Chemistry: molecular biology and microbiology – Measuring or testing process involving enzymes or... – Involving antigen-antibody binding – specific binding protein...
Reexamination Certificate
1994-09-09
2003-06-17
Nguyen, Bao-Thuy L. (Department: 1641)
Chemistry: molecular biology and microbiology
Measuring or testing process involving enzymes or...
Involving antigen-antibody binding, specific binding protein...
C422S073000, C422S082080, C436S172000, C436S805000, C436S824000, C436S825000, C435S808000, C435S962000
Reexamination Certificate
active
06579685
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates generally to a method and apparatus for screening microscopic cells which express selected characteristics utilizing light scatter or light scatter and electronic sensing techniques. More particularly, the invention is directed to an analysis of one or more cell groups of interest obscured in a cell population by utilizing microspheres having monoclonal antibodies bound thereto to change the sensed characteristics of each specified cell to differentiate the cells of the cell group of interest from the cell population.
This invention relates generally to an automated analyzer and methods of using same for screening biological cells or formed bodies for the enumeration of populations which express selected characteristics for research, diagnostic, medical or industrial purposes. More particularly, the automated analyzers and methods embodying the invention enable multiple part classifications of cells and formed bodies, functional phenotyping of cells and formed bodies, typing of leukemic, lymphoma and solid tumor cells, among others, using a unique combination of optical or optical and electronic technology and the specificity of selective biological molecules, such as antibodies, for such screening and selective enumeration of the cells and formed bodies.
Automation of routine complete blood cell (CBC) analysis of human peripheral blood by an automated blood cell counter was successfully achieved by the COULTER COUNTER (registered trademark) Model A of Coulter Electronics, Inc. of Hialeah, Fla. The electronic particle sensing system principle of that instrument is disclosed in U.S. Pat. No. 2,656,508 issued Oct. 20, 1953 to Wallace H. Coulter. This Coulter sensing principle was developed and expanded into more sophisticated instrumentation such as the COULTER COUNTER (registered trademark) Model S types of instruments which enabled CBC parameters, absolute cell counts, platelet count and morphology, red blood cell (RBC) morphology, interpretation of normal and abnormal blood specimens by specific computer programs.
The Coulter electronic particle sensing principle employs an aperture sensing circuit using a direct current (DC) aperture supply. Such particle sensors are simple in structure, extremely rugged and reliable as attested to by the substantially universal acceptance of the COULTER COUNTER (registered trademark) automated analyzer in clinical laboratories in the United States and throughout the rest of the World. An improvement in this basic aperture sensing circuit was disclosed in U.S. Pat. No. 3,502,974 issued in 1970 to Wallace Coulter and Walter Hogg. In addition to the standard direct current aperture supply, a high frequency aperture current was applied which enabled the sensing of an additional parameter for classification purposes. The high frequency aperture current produced a signal which is the function of the blood cell's internal conductivity as well as its volume. The signal produced simultaneously by the direct current aperture circuit is a conventional DC amplitude signal which provides an indication primarily of cell volume. The radio frequency amplitude is divided by the direct current pulse amplitude employing a high speed divider circuit to obtain a quotient which is a function of cell volume and internal resistance, conveniently referred to as “opacity”. This principle is further described in U.S. Pat. No. 3,502,973 also issued to Wallace Coulter and Walter Hogg, in 1970. The opacity parameter has applicability in cell classification systems. Either a single or a pair of separate apertures could be utilized for this purpose.
Classification of different populations is accomplished by collating the data of the signal pairs as they are produced; one, a measure of particle volume and the other a measure of cell internal resistivity or opacity. A convenient form of presenting this data is by two-dimensional plots referred to as scatterplots or scattergrams. Such plots are well described in
Flow Cytometry and Sorting,
page 371; edited by Melamed Melaney, and Medelsohn, 1979, John Wiley & Sons, NY, N.Y.
Initial applications of the Coulter electronic particle sensing principle was to perform red blood cell counts and then, more sophisticated determinations of other red blood cell parameters. By removing red blood cells from whole peripheral blood, analysis of the white blood cell (WBC) populations could be undertaken so long as the red blood cell removal did not significantly impair properties of the remaining white blood cell populations sought to be measured. Red blood cell lysing reagents were developed for this purpose which, though useful and widely applied, were not entirely satisfactory in all respects for subsequent white blood cell determinations.
Previous methods of flow analysis of leukocytes using DC volume alone or light scatter at various angles have shown three clusters of leukocytes corresponding to lymphocytes, monocytes and granulocytes which included the neutrophil, basophil and eosinophil populations. A rough but useful estimation of eosinophil concentration can be made on some samples. The fifth major population, basophils, is relatively too small for this approach.
Immunologic studies also are important when anomalies are found on a peripheral blood smear. It is necessary to determine the specific subtype of the leukemia in order to better select a treatment method for the disease and to provide the patient with as specific a prognosis as possible. For example, in forms of acute leukemia, there is a predominance of blasts in the peripheral blood. These immature cells can be difficult to classify as either lymphocytic or granulocytic because of the lack of differentiation. If the blast subpopulation that is rapidly proliferating is found to be T
11
receptor bearing, the leukemia can be classified as an acute lymphoblastic leukemia, T-cell type. In general, T lineage ALL has a poorer prognosis than B lineage ALL. Further subgrouping these leukemias according to their level of differentiation is also customary. Groups I and II exhibit antigens that are seen on early thymic precursor cells; while those expressed in Group III are similar to the surface antigens found on mature T cells. Information such as this regarding the surface antigens expressed on leukemic cells is useful for patient prognosis and treatment.
Immunology experiments were first developed utilizing a light microscope for determination of lymphocyte subsets. Rosette formation between human lymphocytes and sheep red blood cells was observed by Coombs and others in 1970. Later studies found that all or at least a major portion of thymus-derived lymphocytes (T-cells) under the proper conditions displayed the rosette formation phenomenon. These studies utilized Ficoll isolated lymphocytes and were for a period of time routinely employed for subset classification of isolated lymphocytes utilizing a light microscope.
Lymphocyte subsets now conventionally are determined by fluorescent labeling of the cells, in a sample with a fluorescent-tagged monoclonal antibody. The fluorescent-tagged monoclonal antibody binds to the antigen of interest on the surface of the cells expressing the antigen. The cell sample then is analyzed by utilizing a fluorescent microscope or by utilizing a highly sophisticated flow cytometry instrument. When utilizing a flow cytometry instrument, the cell sample preparation, data collection and data analysis must be performed by a specially trained technician. The flow cytometry instrument includes a laser and complex optical system, a high-power computer and electrical and fluidic systems. The component systems of the flow cytometry instrument must be properly maintained and calibrated on a regular and frequent basis. Although the flow cytometry instrument currently is the reference lymphocyte subset determination method, the method has several drawbacks including the high cost of the instrument and the expertise required to correctly operate such instrument.
Lymphocyte subsets also can be determ
Coulter Wallace H.
Hajek Constance Mary
Hudson James Carey
Rodriguez Carlos M.
Russell Thomas
Alter Mitchell E.
Coulter International Corp.
Kurz Warren W.
Nguyen Bao-Thuy L.
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