Title of Invention

MONOCLONAL ANTIBODY REACTIVE TO HUMAN CHOLESTROL ESTER TRANSFER PROTEIN.

Abstract MONOCLONAL ANTIBODIES WHICH HAS BINDING SPECIFICITY TO THE HUMAN CETP (CETP INHIBITION ACTIVITY) AVAILABLE AS REAGENTS FOR THE HUMAN CETP PURIFICATION OR DETERMINATION, AND PHARMACEUTICALS OF PREVENTION AND/OR TREATMENT FOR HYPERLIPIDEMIA OR ARTERIOSCLEROSIS ARE PROVIDED. FURTHERMORE, THE PURIFICATION OF THE DETERMINATION METHODS OF THE HUMAN CETP BY USING THE MONOCLONAL ANTIBODY IS ALSO PROVIDED.
Full Text FIELD OF THE INVENTION
The present invention relates to hybridoma producing
monoclonal antibody reactive to human cholesterol ester
transfer protein(CETP), monoclonal antibody and its fragment
reactive to human CETP, immobilized monoclonal antibody and
immobilized antibody fragment, labeled monoclonal antibody and
labeled antibody fragment, a kit for detection, assay,
separation or purification of human CETP, a method for
detection, assay, separation and purification of human CETP
and a pharmaceutical composition containing said monoclonal
antibody or said antibody fragment. This application is divided
out of Indian application no.782/Cal/96.
BACKGROUND OF THE INVENTION
There are three types of cholesterol, free type, long
chain fatty acid type and ester type, in all the tissues and
blood plasma in organisms. The former two play important role
in consisting of cell membrane. The latter is physiologically
inactive and is mainly existing as a storage form. The
cholesterols are derived from ingestion at small intestine or
from biosynthesis at various tissues, especially at liver.
Most of the cholesterols are derived from biosynthesis at
liver.
Free cholesterol biosynthesized and secreted from liver
is incorporated in very low density lipoprotein(VLDL). Then,
by the actions of lipoprotein lipase(LPL) and hepatic
triglyceride lipase(HTGL), it is metabolized to low density
1A
lipoprotein (LDL) through intermediate density lipoprotein
(IDL). By incorporation of LDL into peripheral cells through
LDL receptor, free cholesterol is supplied to cells.
There is a pathway from peripheral cells to liver called
cholesterol reverse transfer system which is reverse direction
of the way from liver to peripheral cells as mentioned above.
Surplus free cholesterol supplied in peripheral cells from
liver is drawn by high density lipoprotein (HDL) in blood.
Then, by the action of lecithin cholesterol acyl
transferase (LCAT), it is converted to cholesterol ester and is
stored in high density lipoprotein (HDL) in blood. By the
action of cholesterol ester transfer protein(CETP), the
cholesterol ester stored in HDL is transferred to VLDL, IDL or
LDL in blood. By incorporation of VLDL, IDL or LDL having
cholesterol ester into liver through LDL receptor, cholesterol
is indirectly transferred to liver.
Recently, the reverse cholesterol transfer system draws
much attention as a mechanism to prevent atherosclerosis by
preventing peripheral cells from accumulation of cholesterol.
In fact, as for HDL which plays important role in the reverse
cholesterol transfer system, many epidemiological surveys show
that decrease of cholesterol ester in blood HDL is one of the
risk factors of coronary artery disorders. It is now well
recognized that HDL is a lipoprotein having anti
atherosclerosis action.
In addition to the importance of blood HDL, it becomes
recognized that CETP is also important because it mediates
transfer of cholesterol ester in HDL into blood LDL.
Therefore, it becomes an urgent matter to elucidate
relationship between CETP and various diseases such as CETP
deficiency, hyperlipemia, hyperalphalipoproteinemia,
hypercholesterolemia, hypolipemia, atherosclerosis, diabetes
and nephrotic syndrome.
For instance, it is demonstrated experimentally that
several times higher levels of CETP are secreted in blood of
the patients with hyperlipemia compared to that of the healthy
volunteers. On the other hand, CETP, HDL-cholesterol and
atherosclerosis have the following relationship. When low
CETP activity hardly causes atherosclerosis, but with high
level of HDL cholesterol. In contrast, when high CETP
activity causes atherosclerosis and with low level of HDL
cholesterol. Such relationship is experimentally
demonstrated(Current Therapy, vol. 7, 9:36-45(1989)).
In order to elucidate the relationship, assay methods for
CETP in body fluid such as blood plasma from healthy person or
patient having the above various diseases, especially
immunoassays such as radio immunoassay(RIA) by using
monoclonal antibody against CETP(anti-CETP monoclonal
antibody), or enzyme immunoassay(EIA, ELISA) is being
developed together with anti-CETP monoclonal antibody for the
assay methods.
As to EIA(ELISA) assay with the anti-CETP monoclonal
antibody, for examples, Imai et al.(Japanese Unexamined Patent
publication NO.HEI6-169793), Nakano, et al.,(Arteriosclerosis,
vol. 19, 11:951, No. 22, (1991)), Takahama, et
al.(Arteriosclerosis, vol. 20, 10:837, No. 135, (1992)), Sato,
et al.(Arteriosclerosis, vol. 20, 10:836, No. 134, (1992)), H.
Mezdur, et al.(Clinical Chemistry, vol. 40, 4:593-597(1994))
Clark et al.(Journal of Lipid Research, vol. 36,:876(1995))
reported sandwich ELISA method by using two kinds of anti-CETP
monoclonal antibodies or their Fab".
However, these assay methods requires complicated
handling. Before assay, plasma sample has to be heat-treated
at 95-100°C and/or pre-treated with a detergent such as Tween-
20 and Triton X-100. As heat treatment, of plasma sample
causes denaturation of CETP in the sample, the assay result
tells only the amount of denatured CETP. So, it is impossible
to assay intact CETP in plasma sample accurately.
Also, R. Clark et al.(FASEB Journal, vol. 8, 7:A1343 No.
495(1994)), Takahashi et al.(Arteriosclerosis, vol. 20, 10:837
No. 136(1992) and ibid. vol. 21, 3:209 No. 97(1993)), Kanamitu
et al.(ibid. vol. 21, 3:209 No. 98(1993)), Waki et al.(ibid.
vol. 22, 5:441 No. 194(1994)) reported the assay results on
CETP in plasma samples by ELISA, however, they did not
described in detail preparation methods and properties of
anti-CETP antibodies and specific assay procedures.
Regarding RIA assay methods with the anti-CETP monoclonal
antibody, Fukazawa et al.(Study on lipid biochemistry, vol.
34:163-166(1992)), Y. Marcel et al.(J. Clin. Invest., vol.
85:10-17(1990) and Adv. Exp. Med. Biol., vol. 243:225-
230(1988)), Fukazawa et al.(J. Biochem., vol. 111:696-
698(1992)), J.Koizumi et al.(Atherosclerosis, 90:189-
196(1991), M. Brown et al. (Nature, vol. 342:448-451(1989)-) and
V. Dangremont et al.(Clinica Chimica Acta, vol. 231:147-
160(1994)) published reports.
However, these RIA methods also had defects as EIA(ELISA)
methods had. The defects were complexity of handling (the
methods required pre-treatment of plasma sample with a
detergent) and/or insufficient sensitivity for detection.
As described above, many researchers tried to establish
assay method for CETP- However, there is no report that such
a convenient and sensitive system which needs no pretreatment
of a sample and enables to determine conveniently the amount
of intact CETP was established.
To elucidate relationship between the diseases (such as
atherosclerosis, hyperlipemia and hyper high density
lipoproteinemia) and CETP that plays important role in the
cholesterol reverse transfer system which may be highly
related to the onset of the diseases, it is strongly requested
to develop a simple and sensitive assay method that can be
widely applicable to clinical purposes to assay intact CETP in
body fluid including blood plasma from healthy person or any
patient, and to develop monoclonal antibody used for said
assay method. However, they have not been established yet.
The present invention provides an assay method widely
applicable for clinical purposes and the anti-human CETP
monoclonal antibody which is very useful not only for said
assay method but also as a reagent for separation/purification
of CETP and for a pharmaceutical composition.
SUMMARY OF THE INVENTION
The inventors of the present invention investigated ,
thoroughly on assay methods for CETP in human body fluid that
can be widely applicable for clinical purposes and on
monoclonal antibodies against human CETP used for said assay
methods, and, by using biologically active purified human CETP
as an inununogen were succeeded in preparing three anti-human
CETP monoclonal antibodies which respectively has different
high binding specificity(CETP inhibitory activity) to human
CETP, especially intact CETP in human body fluid.
Furthermore, as said three anti-human CETP monoclonal
antibodies have high binding specificity(CETP inhibitory
activity) to human CETP, especially intact CETP in human body
fluid, the inventors found that, for assaying intact CETP in
human body fluid(blood plasma etc.)/ the immunoassay using the
anti-human CETP monoclonal antibodies of the present invention
can provide a simple and sensitive assay method which have
not been established so far, and thus the inventors completed
the present invention.
Particularly, as the three anti-human CETP monoclonal
antibodies have high but different binding specificity(CETP
inhibitory activity) to human CETP(especially to intact CETP
in human body fluid), by using combination of any of the two
of the said three monoclonal antibodies for sandwich ELISA,
the inventors were succeeded in developing simpler and more
sensitive assay method which can be widely applicable for
clinical purposes.
As the anti-human CETP monoclonal antibodies have high
binding specificity(CETP inhibitory activity) to human
CETP(especially to intact CETP in human body fluid), by using
the monoclonal antibodies of the invention, it is possible to
assay human CETP simply and sensitively without any pre-
treatment such as heat treatment or detergent treatment of a
plasma sample.
In addition to that, as the anti-human CETP monoclonal
antibodies of the invention have high CETP inhibitory
activity, they are useful as Pharmaceuticals for treatment or
prevention of various diseases caused by abnormal dynamics
such as atherosclerosis, hyperlipemia, high blood HDL and
hypercholesterolemia.
The first aspect of the present invention is a monoclonal
antibody having at least the following characteristics of:
(a) Reactive to plasma CETP(Cholesterol Ester Transfer
Protein) of healthy human, hyperlipemia patients,
LCAT(Lecithin Cholesterol Acyl Transferase) deficiency
patients or hyper HDL patients.
(b) Not reactive to rabbit CETP at the concentration of 3
µg/ml or below.
(c) Not specially reactive to denatured human CETP.
The second aspect of the present invention is the
hybridomas which produce monoclonal antibodies reactive to
human CETP, more specifically, they are hybridomas #72-1 and
#86-2 identified by the Accession Number FERM BP-4944 and FERM
BP-4945 respectively.
The third aspect of the present invention is the
monoclonal antibodies reactive to human CETP, more
specifically, they are monoclonal antibodies #72-1 and #86-2,
and are derived respectively from the hybridomas #72-1 and
#86-2 identified by the Accession Number FERM BP-4944 and FERM
BP-4945 respectively.
The fourth aspect of the present invention is recombinant
chimeric monoclonal antibody reactive to human CETP comprising
a variable region derived from that of the above mentioned
monoclonal antibody and a constant region derived from that of
human immunoglobulin.
The fifth aspect of the present invention is the
recombinant humanized monoclonal antibody reactive to human
CETP, in which a part of or the whole of the complementarity
determining regions of the hypervariable region are derived
from that of the above mentioned monoclonal antibody, the
framework regions of the hypervariable region are derived from
that of human immunoglobulin, and the constant region is
derived from that of human immunoglobulin.
The sixth aspect of the present invention is the antibody
fragment termed F (ab") 2 or Fab" derived from the above
mentioned monoclonal antibody, the above mentioned recombinant
chimeric monoclonal antibody or the above mentioned
recombinant humanized monoclonal antibody.
The seventh aspect of the present invention is the
immobilized monoclonal antibody and the immobilized antibody
fragment. The immobilized monoclonal antibody is prepared by
immobilizing the monoclonal antibody, the recombinant chimeric
monoclonal antibody or the recombinant humanized monoclonal
antibody on an insoluble carrier. The immobilized antibody
fragment is prepared by immobilizing the above mentioned
antibody fragment F(ab")2 or Fab" on an insoluble carrier.
More specifically, the immobilized monoclonal antibody or
the immobilized antibody fragment immobilized on a plate, test
tube, tube, beads, ball, filter, membrane or insoluble carrier
used for affinity column chromatography.
The eighth aspect of the present invention is the labeled
monoclonal antibody and the labeled antibody fragment. The
labeled monoclonal antibody is prepared by labeling the
monoclonal antibody, the recombinant chimeric monoclonal
antibody or the recombinant humanized monoclonal antibody with
a substance capable of providing detectable signal
independently or by reaction with other substance. The
labeled antibody fragment is prepared by labeling the F(ab")2
or Fab" with a substance capable of providing detectable
signal independently or by reaction with other substance.
More specifically, they are the labeled monoclonal
antibody or the labeled antibody fragment labeled with an
enzyme, a fluorescent material, a chemical luminous material,
biotin, avidin or radioisotopes.
The ninth aspect of the present invention is a kit for
assay or detection of human CETP comprising at least the
monoclonal antibody, the recombinant. chimeric monoclonal
antibody or recombinant humanized monoclonal antibody, the
above mentioned antibody fragment F(ab")2 or Fab", the
immobilized monoclonal antibody or immobilized antibody
fragment, or the labeled monoclonal antibody or the labeled
antibody fragment.
Specifically, a kit for assay or detection of human CETP
containing the immobilized monoclonal antibody or the
immobilized antibody fragment and the labeled monoclonal
antibody or the labeled antibody fragment.
The tenth aspect of the present invention is a method for
assay and detection of human CETP by immunoassay characterized
by using at least of the monoclonal antibody, the recombinant
chimeric monoclonal antibody or the recombinant humanized
monoclonal antibody, the antibody fragment F(ab")2 or Fab",
the immobilized monoclonal antibody or the immobilized
antibody fragment, or the labeled monoclonal antibody or the
labeled antibody fragment.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Fig. 1 shows the chromatogram of Phenyl Sepharose
column chromatography of human CETP.
Fig. 2 shows the chromatogram of Resource Q column
chromatography of human CETP.
Fig. 3 shows the chromatogram of Affinity column
chromatography by using the monoclonal antibody #72-1 of
human CETP.
Fig. 4 shows the molecular weight of human CETP
purified the affinity column chromatography by using the
oclonal antibody #72-1.
Fig. 5 shows the reactivity of the monoclonal
antibodies, #72-1, #86-2, and #176-1 for the purified human
CETP.
Fig. 6 shows the chromatogram by Phenyl Sepharose
column chromatography of rabbit CETP.
Fig. 7 shows the chromatogram by Blue Sepharose column
chromatography of rabbit CETP.
Fig. 8 shows the chromatogram by the succinylated LDL
column chromatography of rabbit CETP.
Fig. 9 shows the reactivity of the monoclonal
antibodies, #72-1, #86-2, and #176-1 for the purified
rabbit CETP.

