Title of Invention

PRODUCTS AND METHODS FOR SINGLE PARAMETER AND MULTIPARAMETER PHENOTYPING OF CELLS

Abstract A method of characterizing cells comprising the steps of: providing a suspension of cells in a liquid medium, said cells including first cells, contacting a group of first beads with said suspension, each of said first beads being coated with a binding substance or being magnetic such that each first bead is adapted to bind to at least one of said first cells, incubating said first bead with said suspension for a period of time effective to permit said first cells to bind to said first beads to form first bead-first cell complexes, each first bead-first cell complex comprising a first bead and a first cell, separating said first bead-first cell complexes from said suspension by filtration through a filter, and examining said separated first bead-first cell complexes and characterizing said first cells.
Full Text This application claims the benefit of U.S. Provisional Application Serial No. 60/132,395
filed May 4, 1999. The contents of said Provisional Application Serial No. 60/132,395 are
incorporated herein by reference in their entirety.
FIELD OF THE INVENTION
The present invention relates generally to phenotyping and immunophenotyping of cells
and more particularly to single parameter and multiparameter phenotyping and immunophenotyping
of cells.
BACKGROUND OF THE INVENTION
Immunophenotyping of cells and tumors, particularly hematopoietic tumors, is often of
critical importance for clinical evaluation of cancer patients. However, currently available
'methodologies, particularly flow cytometry, are expensive and require a high degree of suspicion at
the time of biopsy. All too often, even before the diagnosis of cancer is made, precious tissue
must be set aside for possible immunophenotyping. If tissue is not set aside and there is cancer
present, the correct subtyping of the tumor (and proper assignment to treatment protocols) cannot
be done after the fact. Methods that do not require forethought, such as inununostaining of
paraffin blocks, are far less sensitive and do not work well in laboratories that do not perform these
stains frequently. Flow cytometry is the currently accepted "gold standard" for
immunophenotyping of hematopoietic cell types.. However, there are several problems with the
method. The expense of establishing and maintaining these laboratories is perhaps the most severe
problem. Generally large hospitals, academic centers, or commercial reference laboratories are the
only institutions capable of establishing cytometry laboratories. These laboratories often
charge a premium for their services, and transportation of specimens to laboratories is not a trivial
problem. Since flow cytometry requires live cells, specimens must be handled under sterile
conditions. In laboratories where the technology is unavailable, a fresh specimen has to be
prepared and shipped to a flow cytometry laboratory under sterile conditions for evaluation.
Uncontrollable factors such as temperature variations, rough handling, bacterial contamination, or
shipping delays may render samples unsuitable for analysis. In addition, flow cytometry requires
technologists who have specialized training and their time must often be dedicated solely to the
technology itself, further increasing the expense of the procedure. Relatively large volumes of cells
must be analyzed in order to obtain statistically meaningful results during analysis. In addition, red
cells must be removed from the sample prior to analysis. This is because the number of red cells
in blood and bone marrow samples is far greater than other cells types, and shear numbers alone
would overwhelm the sensitive detectors of the machines. The sample preparation method
therefore requires Ficoll-Hypaque separation, followed by multiple washes, followed by a lysis step
to lyse remaining red cells. This method virtually eliminates megakaryocytes from most analysis
and frequently destroys delicate malignant cells (particularly from the relatively common tumors
such as large cell lymphoma and Hodgkin's disease). It is in these situations that the great
sensitivity and complexity of flow cytometry may work to its disadvantage.
Despite the problems described above, however, flow cytometry can very accurately and
with great sensitivity identify the presence of malignant cells and characterize the kino or malignant
cells. Without the information that flow cytometry provides, cases can be frequently incorrectly
diagnosed with catastrophic consequences for the patient. This is particularly true in the setting of
a type of biopsy called fine needle aspiration where examination of a slide alone by light
microscopy may be quite difficult.
What would be very useful to the average hospital pathologist or to any physician in an
outpatient or remote setting is a device or kit that would allow the same kind of single parameter or
multiparameter analysis of samples using cheaper, more readily available materials. This would
eliminate the need for specialized laboratories and technologists dedicated solely to the flow
cytometry technology itself and would allow any well trained clinical laboratorian ready access to
the same kind of analysis. Furthermore, if the need for live cells could be eliminated, cells could
be preserved by appropriate fixatives which would broaden the availability of immunophenotyping
data.
Over the last 20 years there has been a tremendous growth in the identification and
characterization of molecules expressed by blood cells on their cell membranes (called cell surface
antigens). This growth in understanding has been accompanied by the refinement of technologies
that allow the rapid and sensitive identification of these molecules on the surfaces of live cells.
However, the overwhelming majority of these cell surface antigens are not unique to one type of
cell. There is only rarely a single diagnostic marker to identify a cell type. Instead, most cell
populations must be characterizing by analyzing multiple parameters at the same time.
Antibodies are proteins produced by the body's immune system that have the property that
they bind to a singe specific molecule (referred to as an antigen). Antigen-antibody complexes are
formed when an antibody binds its respective antigen. Normally, these complexes are then cleared
by the immune system to rid the body of an infection. However, the immune system has a
virtually limitless capacity to produce unique antibodies, which can be tailored to identify particular
substances, even when present in very small quantities. Antibodies are now commercially
produced to literally hundreds of different antigens. Furthermore, antibodies can be easily tagged
with marker molecules, such as fluorescent molecules, dyes, or other substances that make
identifying the presence of an antigen-antibody complex a relatively simple matter. This well-
known biochemical reaction has been used to develop a methodology called flow cylometry. In
flow cytometry. intact cells are treated with antibodies that bind specific markers on the cell
surface. The antibodies are, in turn, labeled with a fluorescent molecule and the cell suspension
then flows past a light beam with a light detector which counts the number of fluorescent cells
versus the other cells present. This technology has proved tremendously useful in identifying
malignant cell populations in blood and tissue samples from patients.
In flow cytometry, a cell suspension is treated with antibodies labeled with fluorescent
molecules (fluorochromes), washed, and placed in the machine. The cell suspension is "focused"
using buffer solutions so that the cells pass through the flow detector in a single file. When each
cell passes through the flow detector, a beam of laser light is passed through the cell. Some of the
light passes through the cell (called forward light scatter) and some is refracted at an angle (called
side scatter). Forward scatter increases with a celt's size and side scatter increases with a cell's
internal complexity (mostly granules within the cytoplasm). Thus using just these two
measurements, individual cell types can be roughly categorized. However, there are also light
detectors, which, by using appropriate color filters, can specifically detect the fluorescence given
off by the antibodies that are attached to the cell surface. Since current state of the art machines
have up to four different color detectors (referred to as four-color flow cytometry), up to four
different antibodies can be added to the same tube. Samples from individual patients are usually
divided into multiple tubes, each of which contains multiple antibodies. Data analysis is therefore
quite complex, and requires computers that are capable of simultaneously displaying multiple plots
from each tube. This is referred to as multinarameter analysis. This simultaneous analysis of
multiple parameters is necessary to first electronically isolate and then characterize ceil populations.
