Abstract: A method of lyophilizing mammalian cells to produce preserved human cells, hybridoma cell lines, tissue cells, and control cells for immunoassays and other hematological measurements. Prior to freezing and lyophilizing, the prepared mammalian cell pellet is suspended in a solution of trehalose in an isotonic fluid prepared at a specified optimal concentration and incubated at room temperature for a designated time period. The lyophilized cells when rehydrated, retain their optimal physiological characteristics suitable for use as an analytical control and retain said characteristics after storage at 2.degree.-8.degree. C. for a period in excess of five (5) months.

Abstract: The method of this invention is directed to the rapid preparation of a whole blood sample for photooptical analysis. In the preferred embodiments of this method, a whole blood sample, lytic reagent system and immunological stain (optional) are contacted with the sample in a common reaction vessel (i.e. cuvette or test tube), with gentle asymmetric vortex mixing, so as to maintain the particulate matter of the sample at an essentially homogeneous concentration throughout the sample. An aliquot of the contents of the reaction vessel can, thereafter, be analyzed for identification and/or quantification of the analyte of interest.

Abstract: A coincidence arbitration system for a sorting cytomteter which detects and sorts particles using a flow chamber and a stream of droplets. Those droplets containing selected particles are sorted by selectively applying a charge thereto and passing the droplets through deflection plates. After detection, the particle data is delayed and analyzed to make sort decisions. The delay is for a period of one and one fourth droplet time periods less than the time the particle is formed into a droplet. At the time the command is issued creating the charge on the droplet to be formed, the coincidence arbitration circuit looks four quarter droplet times ahead and behind of the event to determine whether a coincidence is occurring, and if so, whether the coincidence is with a similar type of particle or a different type of particle. Based on this information, appropriated sort or no-sort commands are issued.

Abstract: A hybrid cell line is provided which is capable of producing monoclonal antibodies which bind to HIV core antigen P55, the precursor protein coded for the gag gene, the core protein P24 and partial breakdown products P39 and P33. The monoclonal antibody embodying the invention does not bind the P18 core protein or any HIV envelope antigens. The cell line of the invention was developed by a unique immunization protocol in which BALB/c mice were immunized over a series of multiple infusions using a select group of immunogens and a conventional myeloma cell line for fusion with the murine splenocytes harvested.The monoclonal antibody is identified as the KC-57 antibody. This monoclonal antibody is especially useful for a solid phase immunoassay in which the monoclonal antibody is detected in its binding to HIV antigens found in a serum or plasma sample from a human patient. The cell line which produces the KC-57 monoclonal antibody has been deposited in the American Type Culture Collection, Rockville, Md.

Abstract: A solid-phase immunoassay is provided for determination of HIV antigens in human physiological fluid. The immunoassay is characterized by the coating of a solid substrate with a unique monoclonal antibody which recognizes a common antigenic determinant of a group of HIV core antigens and no HIV envelope antigens of HIV. The test sample preferably also is subjected to a lysing reagent prior to the incubation for uniformly dispersing antigens which may be present in the test sample.

Abstract: A solid-phase immunoassay is provided for determination of members of an immunological pair such as antigen and/or antibody of a single binding pair in human physiological fluid, wherein a single immunoassay enables simultaneous detection of antigen and/or antibody of a single binding pair in a test sample which may have circulating antigen and/or antibody. The immunoassay is characterized by the addition of an amount of antigen or "spike" of the binding pair to the test sample prior to incubation of the test sample in the presence of a solid-phase absorbed antibody of the binding pair. The test sample preferably also is subjected to a lysing reagent prior to the incubation for uniformly dispensing antigens which may be present in the test sample.

Abstract: A hybrid cell line capable of producing monoclonal antibodies uniquely specific to human neutrophils and eosinophils and exhibiting no specificity for lymphocytes, basophils and monocytes. Further there is noreactivity with acute leukemia cells. One of the partners in the hybridoma fusion of a mouse spleen cell developed from using human granulocytes as the immunization agent. The monoclonal antibody further is capable of being used to enumerate and isolate neutrophils in normal peripheral blood and possibly in blood of patients with acute leukemia.

Abstract: Automatic biological sample mixing apparatus for use in flow cytometry, wherein a sample container is secured loosely at its top by means of a multi-reagent dispensing head; and the container is mounted at its bottom on a resilient support disposed on an elliptically rotated member, to cause reagents introduced into the container to be thoroughly mixed with a sample in the container in a fast, efficient, gentle, and accurately repeatable manner.

Abstract: A chemical agent is provided for significantly preventing or blocking non-specific staining or binding of an antibody specific for Terminal deoxynucleotidyl Transferase (TdT) during immunofluorescent or immunoperoxidase assay procedures. These procedures include both immunofluorescent and immunohistochemical staining of samples followed by flow cytometric and/or microscopic analysis, respectively. The invention is practiced by selective use of casein introduced into the assay procedures at an appropriate interval prior to analysis using a labelled or tagged monoclonal antibody specific to a TdT epitope. The casein utilized successfully was obtained from a large variety of sources and includes the use of a non-fat milk product.

Abstract: A control slide for use in an immunoassay having a section of a cell pellet retained on the slide in a stable and substantially permanent formation which can be stored at room temperature. Further, the invention includes the method of making the control slide.