Fig. 10 shows the sensitivity of the determination
when the labeled monoclonal antibody #86-2 and several
immobilized antibodies are combined.
Fig. 11 shows the sensitivity of the determination
when the labeled monoclonal antibody #176-1 and several
immobilized antibodies are combined.
Fig. 12 shows the sensitivity of the determination
when the labeled monoclonal antibody #72-1 and several
immobilized antibodies are combined.
Fig. 13 shows the sensitivity of the determination
when the labeled monoclonal antibody #86-2 and several
concentration of the immobilized antibody #72-1 are
combined.
Fig. 14 shows the sensitivity of the determination
when the labeled monoclonal antibody #72-1 and several
concentration of the immobilized antibody #86-2 are
combined.
Fig. 15 shows the sensitivity of the determination
when the labeled monoclonal antibody #176-1 and several
concentration of the immobilized antibody #72-1 are
combined.
Fig. 16 shows the sensitivity of the determination
when the labeled monoclonal antibody #72-1 and several
concentration of the immobilized antibody #176-1 are
combined.
Fig. 17 shows the sensitivity of the determination
when the labeled monoclonal antibody #72-1(1 µg/ml) and the
immobilized antibody #86-2(1 ng/well or 3 ng/well) are
combined.

Fig. 18 shows a calibration curve of the purified
human CETP standard preparations obtained from the
determination method of the present invention.
Fig. 19 shows a calibration curve of the human CETP
standard preparations from human plasma with different
purity obtained from the determination method of the
present invention.
Fig. 20 shows a correlation between the amount
determined and the activity of CETP in the samples by
using the determination method of the present invention.
Fig. 21 shows the amount determined and the activity
of plasma CETP from normal subjects or various patients by
using the determination method of the present invention.
Fig. 22 shows the reactivity of the monoclonal
antibodies, #72-1 or #86-2 for the denatured human CETP,
and the difference of the determination method between the
present invention and conventional one.
Fig. 23 shows the CETP inhibition effect of anti-CETP
monoclonal antibody in vivo test of rabbit.
Fig. 24 shows the CETP inhibition effect of anti-human
CETP monoclonal antibody in vivo test of transgenic mice
which highly express human CETP.
Fig. 25 shows the effect to the HDL choresterol level
in plasma from anti-human CETP antibody in vivo test.
DETAIL DESCRIPTION OF THE INVENTION
The first specific aspect is a method for assay or
detection of human CETP by immunoassay comprising at least the
following steps of:

(a)reacting a sample with the above mentioned immobilized
monoclonal antibody or the immobilized antibody fragment; and
(b)reacting the labeled monoclonal antibody or the
labelOed antibody fragment with antigen-antibody complex. The
antigen-antibody complex formed by binding human CETP in a
sample with said immobilized monoclonal antibody or said
immobilized antibody fragment.
The second specific aspect is a method for assay or
detection of human CETP by immunoassay comprising at least the
following steps of:
(a) reacting a sample with the above mentioned labeled
monoclonal antibody or the labeled antibody fragment; and
(fc>) reacting the above mentioned immobilized monoclonal
antibody or the immobilized antibody fragment with antigen-
antibody complex. The antigen-antibody complex formed by
binding human CETP in a sample with said labeled monoclonal
antibody or said labeled antibody fragment.
The third specific aspect is a method for assay or
detection of human CETP by immunoassay comprising at least the
following step of:
(a) reacting a mixture comprising the immobilized
monoclonal antibody or the immobilized antibody fragment, the
labeled monoclonal antibody or the labeled antibody fragment
and a sample.
The fourth specific aspect is a method for assay or
detection of human CETP by immunoassay comprising at least the
following step of:
(a) reacting a sample and the labeled human CETP standard
labeled with a labeling substance capable of providing

detectable signal independently or by reaction with other
substance with the above mentioned immobilized monoclonal
antibody or the immobilized antibody fragment.
The fifth specific aspect is a method for assay or
detection of human CETP by immunoassay comprising at least the
following step of (a) or following steps of (b) and (c):
(a) reacting the above mentioned monoclonal antibody or
antibody fragment with a mixture of a sample and the labeled
human CETP standard. The labeled human CETP standard is
prepared by labeling with a substance capable of providing
detectable signal independently or by reaction with other
substance;
(b) reacting the above mentioned monoclonal antibody or
the antibody fragment with a sample;
(c) followed by the step (b), reacting the labeled human
CETP standard with the reaction mixture of step (b). The
labeled human CETP standard is prepared by labeled with a
substance capable of providing detectable signal independently
or by reaction with other substance.
More specifically, a method for assay or detection of
human CETP by immunoassay comprising at least the following
steps of (a) and (d), or steps of (b) to (d):
(a) reacting the monoclonal antibody or the antibody
fragment of the present invention with a mixture of a sample
and the labeled human CETP standard. The labeled human CETP
standard is prepared by labeling with a substance capable of
providing detectable signal independently or by reaction with
other substance;

(b) reacting the monoclonal antibody or the antibody
fragment of the present invention with a sample;
(c) followed by the step (b), reacting the labeled human
CETP standard with the reaction mixture of step (b). The
labeled human CETP standard is prepared by labeling with a
substance capable of providing detectable signal independently
or by reaction with other substance;
(d) reacting an anti-serum derived from mammals reactive
to said monoclonal antibody or said antibody fragment with an
antigen-antibody complex. The antigen-antibody complex is
formed by binding human CETP in said sample or said labeled
human CETP standard with said monoclonal antibody or said
antibody fragment.
The eleventh aspect of the present invention is a kit for
separation or purification of human CETP comprising the
immobilized monoclonal antibody or the immobilized antibody
fragment.
The twelfth aspect of the present invention is a method
for separation or purification of human CETP by affinity
chromatography by using the immobilized monoclonal antibody or
the immobilized antibody fragment. More specifically, a
purification method for human CETP by using column
chromatography.
The thirteenth aspect of the present invention is a mouse
introduced DNA encoding a human CETP which constantly secretes
human CETP in blood without extrinsic or artificial induction.
The fourteenth aspect of the present invention is a
pharmaceutical composition comprising any one of the
monoclonal antibody, the recombinant chimeric monoclonal

antibody, the recombinant humanized monoclonal antibody or the
antibody fragment (F(ab")2 or Fab"), and a pharmaceutically
acceptable carrier. More specifically, the pharmaceutical
composition for treating and/or preventing hyperlipemia or
atherosclerosis.
By clarifying the meanings of the terms used here, the
present invention is explained in detail.
"A monoclonal antibody" of the present invention means a
monoclonal antibody reactive to human CETP and more
specifically, monoclonal antibody having at least the
following characteristics (a), (b) and (c).
(a) Reactive to plasma CETP (Cholesterol Ester Transfer
Protein) of healthy human, hyperlipemia patients,
LCAT(Lecithin Cholesterol Acyl Transferase) deficiency
patients or hyper HDL(high density lipoprotein) patients.
(b) Not reactive to rabbit CETP at the concentration of 3
µg/ml or below.
(c) Not specifically reactive to denatured human CETP.
In addition, the monoclonal antibody of the present
invention has a characteristic that it is reactive to intact
CETP in human body fluid.
"Denatured human CETP" mentioned here means human CETP of
which higher-order structure(conformation) of protein has
destroyed due to such as heat treatment or treatment with
detergent(Tween-20, Triton X-100 etc.), or which is
biologically inactive.
More specifically, "monoclonal antibody" means the
monoclonal antibodies #72-1 and #86-2 derived from the
hybridomas #72-1 and #86-2 identified by Accession Number FERM

BP-4944 and FERM BP-4945 respectively, and the monoclonal
antibody #176-1 produced from the hybridoma #17 6-1 prepared in
the example described below.
Furthermore, it includes a recombinant chimeric
monoclonal antibody, a recombinant humanized monoclonal
antibody which can be prepared by genetic recombination,
derived from said monoclonal antibody, and also includes human
monoclonal antibody.
The monoclonal antibodies of the present invention(for
example, #72-1, #86-2 and #176-1) can be prepared by
conventional preparation methods established for monoclonal
antibodies. For instance, they can be produced from
hybridomas prepared by cell fusion. That is, by immunizing
mammals with antigen, antibody producing cells can be
obtained. Hybridoma cells are prepared with said antibody
producing cells and myeloma cells which does not have ability
to produce autoantibody. After cloning of said hybridoma, a
clone which produces monoclonal antibody showing specific
affinity to the antigen used for immunization of the mammals
is selected and then, the monoclonal antibody of the present
invention is produced from the hybridoma.
Specifically, non-denatured, intact, and biologically
active purified human CETP is used as an antigen. Mammal
(including transgenic animals such as genetically engineered
mouse which produces human antibody), more specifically,
mouse, rat, hamster or guinea pig, is immunized with said
antigen by injecting said antigen once to several times
subcuteneously, intramuscularly, intravenously, into food pad
or intraperitoneally.