Therefore, even though modern flow cytometers analyze up to 6 simultaneous parameters (forward
scatter, side scatter, and four antibodies) 3 of the parameters must be used for electronic isolation
of cell types (forward scatter, side scatter, and CD4S staining intensity). Broad categories of cells
present in hematologic samples are known in the art and include myeloid cells, monocytes,
lymphocytes, megakaryocytes, and red cells. In other words, these 3 parameters must he used to
roughly mimic what the human eye does so effortlessly: identify or characterize broad categories of
cells. Indeed, laboratories commonly hire technicians with 2 years of training (only part of which
is in the area of hematology) who can, with a very reasonable degree of accuracy and precision,
identify or characterize different cell types present in blood samples. With some additional
training, they can also correctly enumerate cell types within bone marrow aspirate samples. Thus
if the human eye were also equipped with the means to also identify cell surface antigens, there
would be no need for flow cytometry for this purpose. Furthermore, of the remaining 3
parameters available for analysis on the flow cytometry, only 2 can be displayed in any one plot
although new software exists that can display 3 dimensional plots. While 3 dimensional plots add
to convenience and are applicable in limited situations, two parameter analysis is quite sufficient in
most cases. This last point is critical, since any method that seeks to supplant flow cytometry must
have the ability to characterize at least 2 cell surface markers simultaneously.
Analysis of cell populations by flow cytometry is not a trivial process and requires highly
trained personnel as outlined above. Both single parameter and multiparameter analysis can be
performed. If data is analyzed as histogram plots of fluorescence of a single marker versus cell
number, then one parameter analysis is being performed. Analyzing two such histograms of a
single gated cell population could then be referred to as simultaneous single parameter analysis.
An example of simultaneous single parameter analysis would involve the use of such plots to
identify cell surface expression of both the B-cell marker CD20 and the light chain kappa.
Analysis of the binding of each set of antibodies is independent of the other. In multiparameter
analysis, the binding of the two antibodies are linked and are not independent. Analytical methods
require the binding of both antibodies simultaneously brought together in a single histogram such as
fluorescence 1 versus fluorescence 2. Characterization of the target cell population is best
performed by analysis of this fluorescence 1 vs. fluorescence 2 plot and analyzing the binding
characteristics of each of these antibodies together. This decreases the possibility of an error that
would incorrectly analyze two overlapping cell populations as a single cell population.
Finally, with the limited exception of DNA ploidy analysis, characterization of solid
tumors and non-hematopoietic tumors is quite limited by flow cytometry. Often there are not well
developed protocols for developing cell suspensions. In addition, tumor cells may be delicate and
may not survive processing. In addition, many markers used for solid tumors such as vimentin or
smooth muscle actin are intracytoplasmic antigens and may be difficult to assay by flow cytometry.
In addition, most available markers for these other tumors are not specific markers for the tumors
and many normal cells, including ceils present in the background of the available sample, may be
strongly positive for the same markers. Therefore, interpretation of these kinds of samples without
specific morphologic correlation is hazardous at best.
An object of the invention is to provide a cheaper, more accessible method for single
parameter and multiparameter analysis of cell populations. This analysis is not limited to just cell
surface markers but also optionally includes identifying active receptor sites on cell surfaces, loss
of cell surface proteins, intracellular proteins, and intracellular nucleic acid sequences. One of the
features of this invention is that the target cell population is being analyzed by preserving
morphologic characteristics of the cells for analysis. In addition, it is also possible to count events
to obtain specific cell numbers in relation to specific sample volume. Due to the many preparatory
steps of flow cytometry, obtaining absolute cell numbers is not possible - only percentages of cells
analyzed.
SUMMARY OF THE INVENTION
A method of characterizing cells is provided, comprising the steps of a) providing a
suspension of cells in a liquid medium, said cells including first cells, b) adding to said suspension
a group of substantially identical first beads, each of said first beads being coated with a binding
substance or being magnetic such that each first bead is adapted to bind to a first cell, c) incubating
said first beads in said suspension for a period of time effective to permit said first beads to bind to
said first cells to form first bead-first cell complexes, each first bead-first cell complex comprising
a first bead and a first cell, d) separating said first bead-first cell complexes from said suspension
by Filtration, and e) examining said separated first bead-first cell complexes and characterizing said
first cells. A kit is also provided, comprising at least one group of substantially identical
first beads, each of said first beads being coated with a binding substance or being magnetic such
that each first bead is adapted to bind to a first cell, said kit further comprising a set of instructions
effective to instruct a technician in now to use said first beads to perform single parameter or
multiparameter analysis on a suspension containing first cells. An apparatus for performing single
parameter or multiparameter analysis on a suspension of cells is provided. The apparatus
comprises a sample loader, a plurality of reaction chambers, and a filtration chamber.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a schematic illustration showing a cell bound to an antibody which is bound to or
coated on a bead.
Fig. 2 is a schematic illustration showing a number of cells bound to a bead.
Fig. 3 is a schematic illustration showing a number of cells bound to a bead in the center,
and five smaller beads bound to five of the cells.
Fig. 4 is a schematic illustration of an automated device for performing phenotypic or
immunophenotypic analysis in accordance with the present invention.
Fig S. is a schematic illustration of a single slide for use with the automated device of Fig.
4.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION
As used herein, when a preferred range such a.s 5-25 is given, this means preferably at
least 5 and, separately and independently, preferably not more than 25. The cells herein are
preferably human cells. If a first group of cells does not include members of a second group of
cells, and the second group of cells docs not include members of the first group of cells, the two
groups do not overlap. "Visually distinguishable" includes visually distinguishable via light
microscopy. Quantitate includes to estimate or enumerate or count the number of. Phenotyping
includes immunophenotyping and genotyping.
The invention uses beads. As used herein, beads means small particles or support
surfaces, preferably microspheres, more preferably plastic microspheres, more preferably
polystyrene microspheres (also referred to as latex beads or spheres or microspheres), which have
preferably been coated with a binding substance or which are magnetic. As used in the claims,
"first beads" includes beads which have been coated with a binding substance or which are
magnetic. The bead may be any solid support surface or particle that can be suspended in an
appropriate solution. Preferred beads are available as polystyrene microshperes from Bangs
Laboratories, Fisher, IN. The bead sizes are preferably greater than 5 microns diameter,
preferably 5.S-I0.3 microns, less preferably at least 5.5 or 10 or 12 microns and preferably not
more than 12, 15, 20 or 30 microns diameter, far less preferably less than 5 microns, such as at
least 1, 2 or 3 microns diameter. 5.5 and 10.3 micron beads are preferred. The beads can also be
colored, such as red or blue, less preferably green, purple, orange, brown, yellow, or any other
color. The beads are preferably coated with a binding substance, such as antibodies or
immunoreactive proteins, or any molecule that can bind to, or interact with a cell surface in such a
way as to bring the cell and the bead into contact or adherence with each other or to bind with each
other; alternatively, the head can contact or bind with the cell surface through electrostatic charge
interactions or magnetic interaction; aH of these concepts being covered by the terms "binding to"
or "bind to". When a bead binds to a cell, it forms a bead-cell complex. In the invention the cell-
bead interaction forms a targe enough complex to inhibit the passage through a filter containing
pores of appropriate dimensions. The filters are preferably sized and selected such that unbound
cells and beads will pass through the pores but bound cell-beads do not. These complexes are then
transferred to a glass slide and stained with a variety of stains so as to render the complexes visible
by routine, microscopy. The complexes and cells are examined and the cells are characterized.
Examples of binding substances or reactive substances that may be used to coat the bead surface
include, but are not limited to: antibodies to specific cell surface proteins, small molecules that bind
receptors or other cell surface molecules such as IL-2 or GM-CSF, avidin, biotin, or beads may
remain uncoated in suspension that can interact by other means with cells. The antibodies that can
be used are those known in the art. Many such antibodies are available from commercial
companies, such as Zymed Inc., South San Francisco, CA and Dako Corp., Carpinteria, CA.
