaining spatial separation of light stimulated by the different sources. The collected light is imaged into a plurality of fibers, one fiber associated with each optical source, which conducts light to a plurality of arrays of detectors, with each array associated with light from one of the fibers and one of the lasers. A detector array has up to ten detectors arranged to separate and measure colors within relatively narrow bands by decimation of light arriving in a fiber.