In general, immunization is performed once to four times
every one to fourteen days from the initial immunization.
Antibody producing cells are obtained from said immunized
mammal approximately one to five days after the final
immunization.
The hybridoma which secretes monoclonal antibody can be
prepared according to the method by Kohler, and Milstein et
al.(Nature, vol. 256:495-497(1975)) or according to modified
method similar to the original method. Hybridoma is prepared
by cell fusion of antibody producing cells and myeloma cells.
The antibody producing cells are contained in spleen, lymph
node, bone marrow or tonsil, preferably in spleen, which is
obtained from the mammals immunized according to the above
mentioned procedures. The myeloma cells incapable of
producing autoantibody are derived from mammals preferably
from mouse, rat, guinea pig, hamster, rabbit or human, more
preferably from mouse, rat or human.
As myeloma cells to be used for cell fusion, for example,
mouse derived myeloma P3/X63-AG8..653(653), P3/NSl/l-Ag4-l(NS-
1), P3/X63-Ag8.Ul(P3Ul), SP2/O-Agl4(Sp2/O, Sp2), PAI, FO or
BW5147, rat derived myeloma 210RCY3-Ag.2.3., human derived
myeloma U-266AR1, GM1500-6TG-A1-2, UC729-6, CEM-AGR, D1R11 or
CEM-T15 and so forth can be used.
Screening of hybridoma can be performed by culturing the
hybridoma on microtiter plate as an example, then, by
measuring reactivity of the culture supernatant of the well
which shows proliferation to purified human CETP used for the
immunization of mammals by ria or by enzyme immunoassay such
as ELISA.

Preparation of monoclonal antibody from hybridoma is
performed by culturing the hybridoma in vitro or by placing
the hybridoma in vivo in ascites of mouse, rat, guinea pig,
hamster or rabbit, preferably in ascites of mouse or rat, more
preferably in ascites of mouse, and then, by isolating
monoclonal antibody from the culture supernatant or from the
ascites of mammals.
In case of culturing hybridoma in vitro, depending on the
characteristics of cells, purpose of study, culturing method
and so forth, known nutrient media or any kind of nutrient
media modified from known basic media can be used as long as
the media is usable to proliferate, maintain and keep the
hybridoma and to produce monoclonal antibody in culture
supernatant.
As a basic media, for example, low calcium media such as
Ham"Fl2 media, MCDB153 media and low calcium MEM media and
high calcium media such as MCDB104 media, MEM media, D-MEM
media, RPMI1640 media, ASF104 media or RD media can be
applied. Depending on purpose of culture, said basic media
may contain, for example, serum, hormones, cytokines and/or
various inorganic or organic substances.
Isolation and purification of the monoclonal antibody
from the above mentioned culture supernatant or ascites can be
performed by applying to saturated ammonium sulfate
precipitation, euglobulin precipitation, caproic acid method,
caprylic acid method, ion exchange chromatography(DEAE, DE52
or the like), affinity column chromatography such as anti-
immunoglobulin column chromatography and protein A column
chromatography, and so forth.

"Recombinant chimeric monoclonal antibody" of the present
invention means genetically engineered monoclonal antibody,
specifically chimeric monoclonal antibody such as recombinant
mouse/human chimeric monoclonal antibody characterized by its
variable region derived from that of the above mentioned
monoclonal antibody such as the monoclonal antibody #72-1,
#86-2 or #176-1 and its constant region derived from that of
human immunoglobulin. The constant regions derived from human
immunoglobulins have different proper amino acid sequences
based on their isotype such as IgG, IgM, IgA, IgD and IgE.
The constant region of human immunoglobulin of any isotype can
be applicable to the constant region of the recombinant
chimeric monoclonal antibody of the present invention. The
constant region of IgG is preferable.
Recombinant mouse/human chimeric monoclonal antibody
derived from the monoclonal antibody #72-1, #86-2 or #176-1
included in the monoclonal antibodies of the present invention
can be prepared as follows, however, it is not limited to the
following preparation method.
The recombinant chimeric monoclonal antibody can be
prepared by, for example, referring Experimental
Medicine (special edition) vol. 1-6, No. 10, 1988 and Japanese
patent publication No. HEI 3-73280. At the downstream of the
active VH gene(rearranged VDJ gene encoding variable region of
H chain), the CH gene(C gene encoding constant region of H
chain) is operably linked to, and at the downstream of the
active VL gene(rearranged VJ gene encoding variable region of
L chain), the CL gene(C gene encoding constant region of L
chain) is operably linked to. These genes are inserted in

same or different expression vector. The vh gene used here is
obtained from DNA encoding the monoclonal antibody #72-1, #86-
2 or #176-1 isolated from the hybridoma #72-1, #86-2 or #176-1
of the present invention. The CH gene and the CL gene are
obtained from DNA encoding human immunoglobulin. The VL gene
is obtained from DNA encoding the monoclonal antibody #72-1,
#86-2 or #176-1 isolated from the hybridoma #72-1, #86-2 or
#176-1 of the present invention. Host cells are transformed
with said vector(s). The recombinant mouse/human chimeric
monoclonal antibody of the present invention can be prepared
by culturing said transformed cells. As a host cell,
prokaryotic cells (e.g. E. coli) or eukaryotic cells (e.g. CHO
cell) can be used.
Briefly, after DNA is extracted from the hybridomas #72-
1, #86-2 or #176-1 by a conventional method, said DNA is
digested with an appropriate restriction enzyme such as EcoRI
and ffindlll. Then, southern blotting is performed by electro-
phoresis (for example, with 0.7% agarose gel). After the
electrophoresis, the gel is stained(for example, with etidium
bromide). After taking photograph of the gel, location of
marker is marked and the gel is washed twice, then, the gel is
immersed in 0.25 M HC1 solution for 15 minutes. Then the gel
is immersed in 0.4 N NaOH for 10 minutes with gentle shaking.
By a conventional method, the gel is transferred on a filter
and after 4 hours standing, the filter is recovered and is
washed twice with 2 x SSC. After drying the filter
completely, baking filter is performed at 75°C for 3 hours.
After the baking, said filter is put in 0.1 x SSC/0.1 % SDS
solution and is treated for 30 minutes at 65°C. The filter is

immersed in 3 x SSC/0.1 % SDS solution. Then, the filter is
put in a vinyl bag with the pre-hybridization solution and
stand for 3 to 4 hours at 65°C.
Then, 32p labeled probe DNA and the hybridization
solution are added, and the mixture is reacted for
approximately 12 hours at 65°C. After hybridization, the
filter is washed at appropriate salt concentration, reaction
temperature and time period(as an example, with 2 x SSC-0.1 %
SDS solution, at room temperature for 10 minutes). Said
filter is then put in a vinyl bag and small amount of 2 x SSC
is added, the bag is closed tightly and autoradiography is
performed.
By the above-mentioned southern blotting, the rearranged
VDJ gene and VJ gene which respectively encode H chain and L
chain of the monoclonal antibody #72-1, #86-2 or #176-1 are
identified. The region including the identified DNA fragment
is fractionated by sucrose density gradient centrifugation and
incorporated into phage vector(such as Charon 4A, Charon 28,
X.EMBL3 and XEMBL4). By transforming E. coli(such as LE392 and
NM539) with said phage vector, genome library is established.
By plaque hybridization with an appropriate probe(such as H
chain J gene and L chain(k) J gene) according to Benton-Davis
method(Science, vol. 196, p.180-182, 1977), positive clones
containing rearranged VDJ gene or VJ gene respectively are
obtained from the genome library. On the obtained clones, the
restriction enzyme map is made, the nucleotide sequence is
determined and existence of the rearranged VH(VDJ) gene or
VL(VJ) gene is confirmed.

On the other hand, human CH gene and human CL gene used
for chimerization are isolated separately. For instance, to
prepare chimeric antibody with human IgGl, C?l gene(CH gene)
and Ck gene(CL gene) are isolated. These genes can be
isolated from human genome library by using mouse C?l
gene(corresponds to human C?l gene) and mouse Ck
gene(corresponds to human Ck gene) as probes because the
nucleotide sequences of mouse immunoglobulin gene and human
immunoglobulin gene are highly homologous.
Briefly, as an example, a DNA fragment containing human
Ck gene and the enhancer region can be isolated from HaeIII-
Alul genome library of the XCharon 4A (Cell, vol. 15:1157-
1174(1978)) by using HindIII-BamHI fragment(3 kb) obtained
from the clone Igl46(Proc. Natl. Acad. Sci. USA, vol. 75:4709-
4713(1978) and EcoRI fragment(6.8 kb) obtained from the clone
MEPlO(Proc. Natl. Acad. Sci. USA, vol. 78:474-478(1981)) as
probes. The human C?l gene can be isolated by, for example,
digesting DNA from human fetal liver cell with Hindlll,
fractionating by agarose gel electrophoresis, inserting 5.9 kb
band into X788 and then isolating with the above mentioned
probes.
Using the isolated a mouse VH gene, mouse VL gene, human
CH gene and human CL gene, and considering the promoter region
and the enhancer region, human CH gene is placed at the
downstream of mouse VH gene and human CL gene is placed at the
downstream of mouse VL gene in a expression vector such as
pSV2gpt and pSV2neo by using an appropriate restriction enzyme
and DNA ligase. In this case, mouse VH gene/human CH gene and