Beads or micrpspheres can be made from a variety of substances including gold, ferritin,
polyacrylamide, or polystyrene. The latter is among the preferred substances as beads can be made
precisely to any size specification and can be uniformly conjugated to both molecular linker arms
and reactive binding substances. Polystyrene microspheres (also known as "latex microspheres")
may be prepared by methods known in the art which are incorporated by reference herein.
Binding substances that can be used include monoclonal antibodies, polyclonal antibodies, antibody
"cocktail" mixtures, antibody fragoents (such as Fc portions or Fab or Fab' fragments in either
monovalent or divalent forms), small molecules that bind specific cell surface receptors, covalent
and non-covalent linkers, and indirect adherence such as utilizing electrostatic or magnetic or
paramagnetic attraction.
The prior art includes U.S. Pats. 5,554,505; 5,348,859; 5,340,719; 5,231,005; 5,260,192;
5,338,689; 5,256,532; and 5,501,949, the entire contents of which are incorporated herein by
reference. These patents include discussions of using certain nucrospheres or beads for
identification of cells. It is known in the art how to provide a suspension of cells in a liquid
medium for analysis.
A second feature of a preferred embodiment of the present invention is that it concentrates
cells by using an appropriate filter without added manipulation of the cell suspension by cell lysis
or added incubation steps of submicroscopic paramagnetic microspheres. The filters to be used in
the invention can be any of those known in the art, such as gynecological filters from Cytec Corp.,
Boxborough, MA. The filters preferably have a pore size larger than the beads being used so that
all or most or substantial amounts of unbound beads and unbound cells pass through, but the pore
size is preferably small enough so that all or most or substantial amounts of beads bound to cells
are trapped on the filter, such as the filter pore size being about 1, 2, 3, 4, 5, 6, 8, 10 or 12
microns larger than the bead size. Preferred filter pore sizes include 10-15, less preferably 7-20,
7-30 or 7-40 micron pore sizes. Alternatively the filter pore sizes can be at least 15 or 20 microns.
The filler is preferably mounted on a solid support, such as at the end of a tube through which the
suspension can drain.
A cell suspension is preferably prepared from a peripheral blood sample, a bone marrow
aspirate, a fine needle aspirate, a lymph node biopsy, or a body site specimen. In the method
described herein, single parameter, simultaneous single parameter, and true multiparameter analysis
is possible which compares to the level of sophistication of analysis possible by flow cytometry.
Beads that can be easily distinguished from each other optically either by size, color, or both can
be added to a cell suspension either simultaneously or sequentially. Positive binding by the target
cell population results in a bead-ceil complex that has a significantly larger physical size than either
unbound cells or beads. These complexes can be then easily concentrated and separated from the
rest of the solution using an appropriately sized filler containing pores of sufficient size to let
unbound cells and beads to pass through while complexes remain on the filter. The method may
also be used in reverse, in that abnormal cell populations may fail to bind beads while normal cells
bind strongly. An example of this latter method can be found with the myelodysplastic disorders
(MDS), which currently cannot be diagnosed by flow cytometry with any degree of reliability.
Normal human myeloid cells strongly express surface markers such as CD1 lb, CO13, CD1S,
CD 16 and CD33. However, in MDS, these cell populations lose expression of these markers.
However, as normal cells degenerate from prolonged storage or poor specimen handling such as
temperature extremes, which may occur in specimen transport, they also lose expression of these
markers. Flow cytometry cannot distinguish between these two conditions. However, degenerated
cells are easily recognized morphologically from the dyspiastic cells of MDS. Loss of binding by
beads coated with antibodies to these markers could easily be identified (with a slide made of the
cells passing through the filter as well as those trapped on the filter). Therefore, this method is the
first easily available method to diagnose MDS, heretofore only diagnosable in those minority of
cases showing abnormal cytogenetics or persistent hematologic abnormalities after prolonged
clinical follow up. As an example of MDS analysis, one can look at a peripheral smear. If the
cells are degenerated, get a new sample. If the cells are not degenerated, incubate the cell
suspension with large beads coated with anti-CD13. Then add small beads coated with anti-CD 15
and let react. Then filter (can be small pore size to trap both bound and unbound cells, or large
pore size to trap bound cells only, in which case unbound ceils are collected from what went
through the filter). If the result is lots of complexes like Fig. 3 and few unbound cells, this
indicates normal cells. If there are few bound cells and many unbound cells, this suggests MDS.
Immature cells also have weak binding, but this can be seen morphologically. The same procedure
can be done with CD1 lb and CD16.
One can also count beads trapped on the filter prior to transfer to the glass slide. Using
methods such as light scattering, reflectance, fluorescence, or electrostatic field changes, the
number of beads trapped on the filter can be counted. An average number of ceils bound to each
bead can be obtained and an estimate of the number of cells in the original sample volume
obtained.
With reference to Fig. I there is shown, not to scale, a bead 2, such as a polystyrene
microsphere. which has coated thereon and bound thereto a binding substance 4 such as an
antibody. There is also a cell 6, such as a target cell, which has a cell surface marker 8. The
binding substance 4 or antibody binds to the cell surface marker 8 on the target cell 6. Fig. 2
illustrates how this kind of reaction may appear on a glass slide; a group of cells or target cells 12
have bound to a bead 10. This shows single parameter binding of cells to beads. The ratio of
beads to cells should be adjusted properly for effective results. The actual number of cells binding
the bead is variable, ranging from a single cell to numerous cells crowding the bead's surface.
With reference to Fig. 3 there is shown a large bead 14 coated with a binding substance
which has bouod to eight cells 16, 18, 20, 22. Small beads or different colored beads 24 coated
with a different binding substance have bound to the cells 22 but not to the cells 16, 18, 20. This
provides positive identification of target cells 22. This illustrates multiparameter analysis. Cells 22
is a subset of cells 16, 18, 20, 22. A variable number of beads 24 can bind to each cell 22. la
some cases each cell bound to bead 14 will be bound to one or more beads 24, or each cell bound
to bead 14 may be unbound to small beads. Note that different kinds of cells may bind to the large
bead 14 that can in some cases be distinguished morphologically. Preferably the large bead 14 is
added first to the cell suspension so that a plurality of cells can bind to its surface. Then the small
beads 24 are added to bind to the periphery of the complex. Alternatively small beads 24 can be
added first or small beads 24 and large beads 14 can be added simultaneously. The order of
addition is dependent in large part upon the relative concentrations and surface areas of the beads
and the cells. For example, you would not want to add beads 14 or 24 in such concentrations that
they completely cover or obscure the surface area of the target cells and thus prevent access thereto
by the other beads. Preferably there is an excess of target cells to fully coat the bead. Optionally
the suspension can be filtered after the first complex is formed, to trap the first complex and
resuspend it before the second beads are added. Thus a group of complexes can be filtered and
resuspended before a subsequent set of beads is added; this can lead to more certain and distinct
results by removing materials which would provide interference. The beads may be distinguishable
in size or color or both. Further levels of multiparameter analysis can also be carried out, such as
by adding to Fig. 3 another set of different sized or different colored beads which would bind to a
first subset of cells 22 but not the remaining cells 22, thus providing positive identification of said
first subset of cells 22. In this manner subsequent or additional levels of multiparameter analysis
can be carried out.