Abstract: A murine monoclonal antibody which selectively binds to the determinant site or specific epitope of glycophorin A exposed on the membrane of the erythrocyte and does not bind to other glycophorins. The monoclonal antibody is coated on a microsphere or substrate of a suitable monodispersed variety and utilized in a separation procedure for recovery of white blood cell subsets without lysing of erythrocytes. The bound microspheres are recovered without adverse depletion of the white blood cell population of the sample. The microsphere or bead-to-cell ratio employed is most acceptable for commercial applications of the invention. The invention thus enables accurate assaying of white blood cell subsets in circulating peripheral blood without resorting to lysing of erythrocytes.

Abstract: Detection of an identified human carcinoma tumor antigen in a pathological sample by means of a labelled monoclonal antibody specific to the determinant site on the antigen is enhanced and/or accelerated at an earlier development stage than heretofore achieved by removing a carbohydrate steric hindrance for monoclonal antibody availability to bind the antigen of the tumor for which it is specific. The carbohydrate steric hindrance for monoclonal binding to the antigen is identified as sialic acid. The method of the invention involves selective removal of sialic acid from the antigen's determinant site by enzymatic digestion using neuraminidase.

Abstract: A murine monoclonal antibody specific for an antigenic determinant on the surface or in the cytoplasm of human carcinoma cells and tissue. A cell line is provided for producing such specific monoclonal antibodies for the detection, diagnosis, and therapeutic treatment of a plurality of human carcinomas by means of selective labelling of said monoclonal antibodies.

Abstract: A particle separator for sorting particles suspended in a liquid according to certain characteristics, including a method of and apparatus for detecting a change in the droplet breakoff point of a liquid jet stream which is subjected to vibrations. The vibrations produce amplitude undulations on the surface of the jet stream. The amplitude of the undulations is monitored or interrogated at a fixed point on the jet stream prior to the breakoff point. A change in amplitude of the undulations at that fixed point produces a signal voltage at a masked sense diode the value of which is proportional to the amplitude change. This signal voltage may be used (1) to alert the operator that a change has occurred in the point at which the jet stream is breaking up into droplets, (2) to automatically control the intensity of the vibrations for restoring the amplitude of undulation at that fixed point to its original state, or (3) to automatically disable the sorting portion of the apparatus.

Abstract: A method and apparatus for removing foreign matter, including debris and deposits and air bubbles from a flow cell of a particle study device. The apparatus includes a chamber with an aperture containing unit at one end and sample and sheath introduction mechanisms at the other end to supply respectively, a sample suspension of particles and a particle free liquid. The chamber has a waste orifice positionally disposed to provide a turbulent flow of particle free liquid within the chamber upon simultaneous injection and exhaustion of the particle free liquid into and out of, respectively, the sheath introduction mechanism and the waste orifice, to remove any air bubbles in the chamber and its adjacent aperture area.

Abstract: Method of and apparatus for handling a microsample comprising a probe for aspirating a sample and a cleaning mechanism having a passageway within which the probe is movable. The passageway has a cleaning chamber having opposite ends, one end being open to the atmosphere and proximate the sample. The cleaning mechanism further includes a fluid directing means and two vacuum applying means, the vacuum applying means being disposed at opposite ends of the chamber and the fluid directing means being disposed between them. During a cleaning mode the fluid directing means directs a wash fluid against the probe and the vacuum applying means removes the wash fluid, prevents exiting of the wash fluid and drys the probe, the later two by permitting gas from the atmosphere to flow into the cleaning chamber.

Abstract: Disclosed is a flow-through, particle analyzer and sorter apparatus for simultaneous optical and electrical impedance measurements on a stream of particles, comprising a flow cell having a pair of channels fluidly connected by a particle sensing aperture, through which the particles pass and are analyzed; a nozzle mounted at the end of the downstream channel so as to define a flow chamber; a sheath liquid which is introduced at the bottom of the flow chamber to hydrodynamically focus the particle stream and to jet the same in a liquid jet from the nozzle; and a system for creating droplets from the liquid jet and for thereafter sorting the droplets.

Abstract: A particle separator for sorting particles suspended in a liquid according to certain characteristics, including a method of and apparatus for detecting a change in the droplet breakoff point of a liquid jet stream which is subjected to vibrations. The vibrations produce amplitude undulations on the surface of the jet stream. The amplitude of the undulations is monitored or interrogated at a fixed point on the jet stream prior to the breakoff point. A change in amplitude of the undulations at that fixed point produces a signal voltage the value of which is proportional to the amplitude change. This signal voltage may be used (1) to alert the operator that a change has occurred in the point at which the jet stream is breaking up into droplets, (2) to automatically control the intensity of the vibrations for restoring the amplitude of undulation at that fixed point to its original state, or (3) to automatically disable the sorting portion of the apparatus.

Abstract: Disclosed is an improved centrifuge apparatus for separating substances of varying density and a method of controlling the speed of a rotor of the centrifuge apparatus. A vent-view port is mounted for in-out adjustment within an access aperture formed in a lid of the centrifuge apparatus so as to provide for selective opening of vent holes formed in the vent-view port. In addition to venting, the vent-view port has a sensor mount with a transparent window for receiving a tachometer probe for rotor speed monitoring. Additionally, a desired centrifugal force and a desired accumulative centrifugal force can be entered by a human operator. A control unit adjusts the rotor speed and operational cycle time to meet the inputted desired force values while displaying the actual accumulative centrifugal force at the end of the operation cycle.