mouse VL gene/human CL gene can be placed in one expression
vector or in different expression vectors.
The expression vector(s) inserted chimeric gene is
introduced in myeloma cells which do not produce antibody such
as P3X63-Ag8-653 cell and SP210 cell by protoplast fusion
method, DEAE-dextran method, calcium phosphate method or
electrical punching method. The transformed cells are
selected by culturing them in culture media containing a drug
which corresponds to the drug resistant gene inserted in the
expression vector(s), and chimeric monoclonal antibody
producing cells can be obtained.
From the culture supernatant of the selected antibody
producing cells, the chimeric monoclonal antibody can be
obtained.
"A recombinant humanized monoclonal antibody" of the
present invention means genetically engineered monoclonal
antibody, specifically means that a part of or the whole of
the complementarity determining regions of hypervariable
region is derived from that of the above mentioned monoclonal
antibody(monoclonal antibody #72-1, #86-2 or #176-1 as
examples), the framework regions hypervariable region are
derived from that of human immunoglobulin, and the constant
region is derived from that of human immunoglobulin.
The complementarity determining region(s) in the
hypervariable region means a part of or the whole of the three
regions(CDR1, CDR2, CDR3) which exist in the hypervariable
region of the variable region of antibody and complementarily
binds directly with antigen. The framework region(s) in super
variable region means the four regions(FR1, FR2, FR3, FR4)

which are located before and after said three complementarity
determining regions, and are relatively well maintained
(constant).
In other words, "Recombinant humanized monoclonal
antibody" means monoclonal antibody in which all of the parts
except for a part of or the whole of the complementarity
determining regions of the hypervariable region of the
monoclonal antibodies of the present invention are replaced
with corresponding region(s) of human immunoglobulin.
The constant region derived from human immunoglobulin has
its proper amino acid sequence depending on its isotype such
as IgG, IgM, IgA, IgD and IgE. The constant region of the
recombinant humanized monoclonal antibody of the present
invention may be the constant region of any isotype of human
immunoglobulin. Preferably, the constant region of human IgG.
And also, the framework region(s) in the hypervariable region
derived from human immunoglobulin is not limited to one
isotype.
The recombinant humanized monoclonal antibody derived
from the monoclonal antibody #72-1, #86-2 or #176-1 included
in the monoclonal antibodies of the present invention can be
prepared by, for example, the following steps but not limited
to the following.
For instance, that can be prepared by genetic engineering
technique according to Japanese Patent Unexamined Publication
Number HEI4-506458 and Japanese Patent Unexamined Publication
Number SYOU62-296890. From the hybridoma #72-1, #86-2 or
#176-1, at least one mouse H chain CDR gene and at least one
mouse L chain CDR gene which corresponds to said mouse H chain

CDR gene are isolated. From human immunoglobulin gene, human
H chain gene which encodes whole region except human H chain
CDR(corresponds to mouse H chain CDR), and human L chain gene
which encodes whole region except human L chain
CDR(corresponds to mouse L chain CDR) are isolated. Said
isolated mouse H chain CDR gene and said H chain gene are
operably linked and are introduced into an appropriate
expression vector, and said mouse L chain CDR gene and said
human L chain gene are operably linked and are introduced into
another appropriate expression vector. Or otherwise, it is
possible to introduce said mouse H chain CDR gene/human H
chain gene and mouse L chain CDR gene/human L chain gene into
the same one expression vector. By transforming host cells
with the obtained expression vector(s), transformed cells
which produce humanized monoclonal antibody can be obtained.
By culturing said transformed cells, human monoclonal antibody
can be obtained from culture supernatant.
As host cells, both prokaryotic cells such as E. coll and
eukaryotic cells such as CHO(Chinese hamster ovarian) cells
may be used.
The term "human antibody" in the present invention means
that the immunoglobulin comprises entire regions including
both constant and variable regions of heavy chains and
those of light chains, and that it is derived from genes
encoding human immunoglobulin.
The human antibody is produced according to the common
method. In general, the human immunoglobulin genes are
incorporated into gene locus of the animals such as mice
except human to obtain transgenic animals producing

humanized antibody. Then, the transgenic animal is
immunized by using any antigen. Thus, polyclonal and/or
monoclonal antibodies are obtained. For instance, such
transgenic mice producing human antibodies are obtained by
using the method disclosed in several references: Nature
Genetics, 7:13-21(1994), NIKKEI Science, June: 40-50(1995),
Nature, 368:856-859(1994), and Japanese National
Publication of translation for the foreign language patent
application No. 1995-500233.
"F(ab")" or "Fab1" of the present invention mean antibody
fragments produced by treating immunoglobulin (monoclonal
antibody) with proteinase such as pepsin and papain. They
mean the antibody fragment(s) digested at the positions before
and after the disulfide bonds between the two H chains in the
hinge region. For example, when IgGl is treated with papain,
it is cleaved at the upstream of the disulfide bond between
the two H chains in the hinge region to make two identical
fragments, i.e., L chain consisting of VL(L chain variable
region) and CL(L chain constant region), and H chain fragment
consisting of VH(H chain variable region) and CH?1(?1 region of
the constant region of H chain) are bound at the C terminal
region by disulfide bond. Each of the two identical
fragments is called Fab". When treated with pepsin, IgGl is
cleaved at the downstream of the disulfide bond between the
two H chains at the hinge region to make one antibody fragment
which is a little larger than a fragment of two Fab" connected
at the hinge region. This antibody fragment is called
F(ab")2-

"Anti serum derived from mammal" of the present invention
means serum containing antibody reactive to the monoclonal
antibody or the its antibody fragment of the present
invention. The serum is prepared by immunizing mouse, rat,
guinea pig, rabbit, goat, pig or cattle, preferably rat,
guinea pig, rabbit or goat, with said monoclonal antibody or
said antibody fragment of the present invention according to
the procedures described above for preparation of the above
mentioned monoclonal antibody. Specifically, antiserum
derived from said mammals immunized with the above mentioned
monoclonal antibody(for example monoclonal antibody #72-1,
#86-2 or #176-1) or antibody fragment F(ab")2 or Fab" of these
antibodies.
"Insoluble carrier" of the present invention means a
carrier which is used in order to carry human CETP in a
sample(for example, body fluid sample such as blood plasma,
culture supernatant or centrifuge supernatant) or the above
mentioned monoclonal antibody or the antibody fragment by, for
example, physical adsorption or chemical bond. As examples,
the following can be used; (1) plastics composed of
polystyrene resin, polycarbonate resin; silicon resin or nylon
resin; plate composed of water insoluble substances such as
glass; test tube or tube having inner capacity; beads, ball,
filter or membrane etc., and (2) insoluble carriers used for
affinity chromatography such as cellulose type carrier,
agarose type carrier, polyacrylami.de type carrier, dextran
type carrier, polystyrene type carrier, polyvinyl alcohol type
carrier, poly amino acid type carrier and porous silica
carrier.

"Immobilized monoclonal antibody" or "immobilized
antibody fragment" of the present invention means the
monoclonal antibody or the antibody fragment which is bound to
said insoluble carrier by physical adsorption or chemical
bond. These immobilized monoclonal antibody or the
immobilized antibody fragment can be used for detection,
assay, separation and purification of human CETP in sample(for
example, body fluid sample such as blood plasma, culture
supernatant and centrifugation supernatant). For the purpose
of said detection or assay, the immobilized monoclonal
antibody or immobilized antibody fragment immobilized on the
insoluble carrier mentioned above (1). Especially for assay,
considering simple handling and simultaneous handling of many
samples, it is preferable to use a plastic plate having many
wells such as microtiter plate with 96 wells. For said
separation and purification, the immobilized monoclonal
antibody or immobilized antibody fragment immobilized on a
filter mentioned above (1) or a membrane mentioned above (2)
can be used.
"Labeling substance capable of providing detectable
signal independently or by reaction with other substance" of
the present invention mean a substance which is used to detect
the above mentioned monoclonal antibody, the antibody fragment
or the human CETP standard. They are detectable by binding
said substance with the antibody, the fragment or the standard
(physicochemical binding etc.), Specifically, the substance
is enzyme, fluorescent material, chemical luminous material,
biotin, avidin or radioisotope, and so forth. More
specifically, the substance is enzyme such as peroxidase,

alkaline phosphatase, ß-D-galactosidase, glucose oxidase,
glucose-6-phosphate dehydrogenase, alcohol dehydrogenase,
malate dehydrogenase, penicillinase, catalase, apo-glucose
oxidase, urease, luciferase and acetylcholine esterase;
fluorescent material such as fluorescence isothiocyanate,
phycobilin protein, rare earth metal chelate, dansylchloride
and tetramethylrhodamin isothiocyanate; radioisotope such as
3H, 14C and 131I. biotin, avidin or chemical luminous
materials.
Radioisotopes and fluorescent materials can provide
detectable signal independently. On the other hand, enzymes,
chemical luminous materials, biotin and avidin can not provide
detectable signal independently, and with one or more other
substance(s), they can provide detectable signal. For
instance, in the case of enzyme, it requires at least its
substrate. Various substrates are used depending on method
for measuring enzyme activity(Colorimetric method,
fluorescence method, bio-luminescence method or chemical
luminescence method etc.). In the case of biotin, generally,
it is reacted with, at least, avidin or enzymatically modified
avidin, but not limited to the method. If it necessary,
various coloring developing substance depending on said
substrates are used.
"Labeled monoclonal antibody", "labeled antibody
fragment" and "labeled human CETP standard" of the present
invention mean the monoclonal antibody, the antibody fragment
and the human CETP standard labeled with said labeling
substance, respectively. These labeled monoclonal antibody,
labeled antibody fragment and labeled human CETP standard can

be used for detection and assay of human CETP in a sample such
as body fluid sample(blood plasma etc.), culture supernatant
and centrifugation supernatant. In the present invention, any
labeling substance mentioned above can be used, however,
considering detection limit(sensitivity), assay limit and
handling(convenience), biotin labeling is preferable.
"Human CETP standard" of the present invention means
human CETP used as a standard for detection or assay of human
CETP in a sample as mentioned above.
"Immunoassay" of the present invention means a method for
detection or assay of an antigen contained in a sample(for
example, body fluid sample such as blood plasma, culture
supernatant and centrifugation supernatant) based on the
principle of antigen-antibody reaction. In the present
invention, any known immunoassay methods can be applicable to
the present invention as long as antibody used for said
antigen-antibody reaction is one or more said monoclonal
antibody or antibody fragment selected from the above
mentioned monoclonal antibody or antibody fragment, the above
mentioned immobilized monoclonal antibody or the immobilized
antibody fragment the above mentioned labeled monoclonal
antibody or the labeled antibody fragment, and as antigen
assayed is human CETP.
Specifically, the methods described in "Enzyme Immuno
Assay"(3rd edition, Eiji Ishikawa et al. ed., Igakusyoin,
1987) such as single antibody solid phase method, double
antibody liquid phase method, double antibody solid phase
method, sandwich method, enzyme multiplied immunoassay
technique(EMIT), enzyme channeling immunoassay, Enzyme