There is a wide variety of available beads that can be used, and those selected would
depend on the specific application. In multiparameter analysis beads that can be easily
distinguished by either size or color are preferable. For example, two sets of colorless beads sized
10 and 5 microns respectively can be used to isolate a population of B cells using 10 micron beads
coated with an anti-pan B cell antigen such as CD 19 and 5 micron beads coated with anti-kappa.
Multiparameter analysis that cannot be easily mimicked by flow cytometry is available by a minor
variation of this example. Colorless 10 micron beads are used to bind B cells by using anti-CD 19
coated beads. 5-micron colorless beads are coated with anti-kappa while dark blue 5-micron beads
are coaled with anti-lambda. Similarly, a blast cell population can be analyzed using anti-CD34
coaled 10 micron beads and anti-CD 19 coated colorless S micron'beads. Colored 5-micron beads
coated with anti-CD 13 are simultaneously added fur rapid characterization of most blast ceil
populations.
Preferred methods:
1) Substantially identical beads are purchased commercially precoated with strepavidin (Bangs
Laboratories, Fishers, IN). A small quantity is suspended in any buffered salt solution such as
phosphate buffered saline or commercially available antibody diluent. The beads are incubated with
biotinylated goat anti-mouse antibodies for 30 minutes (however, any biotinylated anti-allogeneic
antibody may be used). The suspension is centrifuged and the supernatant drawn off. The
incubation is repeated two times to ensure coating of as much of the available surface area of the
beads as possible. The beads are then washed three times using the same buffer. The suspension
is then incubated with specific mouse anti-human antibodies for I hour (or any non-biotinylated
anti-allogeneic antibody specific for the target cell population may be used). The suspension is
again washed three times and diluted to the desired concentration. The resulting suspension can be
refrigerated at 4 degrees Centigrade until use. Alternatively, biotinylated primary antibodies may
be used without the use of secondary antibodies. The beads produced by this technique are
substantially identical.
2) Beads are precoated with anti-Fc receptor antibodies (Bangs Laboratories, Fishers, IN)
such as goat anti-mouse IgG Fc receptor antibodies. These beads can then be suspended in a
solution of antibodies which would spontaneously bind to the anti-Fc receptor sites on the beads.
in the example cited above, mouse anti-human antibodies would be bound to the beads followed by
appropriate washing steps similar to that described above.
3) Binding substances such as any protein, peptide, or nucleotide sequence may be bound by
other chemical or specific binding methods. For example, polystyrene microspheres are "naturally"
left coated with sulfate surface groups after manufacture. These ligands can be used to link
proteins and peptides directly to the surface of the beads. Examples of such functional surface
groups that can be coated on the surface includes, but is not limited to. aldehyde, aliphatic amine,
amide, aromatic amine, carboxylic acid, chloromethyl, epoxy, hydrazide, hydroxyl, sulfooate, and
tosy (toluene sulfonyl) reactive iigands. These can then be used in turn to link peptides, proteins,
oligonucleotides, and other biochemical Iigands to the surface. These Iigands or binding substances
would in turn be used to bind specific sites on cell surfaces which would link the cell to the surface
of the bead. For example, a small molecule such as the hormone 1L-2 could be used by one of the
above methods to coat beads with the intention of binding IL-2 receptor sites (CD25) on cell
surfaces. This could be used to bind cells such as T-cells, monocytes, and neoplastic cells such as
hairy cell leukemia.
Other methods:
Submicroscopic paramagnetic microspheres (preferably less than 1 micron «n diameter) are
bound to any reactive biomarker of interest. The binding that is used could be any of the above
methods. Cells are then permeabilized and fixed using a vanety of detergents and weak fixative
solutions such as 1 % paraformaldehyde. Alternatively a number of commercially available
permeabilizing kits are available for this purpose such as IntraStain (Dako Corp., Carpinteria, CA).
The reactive biomarker, such as antimyeloperoxidase antibodies, anti-terminal deoxytidyl
transferee antibodies, or specific RNA or DNA probes, is then incubated with the cell suspension.
The biomarkers and paramagnetic particles get inside the cell and. for example, the probe binds to
the intracellular target. The cells are then washed and resuspended in a suitable buffer such as PBS
or RPMI. The suspension is then incubated with magnetic beads or microspheres of a size or color
easily visualized, such as I to 20 or 3-15 or 5-10 or 10-20 microns. The magnetic beads bind to
the cell surface, but cannot cross the membrane, to create a cell-bead complex that is easily trapped
such as via filtration.
In one example, abnormal Masts in a bone marrow suspension can be permeabilized and
incubated with anti-myeloperoxidase antibodies bound to submicroscopic paramagnetic
microspheres. The suspension is then washed three times in buffered salt solution and resuspended
and incubated with large magnetic beads of a preferred size of 5-15 micron diameter to create cells
bound to large beads.
In another example, specific DNA sequences (probes) are bound to submicroscopic
paramagnetic microspheres using methods such as avidinated microspheres and biotinylated probes.
Cells from a patient with chronic myelogenous leukemia are permeabilized and incubated with
probes binding to the specific bcr-abi translocation Sat is diagnostic for the disease. The
suspension is then washed and incubated with large magnetic beads of a preferred size of 5-15
micron diameter to create cells bound to large beads.
Detection and analysis:
The cell-bead complexes (cells bound to beads) provided or obtained as described above
are then passed through a solid support filter having a porosity of sufficient size to allow unbound
cells and beads to pass through. The suspension is passed through the filter using a variety of
acceptable methods which includes gravity, suction (applied vacuum), positive pressure on the fluid
side, or wicking the fluid through the fitter using a porous absorbabte material such as gauze pads.
Various devices that can be used include pistons, syringes, or suction methods to create a negative
pressure to pass fluid through the filter. In a preferred embodiment, a single solid filter with a
pore size of 10-15 microns is used. Cell-bead complexes remain trapped on the filter and the layer
is then transferred to a glass slide by direct contact with the slide and applying gentle pressure.
The resulting slide preparation can be stained using a variety of commercially available stains such
as bematoxylin and eosin, Papanicolau stain, or any Romanowsky stain. In a preferred
embodiment, the cells remain suspended in a compatible buffer such as PBS, RPMI, or
commercially available antibody diluent and the resulting slide is stained with Wright-Giemsa stain.
Alternatively, cells may be suspended in ethanol or a commercially available fixative such as
Cytolyte (Cytyc Corp., Boxborough, MA). The resulting slide is then stained with Papanicolau or
hematoxylin and eosin stains. The complexes are examined and the cells are characterized under
routine light microscopy.
The invention can be used to perform single parameter analysis correlated with
morphology, simultaneous single parameter analysis, or multiparameter analysis. In single
parameter analysis, (depicted in Figs. 1 and 2) a single bead type is added to a suspension of cells
in a liquid medium so that after filtration the slide is provided with an enriched single cell
population. This is useful as a simple screen to determine if a cell population has a particular
characteristic such as distinguishing monocytes from monocytoid B lymphocytes as cited in
Example 1 below. In this configuration, cells bind to beads and are visible on the glass slide for
analysis. Alternatively, a B cell population can be assayed for expression of kappa or lambda by
using two separate slides or slide wells each of which contain a single bead type (anti-kappa or anti-
lambda). Another variant of this analysis is to add simultaneously to the cell suspension two
different bead types, one anti-kappa and a second anti-lambda. This is an example of simultaneous
single parameter analysis since binding of each bead type is independent of the other but the results
are analyzed together. An analogous situation occurs in flow cytometry analysis when fluorescence
is displayed vs. cell number to obtain a single histogram. In kappa and lambda analysis, a
monoclonal population can only be detected by simultaneous analysis of both histograms and
looking for single peaks of fluorescence. Finally, multinarameter analysis can be performed by
linking detection of two different characteristics so that analysis is performed together. In this
case, binding of one set of beads occurs, followed by a second and optionally more sets of beads
(see Figure 3). Analysis looks for simultaneous binding of more than one set of beads to the target
cell population (as depicted in Example 2 below).