modulator mediated enzyme immunoassay (EMMIA), enzyme
inhibitor immunoassay, immunoenzymometric assay, enzyme
enhanced immunoassay and proximal linkage immunoassay, or one
pot method as described in Japanese Patent Publication No.
HEI2-39747.
In the present invention, depending on purpose of assay,
appropriate immunoassay can be selected. Considering easily
handling and/or economical efficiency, especially considering
wide clinical use, sandwich method, one pot method, single
antibody solid phase method or double antibody liquid phase
method is preferable. It is more preferable to use sandwich
method or one pot method. It is most preferable to use
sandwich method with the immobilized monoclonal antibody or
the immobilized antibody fragment immobilized on a microplate
having many wells such as 96 well microplate and the labeled
monoclonal antibody or the labeled antibody fragment labeled
with enzyme or biotin, or otherwise, one pot method with the
immobilized monoclonal antibody or the immobilized antibody
fragment immobilized on beads or ball and labeled monoclonal
antibody or labeled antibody fragment labeled with enzyme or
biotin.
A specific example of the most preferable embodiment is a
sandwich method or one pot method using the following
combination, the monoclonal antibody #72-1, #86-2 or #176-1,
or their F(ab")2 or Fab1 immobilized on a microplate, beads or
ball and with the monoclonal antibody #72-1, #86-2 or #176-1
or their F(ab")2 or Fab1 labeled with enzyme or biotin.
Although the monoclonal antibodies #72-1, #86-2 and #176-1 can
be used for immobilized form as well as labeled form, it is

preferable to use #72-1 as immobilized form and #86-2 or #176-
1 as labeled form.
Particularly, it is more preferable to use #72-1 (which
is the monoclonal antibody derived from the hybridoma
identified with FERM BP4944) as immobilized monoclonal
antibody and #86-2 (which is the monoclonal antibody derived
from the hybridoma identified with FERM BP4945) as labeled
one.
Details of sandwich method, one pot method, single
antibody solid phase method, double antibody liquid phase
method are described below.
Sandwich method is a method described in the first
specific aspect of the tenth aspect of the present invention,
i.e., an immunoassay comprising at least the following steps
of:
(a) reacting sample with the immobilized monoclonal
antibody or the immobilized antibody fragment of the present
invention; and
(b) reacting the labeled monoclonal antibody or the
labeled antibody fragment with the antigen-antibody complex
formed by binding human CETP in a sample with said immobilized
monoclonal antibody or said immobilized antibody fragment.
Based upon the present invention, most conventional
methods by using enzyme or biotin as labeling substance
specifically described below. Those methods are composed of
such as the following steps but not limited to the following
examples. Each of "immobilized monoclonal antibody" and
"monoclonal antibody immobilized microplate" used below mean
identical material.

(Step 1) a step for preparing an immobilized monoclonal
antibody(monoclonal antibody immobiOOOOlized microplate) by
immobilizing the monoclonal antibody #72-1, #86-2 or #176-1 of
the present invention which is reactive to human CETP on a
microplate;
(Step 2) a step to react a sample with the immobilized
monoclonal antibody by adding a sample such as human blood
plasma to the monoclonal antibody immobilized microplate;
(Step 3) a step to remove non-reacted sample by washing the
monoclonal antibody immobilized microplate;
(Step 4) a step to prepare a labeled monoclonal antibody by
labeling monoclonal antibody #72-1, #86-2 or #176-1 of the
present invention which is reactive to human CETP with an
enzyme such as biotin or peroxidase;
(Step 5) a step to react labeled monoclonal antibody with an
antigen-antibody complex (formed by reacting the immobilized
monoclonal antibody with human CETP in a sample) by applying
labeled monoclonal antibody to the monoclonal antibody
immobilized microplate washed by "Step 3";
(Step 6) a step to remove non-reacted labeled monoclonal
antibody from the antigen-antibody complex and by washing the
monoclonal antibody immobilized microplate;
(Step 7) a step to add avidin or enzyme modified avidin(in
case biotin labeled monoclonal antibody is used at "Step 4"),
or various substrates(in case enzyme labeled monoclonal
antibody such as peroxidase labeled is used at "Step 4",
depending on method used for measuring enzyme activity)
together with a coloring agent(if necessary) to the monoclonal
antibody immobilized microplate (washed at "Step 6) and to

react with labeling substance on the labeled monoclonal
antibody;
(Step 8) a step to react avidin bound enzyme with substrate by
adding various substrates depending on method for measuring
enzyme activity in case enzyme modified avidin is used in
"Step 7";
(Step 9) a step to stop the coloring reaction and enzymatic
reaction by adding stop solution to the monoclonal antibody
immobilized microplate; and
(Step 10) a step to measure intensity of coloring, fluorescent
or luminescence.
Although the monoclonal antibodies #72-1, #86-2 and #176-
1 can be used both as immobilized form and as labeled form,
it is preferable to use #72-1 as immobilized form and #86-2
and #176-1 as labeled form, more preferably #86-2.
One pot method is an immunoassay mentioned in the first,
the second or the third specific aspect of the tenth point of
the present invention. The first is an immunoassay including
at least the following steps of:
(a) reacting sample with the immobilized monoclonal
antibody or the immobilized antibody fragment of the present
invention; and
(b) reacting the labeled monoclonal antibody or the
labeled antibody fragment with antigen-antibody complex formed
by binding human CETP in a sample with said immobilized
monoclonal antibody or said immobilized antibody fragment.
The second is an immunoassay including at least the
following steps of:

(a) reacting a sample with the labeled monoclonal
antibody or the labeled antibody fragment of the resent
invention; and
(b) reacting the immobilized monoclonal antibody or the
immobilized antibody fragment of the present invention with
the antigen-antibody complex formed by binding human CETP in a
sample with said labeled monoclonal antibody or said labeled
antibody fragment.
The third specific aspect is the immunoassay comprising
at least the following step of:
(a) reacting a mixture comprising the immobilized
monoclonal antibody or the immobilized antibody fragment of
the present invention, the labeled monoclonal antibody or
the labeled antibody fragment of the present invention and
a sample.
The above-mentioned three aspect are specifically
explained hereinbelow by using examples. In the example, a
step employs a generally used enzyme as a labeling agent,
and comprises the following steps. However, the present
invention is not limited to such examples given below. The
terms "immobilized monoclonal antibody" and "monoclonal
antibody immobilized beads" mean the same material.
The first step is comprising the following steps.
(Step 1) A step for producing immobilized monoclonal
antibody(monoclonal antibody immobilized beads) by
immobilizing monoclonal antibodies of the present invention
having reactivity to CETP derived from human, #72-1, #86-2,
and #176-1, on the beads respectively;

(Step 2) a step for reacting an analyte in sample solution
with a monoclonal antibody by adding both the monoclonal
antibody immobilized beads and the sample solution such as
human plasma together with buffer solution into a container
having an internal space such as a test tube, plate or
tube;
(Step 3) a step for removing the solution in the container
and washing the monoclonal antibody immobilized beads;
(Step 4) a step for producing labeled monoclonal antibody
by labeling monoclonal antibodies of the present invention,
#72-1, #86-2, or #176-1, which capable of reacting with
human CETP, with enzymes such as biotin or peroxides
(Step 5) a step for reacting the labeled monoclonal
antibody with antigen-antibody complex formed from reaction
between immobilized monoclonal antibody and CETP derived
from human by adding the labeled monoclonal antibody in the
container containing the monoclonal antibody immobilized
beads washed in Step 3;
(Step 6) a step for removing an unreacted labeled
monoclonal antibody which is not reacted with the complex
with the solution in the container by washing the
monoclonal antibody immobilized beads;
(Step 7) a step for reacting a substance attached to the
labeled monoclonal antibody with a substrate by adding
either avidin or enzyme modified avidin when the biotin-
labeled monoclonal antibody is employed in Step 4, or by
adding a substrate suitable for enzyme activity assay
systems employed when the monoclonal antibody labeled by
enzymes such as peroxides is employed in Step 4, if

desirably together with a color developing substance, in
the container containing the monoclonal antibody
immobilized beads washed in Step 6;
(Step 8) a step for reacting an enzyme bound to avidin with
a substrate suitable for the enzyme activity assay systems
employed when the enzyme-modified avidin is added at Step
7;
(Step 9) a step for terminating both enzyme reaction and
color development by adding the terminator solution into
either the reaction system of Step 7 or 8; and
(Step 10) a step for determining the absorption intensity,
fluorescence intensity or luminescence intensity.
The second step is comprising the following steps.
(Step 1) A step for producing labeled monoclonal antibody
by labeling the monoclonal antibodies of the present
invention having reactivity to CETP derived from human,
#72-1, #86-2, and #176-1 with the labeling substance such
as biotin and peroxidase.
(Step 2) a step for reacting sample with labeled monoclonal
antibody by adding both the labeled monoclonal antibody and
the sample solution such as human plasma together with
buffer solution into a container having the internal space
such as the test tube, plate or tube;
(Step 3) a step for producing an immobilized monoclonal
antibody(monoclonal antibody immobilized beads) by
immobilizing the monoclonal antibodies of the present
invention having reactivity to CETP derived from human,
#72-1, #86-2, or #176-1, onto the beads

(-Step 4) a step for reacting the immobilized monoclonal
antibody and the antibody-antigen complex formed from the
labeled monoclonal antibody and the analyte, CETP derived
from human in the sample by adding the monoclonal antibody
immobilized beads in the reaction system of Step 2;
(Step 5) a step for removing the solution in the container
and unreacted labeled monoclonal antibody which is not
reacted with the complex by washing the monoclonal antibody
immobilized beads;
(Step 6) a step for reacting the labeling substance
attached to the labeled monoclonal antibody with the
substrate by adding either avidin or enzyme modified avidin
when the biotin-labeled monoclonal antibody is employed in
Step 1, or by adding the substrate suitable for the enzyme
activity assay systems when the monoclonal antibody labeled
by enzymes such as peroxides*is employed in Step 1, in
desirably together with the color developing substance, in
the container containing the monoclonal antibody
immobilized beads washed in Step 5;
(Step 7) a step for reacting an enzyme bound to avidin with
a substrate suitable for the enzyme activity assay systems
employed added when the enzyme-modified avidin is added at
Step 6;
(Step 8) a step for terminating both enzyme reaction and
color development by adding the terminator solution into
either the reaction system of Step 6 or 7; and
(Step 9) a step for determining the absorption intensity,
fluorescence intensity or luminescence intensity.
The third step is comprising the following steps.