The invention can be used to detect abnormal loss of binding when strong binding would
be expected. For example, normal myeloid cells such as mature granulocytes and monocytes in the
peripheral blood would-be expected to strongly express the surface markers CD 13, CD33, CDUb,
and CD 16. In a bone marrow sample there would be a continues range of increasing expression of
these markers as the cell matures. However, cells showing abnormal maturation, as seen in
myelodysplasia, would show diminished expression of these marker;;. This phenomenon has been
previously described by Davis, et al. and can be seen in flow cytometry analysis as abnormal
patterns of expression on appropriate histograms. However, a similar loss of expression is seen
when normal cells die and degenerate as occurs in specimen mishandling or aging. Since
morphologic correlation is less than optimal by flow cytometry, the phenomenon has limited
diagnostic usefulness, particularly when the specimen has been transported long distances. In the
present invention, cells can be visualized on the glass slide to confirm their viability. Normal cells
would strongly bind beads coated with these markers but there would be decreased binding of beads
in cells with myelodyspiasia. In the low grade myelodysplasias such as refractory anemia and
refractory anemia with ringed sideroblasts, there are often no objective diagnostic criteria for
confirming the diagnosis. Current slate of the art in such cases requires prolonged follow up and
diagnosis by exclusion of other possible entities such as ethanol toxicity or megaloblastic anemia
from vitamin B12 or folate deficiency. The invented method provides a much needed positive
diagnostic test.
A complementary detection method is that prior to transfer of the cells to a glass slide, the
filter is gently rinsed and scanned using a light beam of either a white light beam or a specific
wavelength to correspond to the excitation wavelength of fluorescent beads. The number of events
is counted electronically and the cells are then transferred to a glass slide and stained. The average
number of cells per microsphere is then obtained manually and an estimate of the total number of
target cells in the sample can be estimated (assuming that a known volume of sample is used).
Preferred applications:
1) Single parameter analysis of tumors and other specific cell populations. A suspected tumor
with a known immunophenotype can be analyzed to confirm the presence of a single marker as
outlined in Examples 1 and 3 below. This is most useful in settings where a single issue regarding
cell phenotype needs to be settled. In Example 1 below, knowing that the abnormal ceil population
is of B cell origin is sufficient information to proceed with further studies, since this suggests (but
does not prove) malignancy. In Example 3 below, knowing that the lymphoid population is of T
cell origin suggests that the patient has a reactive infiltrate rather than a malignant infiltrate. If this
assay had been clinically available in both of these unusual cases, the results of the simple study in
Example 1 would justify further expense of additional evaluation. The results of Example 3 justify
not performing flow cytometry and proceeding to treatment for meningitis. Other applications of
these kinds of analysis can be useful in other kinds of tumors such as MN/CA9 screening for
cervical cancer, identifying specific tumor types in malignant infiltrates such as melanoma (using
markers such as HMB-45), or identifying micrometastic disease in lymph nodes and bone marrows.
In addition, single parameter analysis can be used in genetic phenotypic and genotypic analysis.
For example, a peripheral blood sample can be permeabilized and treated with a specific probe to
the bcr-abl translocation. The probe can be labeled with paramagnetic submicroscopic
microspheres. The cells can (hen be treated with large, magnetic beads to identify the presence of
the translocation that would be diagnostic of chronic myelogenous leukemia. Alternatively, a
similar method can be used to identify the presence of intracellular proteins or RNA sequences
using appropriate antibodies or nucleotide sequences, for example, the expression of the
intracellular protein terminal deoxyribonucleotidyl transferase (TdT) using an antibody also labeled
with paramagnetic microspheres and detecting the reaction using large surface magnetic beads.
Finally, the use of CD64 expression has been proposed as a rapid diagnostic test for clinically
significant acute inflammatory reaction (Lab. Hematol. 1995; 1:3-12). For reasons described
above, flow cytometry is too expensive and difficult to use as a screening procedure for common
conditions. The invented method allows rapid, inexpensive single parameter analysis for CD64
expression in peripheral gramilocytes.
2) Simultaneous single parameter analysis is where there is simultaneous analysis of markers
that are independent of each other. Most commonly, this is used in a B cell lymphoid population to
determine expression of either kappa or lambda light chain restriction by expressed surface
immunoglobuiins. This can either be done by using similar beads as used in two separate glass
slides analyzed simultaneously or by using a single slide using two sets of beads which can be
easily distinguished based on size, color, or both. This is extremely useful as an inexpensive, rapid
screen for B ceil monoclonality. Other useful types of simultaneous single parameter analysis are
in the setting of a malignant tumor of unknown origin where a cell suspension can be analyzed,
either by using multiple separate slides or a single slide containing multiple sets of beads that can
be distinguished by size, color, or both. In this example, these sets of beads typically include
beads marking for CD45 (leukocyte common antigen), HMB-45 (melanoma), and a general
cytokeratin marker (often AE1 and AE3 cocktail for epithelial tumors). A third type of this kind of
analysis is to screen a population of lymphocytes to determine whether this population is composed
of B cells, T ceils, other cells, or any combination of these types.
3) The invention also includes multiparameter analysis where expression of markers are
analyzed in conjunction with other markers. A simple, but common, example of this kind of
analysis is depicted in Example 2 below. In Example 2, the positive binding reaction by the anti-
CD20 coated beads which isolates the B cells is linked to kappa or lambda light chain expression.
Multiparameter analysis enhances analysis since correctly identifying certain cell populations
requires logical association of multiple subsets of markers. A case of acute leukemia serves as a
useful example of this kind of analysis. Morphologic examination is one of the best methods for
identifying the abnormal blast cells, but it does not characterize the kind of blasts present.
Combining morphologic analysis with the present invention would yield the following typical kind
of analysis. Anti-CD34 coated beads are combined with anti-HLA-DR coated beads to confirm
expression of both of these markers in the malignant cell population. Positive expression of both of
these markers supports the diagnosis of acute leukemia. The cells can then be analyzed with anti-
CD13 and anti-CD33 coated beads »n conjunction with anti-CD19 and anti-CD2 coated beads to
determine if the cells are myeloid or lymphoid in origin. If they bind to CD 13, CD33, or both,
this confirms the myeloid derivation of the cells. The cells can also be analyzed with anti-CD15,
anti-CD 14, anti-CD56, anti-CD7, and anti-CD4 to determine subtype (myeloid, monocytic, or both)
and to yield prognostic information. Of particular interest is successful analysis of acute
promyeiocytic leukemia (FAB subtype M3). Analysis of this tumor type by flow cytometry is
fraught wilh errors and the tumor can be missed since it is composed of maturing myeloid cells.
Using the present invention, morphologic analysis would confirm the presence of excess numbers
of promyeiocytic cells. In addition, the promyelocytes would usually be HLA-DR negative and
could also be analyzed for the transiocation of chromosomes 15 and 17 (t(15;17)) which is
diagnostic of the disease. This kind of analysis is particularly useful in the microgranular variant
of the disease in which the cells may resemble monobtasts. Monocytic leukemias can also be
analyzed for additional monocytic markers such as CD36. Similar kinds of analyses can be
performed for other hematologic malignancies, other tumor types, and other specific cell
populations. In addition, the method can be used in reverse to offer a diagnostic test for
myelodysplasia. Normal myeloid cells strongly bind the myeloid markers CD1 lb, CD13, CD16,
and CD33. Among the changes seen in myelodysplasia, is decreased expression of these markers
by flow cytometry. However, degenerating cells, as occurs in excessive sample age, temperature
extremes, or other forms of specimen mishandling also causes decreased expression of these
markers. Since morphologic correlation with flow cytometry is so poor, this form of analysis has
not gained significant clinical acceptable since flow cytometry cannot reliably distinguish between
degenerated normal cells and myelodysplastic cells. In the invented method there is excellent
morphologic correlation, and trained observers will easily recognize degenerated cells. Therefore,
normal cells can easily be distinguished from dysplastic cells, as normal cells will avidly bind beads
coated with antibodies to these markers and dysplastic cells will not.
Another similar application can be used for analysis of breast cancer to determine
prognostic factors such as Her2/neu overexpression. Current state of the art utilizes primarily
immunohistochemistry to localize actual tumor from surrounding breast tissue by visual methods.
Her2/neu cytoplasmic membrane expression is estimated by the observer visually on a scale
expressed as 0+ positive (no expression) to 4 + positive (strongest possible expression). There are
no objective quantitative methods to estimate the level of Her2/neu overexpression. Alternatively.
Her2/neu expression can be more objectively estimated by using fluorescent in-situ hybridization
(FISH) which labels each gene copy wilh a fluorescent dot. The number of gene copies in each
cell can be estimated by merely counting the dots within the nucleus of each cell. However,
because cells cannot be easily counter-stained and observed, it is difficult to tell a malignant breast
epithelial cell from an admixed benign one or even a stromai cell from the breast supporting
matrix. Therefore, analysis by FISH has less acceptance in the clinical setting. More recently,
Her2/neu expression can be performed by flow cytometry, however, like FISH there is no method
for evaluating whether the analyzed cell is a malignant cell or a benign one. Using multiparameter
analysis as described in the present invention, epithelial cells in a cell suspension can be
distinguished from stromai cells by using large (10 micron) beads coated with anti-cytokeratin
antibodies. Only epithelial cells would bind to this bead. Small S micron beads coated with an
appropriate anti-Her2/neu antibody is then added to the mixture and the suspension filtered.
Her2/neu expression can be analyzed objectively by several methods. In one method, the filter
itself can be analyzed to determine the quantity of 5 micron beads present on the filter by using
methods such as fluorescence (if the 5 micron beads are fluorescent), electrostatic assessment, or
other of a variety of known counting methods. In an alternative method, the suspension is
transferred to a glass slide after filtration and the slide stained. Benign cells can be distinguished
from malignant ones by morphologic assessment and the average number of beads binding to
malignant cells can be estimated. This can either be performed manually by the observer or in a
semi-automated manner using an electronic visual analysis to count the number of beads bound to
each cell identified by the observer as malignant.
4) Signal amplification of weakly expressed antigens. One of the major advantages of flow
cytometry is its ability to detect weakly expressed antigens on the surface of cells. Many antigens
fall under this category and cannot be easily detected using alternative means such as routine
inuminostains using standard colon metric detection methods such as diaminobenzadine (DAB).
This problem in immunostains has been partially overcome using signal amplification methods such
as tyramide signal amplification which is commercially available such as the Catalyzed Signal
Amplification kit (Dako Corp., Carpinteria, CA). In the method, the primary antibody is
conjugated to peroxidase enzyme (usually horseradish peroxidase or HRP) and oxygen free radicals
are generated. In the presence of tyramide, the tyramide molecules themselves become free
radicals and are short lived, highly reactive species. They readily conjugate to nearby molecules
and are fixed in the immediate area of the primary antibody. The signal amplification derives from
the ease in which tyramide is conjugate either to a fluorescent molecule or peroxidase. This added
peroxidase is used to generate additional DAB signal and thus the signal is amplified. This signal
amplification technique can also be applied to the invented method described herein. In one
example, primary antibodies are conjugated to HRP to generate biotinylated tryamide free radicals
as per the manufacturer's directions. Avidinated beads then readily and spontaneously bind to the
cell surface at the appropriate sites. An alternative method uses submicroscopic beads that are
invisible by routine light microscopy which are coated with the antibody of interest that also have a
peroxide free radical generator such as HRP bound either to the antibody or to the surface of the
bead. Biotinylated tyramide free radicals are generated as per the manufacturer's directions and
then the cells are washed (or filtered) and treated with avidinated large beads that are easily visible
by light microscopy (typically beads in the 5-20 micron size range). This method of signal
amplification greatly enhances otherwise weak binding of beads when only rare antigens are present
on the cell surface. Single amplification can also be achieved using (1) the dual-labelled Envision
polymer system available from Dako Corp., Carpinteria, CA. or (2) the mirror image
complimentary antibodies technique, a kit for which is available from The Binding Site Company,
Birmingham, England.
5) An alternative method of multiparameter analysis can be performed by first using a single
set of beads to isolate the target cell population. The second parameter can then be detected by
using routine or conventional inununohistochemical techniques such as immunflouresence,
colorometric methods such as peroxide reduced DAB or alkaline phosphatase methods, or
immunogold/silver enhancement. This second antibody detection system can be applied either in
the cell suspension or after the slide is made but before it is stained. The choice of method and
detection method would be dependent on the desired stain in the final product and the particular
antibody to be used. Since this method bypasses fixation and processing used in paraffin embedded
tissue sections, antibodies that cannot be used in these paraffin can be used here such as CD 10,
CD2, or CD19.
The following Examples further illustrate various aspects of the invention, including single
parameter and multiparameter analysis.
Example 1
A 30 year old man presented with pancytopenia and splenomegaly. Examination of the
peripheral smear confirmed the pancytopenia. In addition, scattered cells were present that showed
bland cytological characteristics, with a monocytoid appearance. The nuclei of these cells were
round to oval, with a single intermediate nucleolus. There was abundant blue-gray cytoplasm that
showed numerous cytoplasmic projections. A bone marrow examination revealed a hypocellular
aspirate with similar cells present. Small clusters of abnormal cells were present on the core
biopsy. A buffy coat sample of the peripheral smear was suspended in anti-CD20 coated 10-
micron colorless beads to distinguish the abnormal cells from monocytes. The suspension was
passed through an appropriate filter and the ceils were then transferred lo a glass slide and stained.
A schematic of the resulting slide preparation is demonstrated in Figure 2. Positive binding of the
abnormal celt population to the 10-micron beads was a suspicious finding and suggested an
abnormal B cell population. Flow cytometry performed on the bone marrow aspirate revealed a
monoclonal population of monocytoid B cells expressing CD19. CD11c, CD103. and kappa light
chain restriction confirming the diagnosis of hairy cell leukemia.