(Step 1) A step for producing immobilized monoclonal
antibody(monoclonal antibody immobilized beads) by
immobilizing the monoclonal antibodies of the present
invention having reactivity to CETP derived from human,
#72-1, #86-2, and #176-1, onto the beads;
(Step 2) a step for producing labeled monoclonal antibody
by labeling the monoclonal antibody having reactivity to
CETP derived from human, #72-1, #86-2, and #176-1, with the
enzyme such as biotin or peroxides;
(Step 3) a step for simultaneous reacting the sample with
both immobilized monoclonal antibody and labeled monoclonal
antibody by adding the sample, both the monoclonal antibody
immobilized beads produced in Step 1, the labeled
monoclonal antibody produced in Step 2, and the sample
solution such as human plasma together with the buffer
solution into the container having the internal space such
as the test tube, plate or tube;
(Step 4) a step for removing the unreacted labeled
monoclonal antibody which is not reacted with the complex
by washing the monoclonal antibody immobilized beads the;
(Step 5) a step for reacting the labeling substance
attached to the labeled monoclonal antibody with the
substrate by adding either avidin or enzyme modified avidin
when the biotin-labeled monoclonal antibody is employed in
Step 2, or by adding the substrate suitable for enzyme
activity assay systems when the monoclonal antibody labeled
with enzymes such as peroxides is employed in Step 2, in
the container containing the monoclonal antibody
immobilized beads washed in Step 4;

(Step 6) a step for reacting an enzyme bound to avidin with
a substrate suitable for the enzyme activity assay systems
employed added when the enzyme-modified avidin is added at
Step 5;
(Step 7) a step for terminating both enzyme reaction and
color development by adding the terminator solution into
either the reaction system of Step 6 or 7; and
(Step 8) a step for determining the absorption intensity,
fluorescence intensity or luminescence intensity.
In the above-mentioned concrete examples, all the
monoclonal antibodies, #72-1, #86-2, and #176-1 may be
employed as both the immobilized and labeled monoclonal
antibodies. However, the monoclonal antibody #72-1 is
preferable as the immobilized monoclonal antibody, and both
the monoclonal antibodies #86-2 and #176-1 are preferable
as the labeled monoclonal antibodies. The monoclonal
antibody #86-2 is more preferable as the labeled one.
A single antibody solid phase method is described
above at the forth of the tenth concrete feature of the
present invention, and it is an immunoassay comprising at
least the following step of:
(a) reacting a sample and a labeled CETP standard labeled
with a labeling substance capable of providing a detectable
signal independently or by reaction with other substances
with the immobilized monoclonal antibody or the immobilized
antibody fragment of the present invention.
According to the present invention, the procedure
which employs the labeling substance, particularly commonly
used enzyme or biotin as the labeling substance, is

explained in detail hereinbelow. For instance, the
procedure comprises the following steps, however, the
present invention is not limited to the example.
Furthermore, the terms of "the immobilized monoclonal
antibody" and "the monoclonal antibody immobilized
microplate" has the same meaning.
(Step 1) A step for producing immobilized monoclonal
antibody(monoclonal antibody immobilized beads) by
immobilizing the monoclonal antibodies of the present
invention having reactivity to CETP derived from human,
#72-1, #86-2, and #176-1, onto the microplate;
(Step 2) a step for producing labeled CETP standard derived
from human by labeling the CETP standard with the enzyme
such as biotin or peroxides;
(Step 3) a step for competitively reacting both the sample
such as human plasma and the CETP standard with immobilized
monoclonal antibody in the monoclonal antibody immobilized
microplate;
(Step 4) a step for removing the unreacted labeled CETP
standard by washing the monoclonal antibody immobilized
microplate;
(Step 5) a step for reacting the labeling substance bound
to CETP standard with a substrate by adding avidin or
enzyme modified avidin as the substrate when the biotin
labeled CETP standard derived from human is employed in
Step 2, or a substrate suitable for enzyme activity assay
systems employed when the enzyme-labeled CETP standard
labeled by enzymes such as peroxides is employed in Step 2,
if desirably together with a color developing substance in

the monoclonal antibody immobilized microplate washed in
Step 4;
(Step 6) a step for reacting the enzyme bound to avidin
with the substrate suitable for the enzyme activity assay
systems when the enzyme-modified avidin is added at Step 5;
(Step 7) a step for terminating both enzyme reaction and
color development by adding the terminator solution into
the monoclonal antibody immobilized microplate; and
(Step 8) a step for determining the absorption intensity,
fluorescence intensity or luminescence intensity.
The monoclonal antibody #72-1, #86-2, and #176-1 may
be used as the immobilized monoclonal antibody, however,
the monoclonal antibody #72-1 is preferable.
A double antibody solid phase method is described
above at the fifth of the tenth concrete feature of the
present invention, and it is an immunoassay comprising at
least the following step of (a) or the following steps of
(b) and (c):
(a) reacting the monoclonal antibody or antibody fragment
with a mixture of a sample and the labeled human CETP
standard. The labeled human CETP standard is prepared by
labeled labeling with a substance capable of providing
detectable signal independently or by reaction with other
substances;
(b) reacting the monoclonal antibody or the antibody
fragment of the present invention with a sample;
(c) followed by the step (b), reacting the labeled human
CETP standard with the reaction mixture of step (b).

More specifically, the present invention is the
immunoassay comprising at least the following steps of (a)
and (d), or steps of (b) to (d).
(a) reacting the monoclonal antibody or the antibody
fragment of the present invention with a mixture of a sample
and the labeled human CETP standard. The labeled human CETP
standard is prepared by labeling with a substance capable of
providing detectable signal independently or by reaction with
other substance;
(b) reacting the monoclonal antibody or the antibody
fragment of the present invention with a sample;
(c) followed by the step (b), reacting the labeled human
CETP standard with the reaction mixture of step (b). The
labeled human CETP standard is prepared by labeling with a
substance capable of providing detectable signal independently
or by reaction with other substance;
(d) reacting an anti-serum derived from mammals
reactive to said monoclonal antibody or said antibody
fragment with an antigen-antibody complex. The antigen-
antibody complex is formed by binding human CETP in said
sample or said labeled human CETP standard with said
monoclonal antibody or said antibody fragment.
According to the present invention, the procedure
which employs the labeling substance, particularly commonly
used enzyme or biotin as the labeling substance is
explained in detail hereinbelow. For instance, the
procedure comprises the following steps, however, the
present invention is not limited to the example.

(Step 1) A step for producing labeled CETP standard derived
from human by labeling the CETP standard with the enzyme
such as biotin or peroxides;
(Step 2) a step for competitively reacting (1) the mixture
comprising both the sample such as human plasma and the
CETP standard derived from human prepared in the above Step
1 to add into the container having internal space such as
the test tube, plate, or tube to react with subsequently
added the monoclonal antibody having the reactivity to the
CETP derived from human of the present invention, #72-1,
#86-2, or #176-1; (2) the sample such as human plasma is
added into the container having internal space such as the
test tube, plate, or tube to react with subsequently added
the monoclonal antibody, #72-1, #86-2, or #176-1, having
the reactivity to the CETP derived from human of the
present invention;
(Step 3) a step reacting the monoclonal antibodies, #72-1,
#86-2, and #176-1, the sample added in Step 2, and the
labeled human CETP standard added later when the labeled
human CETP standard is not added simultaneously;
(Step 4) a step for precipitating as immune-complex
agglutinately by adding animal anti-sera except mice having
the reactivity for mouse monoclonal antibody such as anti-
mouse y globulin goat anti-sera to react the antigen-
antibody complex of the monoclonal antibodies prepared in
Step 2 to 3, #72-1, #86-2, or #176-1, and either human CETP
in the sample or the labeled human CETP standard to form
the complex comprising the antigen-antibody complex and the
animal anti-sera except mice;

(Step 5) a step for removing the agglutinate complex
precipitated by centrifugation of the reaction system in
Step 4;
(Step 6) a step for reacting the immune-complex separated
in Step 5 with labeling substance which is bound to avidin
with either avidin or enzyme-modified avidin when the CETP
standards are employed in Step 1, or the substrate suitable
for the enzyme activity assay systems when the human CETP
standard labeled by enzymes such as peroxides is used in
Step 1, if desirably together with the color developing
substance;
(Step 7) a step for reacting the enzyme bound to avidin
with the substrate suitable for the enzyme activity assay
system when enzyme-modified avidin is employed in Step 6;
(Step 8) a step for terminating both enzyme reaction and
color development by adding the terminator solution into
the monoclonal antibody immobilized microplate; and
(Step 9) a step for determining the absorption intensity,
fluorescence intensity or luminescence intensity.
The monoclonal antibody #72-1, #86-2, and #176-1 may
be used in the above-mentioned examples, however, the
monoclonal antibody #72-1 is preferable.
The term "affinity chromatography" in the present
invention means the chromatography for separation or
purification of human CETP contained in a sample by using
the affinity between the antigen and antibody. As the
examples of the sample, body fluids such as plasma, culture
supernatants, or cetrifugation suprenatants are given.

Specifically, the following two methods are given as
examples.
(1) A chromatography for separating the human CETP in
the sample, wherein the sample is applied to the above-
mentioned insoluble carrier such as filter or membrane for
immobilizing the monoclonal antibody having reactivity to
human CETP or its fragment of the present invention to
separate the human CETP.
(2) A chromatography for separating or purifying the
human CETP in the sample, wherein the sample is applied to
the above-mentioned insoluble carrier for immobilizing the
monoclonal antibody or its fragment, and the carrier is
packed into the column for applying the sample to elute to
separate or purify the human CETP.
In this method, as the example of the insoluble
carriers, cellulose type, agarose type, polyacrylamide
type, dextran type, polystyrene type, polyvinyl alcohol
type, polyamino acid type ones and so forth are given. The
monoclonal antibody or its fragment are immobilized on the
insoluble carrier by means of the known method such as
physical adsorption, polymerization by cross-link, trapping
in the carrier matrix, or immobilization by non-covalent
bond. Such carriers are packed into the columns such as a
glass, plastic and stainless column having the
configuration such as cylindrical one. Particularly, the
latter chromatography is referred to as the affinity
chromatography here.
As the insoluble carriers for the affinity
chromatography, any types of those may be used when they

can immobilize the monoclonal antibody or its fragment of
the present invention on them. As the examples,
commercially available carriers such as Sepharose 2B,
Sepharose 4B, Sepharose 6B, CNBr-Sepharose 4B, AH-Sepharose
4B, CH-Sepharose 4B, Activated CH-Sepharose 4B, Epoxy-
activated Sepharose 6B, Activated thiol-Sepharose 4B,
Sephadex, CM-Sephadex, ECH-Sepharose 4B, EAH-Sepharose 4B,
NHS-activated Sepharose, Thiopropyl Sepharose 6B, and so
forth(Pharmacia); Bio-gel A, Cellex, Cellex AE, Cellex-CM,
Cellex PAB, Bio-gel P, Hydrazide Bio-Gel P, Aminoethyl Bio-
Gel P, Bio-Gel CM, Affi-Gel 10, Affi-Gel 15, Affi-Prep 10,
Affi-Gel Hz, Affi-Prep Hz, Affi-Gel 102, CM Bio-Gel A,
Affi-Gel heparin, Affi-Gel 501, or Affi-Gel 601, and so
forth(Bio-Rad); Chroma-Gel A, Chroma-Gel P, Enzafix p-Hz,
Enzafix P-SH, Enzafix P-AB, and so forth(Wako Pure
Chemicals); Ae-Cellulose, CM-Cellulose, PAB Cellulose, and
so forth(Serva) are given.
"Mice introduced DNA encoding human CETP" may be
produced by the techniques employed generally in the field
of the transgenic mouse production (See The newest animal
cell experiment manual, AIC press, Chapter 7, pp. 361-408,
1990).
Tall et al. reported that they produce a transgenic
mouse introduced human CETP gene. However, the mouse can
not secrete CETP in blood when it requires extrinsic or
artificial induction such as taking foods supplemented
zinc. In contrast, the transgenic mouse of the present
invention secretes human CETP constantly without any

induction described above, and such a transgenic mouse is
not reported.
"Pharmaceutical composition" contains the monoclonal
antibody or its fragment of the present invention, and may
contain pharmaceutically acceptable carriers such as
excipients, diluent, vehicles, disintegrators, stabilizers,
preservatives, buffering agents, emulsifiers, aromatics,
coloring agents, sweetening agents, thickning agents,
fravering agents, solubilizing agents, or other additives.
Such pharmaceutical preparations may be formed as tablets,
pills, powders, granules, injections, liquid preparations,
capsules, troches, elixirs, suspensions, emulsions, or
syrups. The pharmaceutical preparations may be
administrated via oral or parental.
In particular, the injections may be prepared by
dissolving or suspending the pharmaceutical preparations in
the pharmaceutically acceptable carrier without toxicity at
the certain concentration. The carrier may be
physiological saline, distilled water for injections. The
certain range is from 0.1 µg of the monoclonal antibody/ml
of carrier to 10 mg of the antibody/ml of carrier. Such
injections may be administrated to patients need treatment
at the dosage of 1 µg to 100 mg/kg of body weight,
preferably at 50 µg to 50 mg/kg of body weight for one to
several times per day. This administration is performed
via clinically suitable routes such as intravenously,
subcuteneously, intradermally, in intramuscle, in
intraperitoneal and so forth. Preferable is intravenous
administration.

The present invention may be applied to not only
hyperlipidemia but also atherosclerosis caused by the
abnormal kinetics of CETP, prevention and/or treatment of
various diseases such as hyperalphalipoproteinemia or
hypercholes terinemia.
(Examples)
The present invention was explained in detail
hereinbelow based on the following working Examples.
However, the present invention is not limited to such
examples.
(Example 1) Establish of CETP activity assay system
In the present invention for determining the CETP
activity (cholesterol ester (abbreviated as CE) transporting
activity), the assay system constructed as described below
was employed unless it was specially stated. The assay
system of the present invention is a modified one according
to the method of Alberts et al., Arteriosclerosis, vol. 4,
49-58(1984). Briefly, the assay system was as follows.
Firstly, a donor lipoprotein comprising high density
lipoprotein in which radio-labeled cholesterol ester (HDL3)
was incorporated. An acceptor lipoprotein comprising low
density lipoprotein (LDL), and a sample containing CETP for
assay were mixed to physiologically react with each other.
Then, the amount of labeled CE transported from the donor
lipoprotein to the acceptor lipoprotein was determined by
using either the decrease of the radioactivity of the donor
lipoprotein or increase of that of the acceptor lipoprotein
to determine CETP activity of CETP in the sample.

Preparation of donor lipoprotein
Potassium bromide(KBr) was added to 20 ml of healthy
volunteer plasma to adjust its comparative gravity, d=1.125
g/ral. After that, the plasma was subjected to density
gradient centrifugation by 227,000 x g at 4°C for 17 hours,
and then obtained the fraction of which comparative gravity
was d>1.125 g/ml(HDL3 fraction). The fraction obtained was
dialyzed against TBS(0.15 M NaCl/10 mM Tris(pH 7-4)).
Then, 10 nM of tritium labeled cholesterol([3H]C, specific
activity 50.3 Ci/mM) was gradually dissolved in 95 %
ethanol with stirring slowly. The solution was incubated
for 18 hr at 37°C. During the incubation, tritium
cholesterol ([3H]C) attached onto the surface of HDL3 was
esterified by Lecithin Cholesterol acyltransferase(LCAT) to
be converted to tritium labeled cholesterol ester([3H]CE).
Then [3H]CE was incorporated into HDL3.
KBr was added into the human plasma to adjust its
comparative gravity, d=1.21 g/ml. After that, the plasma
was subjected to density gradient centrifugation by 227,000
x g at 4°C for 20 hours, and then obtained the fraction of
which comparative gravity was d fraction obtained was dialyzed against TBS described
before, and then obtained HDL3([3H]CE~HDL3; comparative
gravity is 1.125 dpm/nM). This fraction was used as the donor lipoprotein.
Preparation of acceptor lipoprotein
Potassium bromide (KBr) was added to 100 ml of healthy
volunteer plasma to adjust its comparative gravity, d=1.019
g/ml. After that, the plasma was subjected to density

gradient centrifugation by 227,000 x g at 4°C for 20 hours,
and then obtained the fraction of which comparative gravity
was d>1.019 g/ml. The fraction obtained was dialyzed
against TBS described above. Then, KBr was added again to
adjust the gravity d=1.063 g/ml. The solution was
subjected to the density gradient centrifugation by 227,000
x g at 4°C for 20 hr, and then obtained the fraction with
d TBS described above, and then obtained the fraction
comprising LDL(the comparative gravity:1.019 used acceptor lipoprotein).
Determination of CETP activity
The donor lipoprotein obtained in Example 1>( [3H]CE-HDL3 which contains 0.21 jig of cholesterol), the
acceptor lipoprotein(LDL which contains 21 µg of
cholesterol), and a sample for assay were mixed in a
microtube. Then, TBS described above was also added into
the microtube to adjust the ratio of cholesterol content in
the donor lipoprotein to that in the acceptor lipoprotein
equals to 1:100, and the ratio of cholesterol in HDL
contained in the assay sample to that in the donor
lipoprotein equals at least 1:10(total volume is 600
µl/tube). The tube was incubated for 15 hr in water bath
at 37°C. Then, the tube was transferred onto ice for 15
minutes. After that, 400 µl of the iced TBS and 40 µ1 of 1
% dextran sulfate solution containing 0.5 M MgCl2 were
added into the microtube, and vigorously vortexed. The
microtube was incubated for 30 minutes on ice. Then, the
tube was subjected to centrifugation by 8,000 x g at 4°C

for 10 minutes, and then recovered HDL rich supernatant.
The radioactivity in the supernatant was measured by means
of a Scintillation counter.
In order to determine CETP activity of the assay
sample contained CETP, the radioactivity of the control
sample which does not contain the assay sample was also
measured by treating as the same as the procedure described
above. CETP activity was determined based on the decrease
of the radioactivity by comparing to that in the assay
samples to that in the control sample. The activity was
expressed as unit, and the CETP activity for transporting 1
nM of cholesterol per one unit time was represented as 1
unit(U).
(Example 2) Preparation of purified CETP derived from
human
The procedure described below was performed at 4°C or
in ice bath according to the known method.
Dextran sulfate treatment
The peripheral blood was obtained from healthy
volunteers. Red blood cells in the blood were removed by
the centrifugation by the known method, and then obtained 1
L of human plasma. Two liters of distilled water, 100 ml
of 10 % dextran sulfate having molecular weight of 500,000
Da, and 80 ml of 4 M CaCl2 were added into the obtained
plasma with gentle stirring on ice bath for 15 minutes.
The mixed solution was centrifuged by 15,200 x g for 1 hr
to fractionate insoluble dextran sulfate/lipoprotein
complex as precipitate. The supernatant was collected, and
27.2 % BaCl2 was added to adjust the final concentration of

the solution to 1.36 %. The mixed solution was stirred for
20 minutes, and then centrifuged by 15,200 x g for 1 hr.
The precipitate was removed, and the supernatant was
collected.
Purification by phenyl Sepharose column
chromatography
Three molar of NaCl, 0.01 % sodium azide(NaN3), 50
pg/ml of Gentamysin sulfate, and 0.05 % ethylenediamine
tetraacetic acid(EDTA) were added into the supernatant
obtained in Example. The mixture was adjusted to pH
7.4. Phenyl Sepharose HP column(10 x 12.5 cm, Pharmacia
Biotech) was equilibrated with 3 M NaCl(pH 7.4) containing
0.01 % NaN3, 50 µg/ml of Gentamysin sulfate, and 0.05 %
EDTA as mentioned above. The mixture was applied into the
phenyl sepharose column. After that the column was washed
with 3 L of 0.15 M NaCl solution(pH 7.4), subsequently with
3 L of the solution without NaCl(pH 7.4), and then eluted
with 20 % ethanol. The elution profile was monitored by
using absorbance at 280 nm.
The result was shown in Fig. 1. Based on the elution
profile, active fractions containing CETP derived from
human was collected.
Purification by means of Resource Q column
choromatography
The active fractions collected in Example was
dialyzed against the buffer(pH 7.4) comprising 25 mM NaCl
and 10 mM Tris-HCl. Then, the dialyzed fraction was
applied to Resource Q column(3.5 x 10 cm, Pharmacia
Biotech) equilibrated with buffer. The column was washed

with 300 ml of the above-mentioned buffer, and eluted with
2 L of 25-250 mM gradient NaCl(pH 7.4). The elution
profile was monitored by absorbance at 280 nm.
The result is shown in Fig. 2. Based on the elution
profile, active fractions containing CETP derived from
human was collected to obtain purified CETP derived from
human.
(Example 3) Preparation of anti-human CETP monoclonal
antibody
Human CETP monoclonal antibody was prepared according
to the known method described in references such as
Experimental Medicine suppl. "Cell Technology Handbook"
(Toshio Kuroki et al. ed., pp. 66-74, Yodo press(1992)) or
An introduction of monoclonal antibody experimental
procedure(Tamio Ando et al., Kodansha(1991)).
Immunization, cell fusion, and cloning
Purified human CETP prepared in Example 2 with
Freund"s complete adjuvant was injected into foot pads of
BALB/c mice (female, 4-5 week age, purchased from Shizuoka
experimental animal center) for the first immunization. Day
5th, 10th, 15th from the first immunization, the purified
human CETP was injected into the foot pads of the immunized
mice as the additional immunization. Furthermore, the
purified human CETP was given similarly to the mice as the
final immunization before one or two days from the day that
the preparation of monoclonal antibody producing hybridoma
was performed. Lymph nodes of knee was excised from the
mice by a surgical operation according to known methods.
The lymphocytes obtained from the lymph node and mouse

myeloma cells, PAI were fused by using polyethylene glycol
4000 as a fusion agent (at the ratio of 3:1). Then, the
hybridomas were cultured in ASF104 medium(AGF) comprising
HAT with aminopterine containing 10 % fetal calf serum.
Then the media was changed to HT medium without
aminopterine to select the hybridoma prepared by fusion of
the lymphocytes and the myeloma cells. The number of
obtained clones was 169.
Screening of hybridoma
Hybridoma producing anti-human CETP monoclonal
antibody was screened by the CETP activity assay system
established in Example 1.
The purified human CETP prepared in Example 2 and each
culture supernatant of the hybridoma screened(60 µl) were
added into the mixture of the donor lipoprotein prepared in
Example([3H]CE-HDL3 containing 0.21 µg of cholesterol)
and the acceptor lipoprotein prepared in Example (LDL
containing 21 µg of cholesterol). Then, TBS was added to
prepare the total volume of 600 µl/tube.
The prepared solution was treated similarly to the
procedure described in Example. The activity of CETP
was determined in each sample by comparing with the
activity of the control sample to obtain the CETP
inhibition activity(inhibition activity against CE-
transporting activity of CETP) in the culture supernatant
of the hybridoma. By means of the screening, three
positive clones, #72-1, #86-2, and #176-1, which have
different CETP inhibition activities were obtained.