Example 2
A 68 year old man with a known history of chronic lymphocytic leukemia (CLL) presented
for routine follow up examination. Clinical examination revealed that the patient had a peripheral
white cell count of 435,500 cells/ml (normal range 4,300-11,000 cells/ml) which included 87%
lymphocytes. Morphologic examination of the peripheral blood smear revealed predominantly an
abnormal population of small lymphocytes with a small but significant population of large
transformed cells. A suspension of cells in a liquid medium was provided. This sample was
analyzed using anti-CD20 coated 10-micron beads, anti-kappa coated colorless 5-micron beads and
anti-lambda coated colorless 5-micron beads in two separate tubes. In the procedure, the same
sample was placed into each of 2 tubes. To each tube was added anti-CD20 coated 10-micron
beads. These strongly bound the B cells. The question then was whether the B ceils were kappa,
lambda or a combination of both. Therefore, the 5 micron anti-kappa beads were added to the first
tube and the 5 micron anti-lambda beads were added to the second tube. The results were then
analyzed after filtering and placing on a glass slide. The cells strongly bound to the 10-micron
beads and showed no binding to the anti-lambda beads and scattered binding to the anti-kappa beads
(ie, like Fig. 3, except only 1-2 small beads per complex). These results are typical of CLL since
this tumor strongly expresses CD20 but weak light chain restriction when analyzed by flow
cytometry. As an alternative procedure, the 5 micron anti-kappa beads could be red and the 5
micron anti-lambda beads could be blue. The procedure could still be in 2 tubes as described
above, or the kappa and lambda beads could be added simultaneously to the first tube. Analysis of
this latter result would show a complex like Fig. 3 with blue only around the periphery (indicating
monoclonal lambda), rod only around the periphery (indicating monoclonal kappa), of a
combination of red and blue around the periphery (indicating polyclonal B cells).
Example 3
A 19 year old man presented with headache and stiff neck to the emergency. His
evaluation included obtaining a sample of cerebral spinal fluid for which emergency pathologist
evaluation of the fluid was requested to rule out the presence of "blasts". Evaluation showed a
relatively uniform population of small lymphocytes, and a diagnosis of viral meningitis was
suggested. The patient's physician requested flow cytomelry to completely rule out the possibility
of malignancy. Since excess fluid was available, a small sample was treated with anti-CD20 coated
10-micron beads and anti-kappa and anti-lambda coated 5-micron beads in two separate tubes using
essentially the same procedure as described in Example 2 above. The majority of cells did not bind
to either the anti-CD20, anti-kappa, or anti-lambda beads, suggesting that the lymphoid population
was composed predominantly of T cells. Flow cytometric analysis received two days later
confirmed approximately 60% T cells and 40% B cells wilb normal T cell subsets and polytypic B
cells consistent with viral meningitis.
A major advantage of the invention is that analysis of cell populations can now be
performed by simple inspection of the glass slide by any physician or technologist. This kind of
analysis can be used on any type of ceil population bearing specific cell surface markers and in a
wide variety of conditions {lymphoma is one example). Malignant clones from patients with acute
leukemia can be similarly analyzed (using different types of markers), as can cell populations from
patients with acquired immune deficiency syndrome. Finally, as tumor markers for solid
neoplasms become available, this kind of analysis can also be performed in a similar fashion. For
example, the new MN/CA9 antibody appears to be specifically expressed by dyspiastic and
malignant uterine cervical squamous cells. Since these cells may be suspended in a sea of normal
ceils, they may be difficult to identify even by routine inununohistochemistry. This method of
analysis may both identify these cells and enrich a cytological preparation for them so that they can
be more easily analyzed.
The present invention also provides a kit for practicing the invention. The kit contains one
or more sets of beads as described above. Each set of beads is preferably in a container such as a
sealed test tube. In some cases of simultaneous single parameter or multiparameter analysis, two
or more sets of beads can be premised, but typically they are kept separated. The kit also
preferably contains one or more appropriate filters as described above and preferably a set of
instructions.
The methodology described herein can be automated and condensed. An example of a
semiautomated device 25 for the performance of this kind of analysis is depicted in Figure 4. A
sample is prepared to make a cell suspension. The sample is then loaded into the machine 25 in
the sample loader 26 and the machine 25 is programmed for the kind of analysis desired
(lymphoma screen, acute leukemia analysis, myelodysplasia, etc.). The sample is divided into the
appropriate number of reaction chambers 28 (for example, 2, 4, 6, 8. 10 or 12) and a
preprogrammed number of bead sets (for example, 1, 2, 3, 4, etc bead sets) added sequentially or
simultaneously to each reaction chamber. The beads are incubated in the cell suspension and
allowed to bind to the cells and all reaction chamber samples are then transferred to a filtration
chamber 30 where each reaction chamber sample is filtered. The resulting filters or filtered
materials are arranged so that all of them are simultaneously transferred to a single glass slide such
as glass slide 32. The resulting slide contains a series of wells, each well corresponding to a
reaction chamber sample. The multi-well slide can be stained, then scanned under a microscope.
Each well can correspond to a mulliparameter analysis, which is performed in minutes. Figure 5 is
a schematic for a suggested lymphoma panel slide using such a procedure. Fig. 5 shows 6 wells,
each having run a 3-bead set as shown for multiparameter analysis. In the upper left hand comer
is "CD20/kappa/lambda". This indicates a well where the machine ran the CD20/kappa/lambda
analysis described earlier herein. The other 5 wells give antibody information for running similar
analyses as known in the art. Optionally a fourth or fifth set of beads can be added for further
levels of analysis. Preferably after the single parameter or multiparameter incubation and filtration
is carried out, the resulting complexes (such as in Fig. 3) are stained by immunohistochemistry or
in-situ hybridization and then evaluated. Coated glass slides are preferred, to increase
adhesiveness. Preferably, the slides are stained, coverslipped and examined by routine light
microscopy to assess binding. Cells bound to beads are preferably assessed to characterize and
ensure cell type.
In the present invention ceils in suspension in fixative or tissue media can be phenotyped
by antibody coaled beads and isolated from the surrounding milieu by the use of a filter of proper
pore size. These bound cells, thus separated from the sea of other cells, can be transferred to a
glass slide and stained with a variety of stains for visualization. In addition, if imrounopbenotyping
is not desired, a routine cytologic preparation using a variety of methods such as cytospin, cell
block, or ThinPrep can be prepared.
Single parameter analysis can be used to phenotype cells of interest, such as enumerating
relative numbers of kappa and lambda-bearing B lymphocytes. Another application is the isolation
of MN/CA9 positive cervical epithelial cells.
Certain cell surface markers can be semi-quantitated by first isolating cells of interest and
then enumerating the average number of beads bound to the surface.
It should be evident that this disclosure is by way of example and that various changes
may be made by adding, modifying or eliminating details without departing from the fair scope of
the teaching contained in this disclosure. The invention is therefore not limited to particular details
of this disclosure except to the extent that the following claims are necessarily so limited.
WHAT IS CLAIMED IS:
1. A method of characterizing cells comprising the steps of:
a) providing suspension of cells in a liquid medium, said cells including first cells,
b) contacting a group of first beads with said suspension, each of said first beads being coated with a
binding substance or being magnetic such that each first bead is adapted to bind to at least one of said first cells,
c) incubating said first beads with said suspension for a period of time effective to permit said first cells
to bind to said first beads to form first bead-first cell complexes, each first bead-first cell complex comprising a
first bead and a first cell,
d) separating said first bead-first cell complexes from said suspension by filtration through a filter, and
e) examining said separated first bead-first cell complexes and characterizing said first cells
2. A method according to claim 1, further comprising the steps of:
a) prior to contacting the first beads with the suspension, permeabilizing said first cells and incubating
said first cells with paramagnetic microspheres which are bound to a reactive biomarker such that said reactive
biomarker binds to said first cell or inside said first cell, and wherein each first bead is magnetic.
3. A method according to claim 2, wherein each paramagnetic microsphere is less than 1 micron in
diameter and each first bead is more than 3 microns in diameter.
4. A method according to claim 2, wherein said reactive biomarker is selected from the group
consisting of antimyeloperoxidase antibodies, anti-terminal deoxytidyl transferase antibodies, specific UNA
probes, and specific DNA probes.
5. A method according to claim 1, wherein said suspension of cells includes second cells, said second
cells and said first cells being in groups which do'not overlap, said method including simultaneous single
parameter analysis and further comprising the steps of:
1) prior to said filtration step, adding to said suspension a group of second beads, each of said second
beads being coated with a binding substance or being magnetic such that each second bead is adapted to bind to
a second cell,
2) incubating said second beads with said suspension for a period of time effective to permit said
second beads to bind to said second ceils to form second bead-second cell complexes, and
3) simultaneously separating said second bead-second cell complexes and said first bead-first cell
complexes from said suspension by filtration.
6. A method according to claim 1, wherein said suspension of cells includes second cells which are a
subset of said first cells, said method including multiparameter analysis and further comprising the steps of:
1) prior to said filtration step, adding to a suspension comprising said first beads and first cells a group
of second beads, each of said second beads being coated with a binding substance or being magnetic such that
each second bead is adapted to bind to a second cell,
2) incubating said second beads with said suspension for a period of time effective to permit said
second beads to bind to said second cells to form first bead-second cell-second bead complexes, each first bead-
second cell-second bead complex comprising a first bead, a second cell, and a second bead, and
3) separating said first bead-second cell-second bead complexes from said suspension by filtration.
7. A method according to claim 6, wherein third cells are a subset of said first cells, and wherein said
third cells are a subset of said second cells or are different from said second cells, said method further
comprising the steps of:
1) adding to (a) a suspension containng said first beads, said first cells, said second cells and said
second beads or (b) a suspension containing said first beads and said first cells but not said second beads, a
group of third beads, each of said third beads being coated with a binding substance or being magnetic such that
each third bead is adapted to bind to a third cell,
2) incubating said third beads in the suspension to which they have been added for a period of time
effective to permit said third beads to bind to said third cells to form first bead-third cell-third bead complexes,
each first bead-third cell-third bead complex comprising a first bead, a third cell and a third bead, and
3) filtering said suspension to which said third beads were added to separate bead-cell complexes which
have formed.
8. A method according to claim 6, wherein said first beads and said second beads are visually
distinguishable in size or color.
9. A method according to claim 7, wherein said second beads and said third beads are visually
distinguishable in size or color.
10. A method according to claim 7, wherein said second beads are coated with anti-kappa antibody and
said third beads are coated with anti-lambda antibody.
11. A method according to claim 5, wherein said first beads and said second beads are visually
distinguishable in size or color.
12. A method according to claim 1, further comprising the step of transferring to a glass slide the bead-
cell complexes separated by said filtration.
13. A method according to claim 12, further comprising the step of staining the cells in the bead-cell
complexes to assist in their visualization or characterization.
14. A method according to claim 1, wherein said binding substance is selected from the group
consisting of antibodies to specific cell surface proteins, small molecules that bind receptors or other cell surface
molecules, avidin and biotin.
15. A method according to claim 1, wherein said binding substance includes an antibody.
16. A method according to claim 1, wherein said filtration is accomplished using a filter having a pore
size effective to permit substantial amounts of unbound beads to pass through but to trap substantial amounts of
bound beads.
17. A method according to claim 1, wherein said first beads have a diameter of at least 3 microns.
18. A method according to claim 1, wherein said first beads are polystyrene microspheres having a
diameter of 5-20 microns.
19. A method according to claim 1, further comprising the steps of trapping said complexes on a filter
by said filtration, quantitating the number of beads on said filter, and estimating the average number of cells
bound to each bead.
20. A method according to claim 19, wherein the number of beads on the filter is quantitated using a
method selected from the group consisting of light scattering, reflectance, fluorescence, and electrostatic field
changes.
21. A method according to claim 1, further comprising the step of amplifying the signal of a weakly
expressed antigen on the surface of said first cells to facilitate the binding of said first beads.
22. A method according to claim 1, wherein the formation of said first bead-first cell complexes is
effective to isolate a target cell population, said method further comprising the step of detecting a second
parameter using a conventional immunohistochemical technique.
23. A method of characterizing cells comprising the steps of:
a) providing a suspension of cells in a liquid medium,
b) adding to said suspension a group of coated first beads, each of said first beads being coated with a
binding substance such that each first bead is adapted to bind to a preselected type of cell,
c) incubating said group of first beads in said suspension for a period of time effective to permit said
first beads to bind to said preselected type of cell to form bead-cell complexes,
d) filtering said suspension to trap on a filter any bead-cell complexes which have formed, and
e) examining the results of the filtration step in order to characterize cells in said suspension.
24. A method according to claim 23, further comprising the step of prior to said filtration step, adding
to said suspension a group of substantially identical coated second beads different from said first beads, each of
said second beads being coated with a binding substance such that each second bead is adapted to bind to a
normal cell, said preselected type of cell being a normal cell.
25. A method according to claim 24, said steps being adapted to characterize dysplastic cells of a
myelodysplastic disorder.
26. A kit comprising at least one group of substantially identical first beads, each of said first beads
being coated with a binding substance or being magnetic such mat each first bead is adapted to bind to a first
cell, said kit further comprising a set of instructions effective to instruct a technician in how to use said first
beads to perform single parameter or multiparameter analysis on a suspension containing first cells, said
instructions including a step of separating first bead-first cell complexes from said suspension by filtration
through a filter.
27. A kit according to claim 26, further comprising a filter adapted to trap said first bead when said
fijst bead is complexed with said first cell.
28. An apparatus for performing single parameter or multiparameter analysis on a suspension of cells,
said apparatus comprising a sample loader, a plurality of reaction chambers, and a filtration chamber.
29. A method according to claim 1, wherein step (e) includes visually examining said separated first
bead-first cell complexes and visually characterizing said first cells.
A method of characterizing cells comprising the steps of: providing a
suspension of cells in a liquid medium, said cells including first cells,
contacting a group of first beads with said suspension, each of said first
beads being coated with a binding substance or being magnetic such that
each first bead is adapted to bind to at least one of said first cells, incubating
said first bead with said suspension for a period of time effective to permit
said first cells to bind to said first beads to form first bead-first cell
complexes, each first bead-first cell complex comprising a first bead and a
first cell, separating said first bead-first cell complexes from said suspension
by filtration through a filter, and examining said separated first bead-first
cell complexes and characterizing said first cells.

Documents:


Patent Number 225453
Indian Patent Application Number IN/PCT/2001/01147/KOL
PG Journal Number 46/2008
Publication Date 14-Nov-2008
Grant Date 12-Nov-2008
Date of Filing 02-Nov-2001
Name of Patentee PANKOWSKY, DAN A
Applicant Address 6030 BRESSLYN ROAD, NASHVILLE, TN
Inventors:
# Inventor's Name Inventor's Address
1 PANKOWSKY, DAN A 6030 BRESSLYN ROAD, NASHVILLE, TN 37205
PCT International Classification Number G01N 33/48, 33/53
PCT International Application Number PCT/US2000/12127
PCT International Filing date 2000-05-03
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 60/132,395 1999-05-04 U.S.A.