Two hybridoma, #72-1 and #86-2 were deposited to
National Institute of Bioscience and Human-Technology
Agency of Industrial Science and Technology at the date of
Dec. 20, 1994, and International accession numbers are FERM
BP-4944 and FERM BP-4945, respectively.
Large scale preparation of monoclonal antibody
Each of the hybridoma #72-1, #86-2, or #176-1 (106 to
107 cells/0.5 ml/mouse) were administrated to 15 of ICR
nude mice(female, 7-8 week age, purchased from Charles
River) via intraperitoneally. Ten days later, ascites were
collected from the mice anesthetized according to the known
method. The monoclonal antibodies were prepared in large
scale as supernatants of centrifugation.
Isotyping
Isotyping for the monoclonal antibodies, #72-1, #86-2,
and #176-1, were performed with Mouse monoclonal antibody
isotyping kit(Amersham) according to the protocol
supplemented to the kit. The result showed that both #72-1
and #86-2 were IgGl, and #176-1 was IgG2b.
Purification of the monoclonal antibody
Five ml of the each monoclonal antibodies, #72-1, #86-
2, and #176-1, prepared as the supernatant, were diluted by
triple times with 0.06 M acetate buffer(pH 4.0), and pH was
adjusted to 4.8 with 1 N HC1. Then, 16.5 pi of caprilyc
acid(Wako Pure Chemical) was gradually added into the
diluted solution at room temperature to react for 30
minutes. After that, the mixture was centrifuged by 10,000
rpm for 20 minutes to precipitate proteins except
antibodies. Supernatants were collected, and filtrated

with the filter(Millipore) to remove white precipitates.
Filtrates were dialyzed against phosphate buffer for 2 hr.
After dialysis, ammonium sulfate(26.2 g/100 ml) was
added little by little with stirring to react at 4°C for
120 minutes. Then, the mixture was centrifuged by 10,000
rpm for 20 minutes to collect precipitates. Phosphate
buffer was added to the precipitate, and dialyzed against
to phosphate buffer at 4°C for 24 hr, and then obtained the
purified monoclonal antibody, #72-1, #86-2, and #176-1,
respectively.
(Example 4) Purification of human CETP by affinity
chromatography
The purified human CETP prepared in Example 2 was
further purified by means of the affinity column
chromatography which used the monoclonal antibody, #72-1,
and then characterized.

Preparation of immobilized monoclonal antibody as a
adsorbent media for column packing
HiTrap-NHS-activated Sepharose HP column(1 ml, Pharmacia
Biotech) was employed, and the experiment operation was
performed according to the attached protocol. The
monoclonal antibody, #72-1, was dissolved in 0.2 M sodium
hydrogen carbonate(pH 8.3) containing 0.5 M NaCl was
injected into the column at the ratio of 5 mg/ml. Then,
the monoclonal antibody was reacted with the column for 45
minutes to immobilize onto NHS-activated Sepharose to
prepare the immobilized monoclonal antibody #72-1.
Purification by affinity chromatography

A solution containing the purified human CETP obtained
in Example 2 was applied on the column prepared in
Example. Then, the column was washed with 5 ml of 50
mM Tris-HCl buffer(pH 7.6) containing 500 mM NaCl, and
eluted with 2 mM glycine-HCl(pH 2.8). The eluted fraction
was neutralized with 2 M Tris-HCl(pH 8.8). The elution
profile was monitored by absorbance at 280 nm. The
result was shown in Fig. 3. Based on the elution profile,
active fractions containing human CETP were pooled. The
pooled fraction were dialyzed against 50 mM Tris-HCl
containing 0.15 M NaCl(pH 7.6), and the highly purified
human CETP was prepared.
Characterization of purified human CETP
As described in Fig. 3, enzyme activity (specific
activity) of CETP obtained in Example 4 was 1,100 U/mg.
The molecular weight of the purified human CETP was
analyzed by using SDS-PAGE(sodium dodecyl sulfate
polyacrylamido gel electrophoresis).
The result was shown in Fig. 4.
It was confirmed that the purified human CETP obtained
in Example 4 comprises two proteins with about 63,000 Da
and 61,000 Da. Many researchers tried to purify the human
CETP, and the values of the molecular weight were reported.
Such values were not identical each other, because the
purification method, purity of the protein and/or analysis
of the molecular weight were different. However, they are
in the range of about 64,000 to 66,000 Da. Compared to
such values, it was demonstrated that the purity of the
CETP obtained in Example 4 was very high.

(Example 5) Characterization of Anti-human CETP monoclonal
antibody
Reactivity to the human CETP
The reactivity of each of the purified monoclonal
antibodies, #72-1, #86-2, and #176-1, prepared in Example 3
was confirmed by determining human CETP transporting
activity assayed by means of CETP activity assay system
established in Example 1 as the same as Example.
The purified human CETP prepared in Example 4, and
each of the monoclonal antibodies, #72-1, #86-2, and #176-
1, which were diluted with Tris-HCl buffer(pH 7.4)
containing 0.15 M NaCl at the various concentration, were
added into the mixture of the donor lipoprotein([3H]CE-HDL3
containing 0.21 g of cholesterol) prepared in Example
and the acceptor lipoprotein(LDL containing 21 ^g of
cholesterol) prepared in Example. Then TBS was
further added to prepare the total volume of 600 µl/tube.
The prepared solution was treated similarly to the
procedure described in Example. The CETP activity of
each sample and the control without the monoclonal antibody
were determined. Comparing the values of the corresponding
samples, the CETP inhibition activity of each monoclonal
antibody was determined. As the reference, mouse IgG was
also used. The result is shown in Fig. 5.
The monolonal antibody, #72-1, showed dose-dependent
inhibition of the human CETP activity, particularly, the
human CETP activity was inhibited 100 % at the
concentration equal to or more than 10 µg/ml. In contrast,
the monoclonal antibody, #86-2, did not show dose-dependent

inhibition. This monoclonal antibody showed the maximum
inhibition(58 %) at the concentration about 0.5 /jg/ml;
however, it did not show any inhibition at the
concentration equal to or more than 17 µg/ml. The
monoclonal antibody, #176-1, did not show dose-dependent
CETP inhibition activity, neither did #86-2, and it showed
the maximum inhibition(50 %) at the concentration of about
1.0 ^g/ml.
Based on the above results, it was demonstrated that
the epitope recognized by the monoclonal antibody #72-1 was
different from that recognized by other monoclonal
antibodies, #86-2 or #176-1 with high possibility.
Reactivity for rabbit CETP
The respective reactivity of the monoclonal
antibodies, #72-1, #86-2, and #176-1 prepared in Example 3
for the rabbit CETP was confirmed by means of the CETP
activity assay system similar to that of Example 1. The
purified rabbit CETP, the donor lipoprotein and the
acceptor lipoprotein used for the assay system were
prepared as described below.
Preparation of the purified rabbit CETP
The following procedure was performed according to the
known method at 4°C or in ice bath.
(1) Dextran sulfate treatment
Peripheral blood was obtained from plural
rabbits(Japan white, Kitayama rabes). The blood was
centrifuged to remove red blood cells according to the
conventional method, and one hundred ml of rabbit plasma
was obtained. Two hundred ml of distilled water, 10 ml of

10 % of dextran sul fate (molecular weight 500,000 Da), and
7.9 ml of 4 M CaCl2 were added into the 100 ml of the
plasma obtained, and gently stirred in ice bath for 15
minutes. The mixture was centrifuged by 20,000 x g for 20
hr at 4 °C to fractionate the insoluble dextran
sulfate/lipoprotein complex, and then collected the
supernatants.
(2) Purification by Phenyl Sepharose column chromatography
Three molar of NaCl, 0.01 % NaN3, 50 µg/ml of
Gentamysin sulfate, and 0.05 % EDTA were added to the
supernatant obtained, and adjusted pH 7.4. Prior to apply
the mixture, Hiload 26/10(Phenyl Sepharose column,
Pharmacia Biotech) was equilibrated with the same solution
described above. Then, the mixture was applied on the
column, and washed with 0.15 M NaCl solution (pH 7.4)
containing the same concentration of NaN3, Gentamysin
sulfate and EDTA. After that, adsorbed components were
eluted by using the solution without NaCl and 20% ethanol.
The elution profile was monitored absorbance at 280 nm.
The result is shown in Fig. 6. Based on the elution
profile, the active fractions containing rabbit CETP were
pooled.
(3) Purification of Blue Sepharose column chromatography
The active fractions pooled in the above (2) was
dialyzed against 50 mM HEPES buffer(N-2-
hydroxyethylpiperadine-N" -2-ethanesulfonic acid) (pH 7.0).
Then, the dialyzed sample was applied on Blue Sepharose
column(CL-6B, 1.5 x 8.5 cm, Pharmacia Biotech) which was
equilibrated with the buffer. The column was washed with

the buffer, and then eluted with the solution containing
1.5 M NaCl and the buffer(pH 7.0). The elution profile was
monitored by absorbance at 280 nm.
The result is shown in Fig. 7. Based on the elution
profile, the active fractions containing rabbit CETP were
pooled.
(4) Purification by succinylated LDL Sepharose column
chromatography
The active fractions pooled in the above (3) was
dialyzed against the 50 mM HEPES buffer(pH 7.4). Then,
succinylated LDL Sepharose column was prepared by using
succinyl LDL and CNBr-activated Sepharose 4B(1.5 x 8.5 cm,
Pharmacia Biotech). The column was equilibrated with the
39 mM phosphate buffer containing 0.025 % EDTA and 60 mM
NaCl(pH 7.4). Then, the dialyzed sample was applied on the
column. The column was washed with the same buffer, and
then eluted with the buffer(pH 7.4) containing 0.01 % EDTA.
The elution profile was monitored by absorbance at 280 nm.
The result is shown in Fig. 8. Based on the elution
profile, the active fractions containing rabbit CETP were
pooled.
The donor lipoprotein and the acceptor lipoprotein
According to the similar method described in both
Example and , both the donor lipoprotein([3H]CE-
HDL3 containing 0.21 µg cholesterol) and the acceptor
lipoprotein(LDL containing 21 µg of cholesterol) were
prepared by using the rabbit plasma.
Confirmation of the reactivity for rabbit CETP

The respective reactivity of the monoclonal
antibodies, #72-1, #86-2, and #176-1 against the rabbit
CETP was confirmed by means of the CETP activity assay
system in which purified rabbit CETP prepared in ,
and the donor lipoprotein prepared and the acceptor
lipoprotein prepared in were used as the same as
that of Example .
The result is shown in Fig. 9. Neither monoclonal
antibody #86-2 nor #176-1 showed rabbit CETP inhibition
activity independent of their concentration. Accordingly,
these monoclonal antibodies did not have the specific
reactivity for the rabbit CETP. Furthermore, the
monoclonal antibody #72-1 did not show the detectable
reactivity at the concentration equal to or less than 3
fig/ml.
(Example 6) Preparation of antibody fragments, F(ab")2 and
Fab
The F(ab")2 and Fab of the purified monoclonal
antibodies prepared in Example 3, #72-1, #86-2, and #176-1
were prepared as follows.
Each of the monoclonal antibodies was added into 20 mM
acetate buffer(pH 3.5) at the concentration of 5 mg/ml
respectively, and incubated for 30 minutes. Then, one ml
of insolubilized pepsin (Pierce) was added to the incubated
solution, and further incubated for 12 hr at 37°C rotating
by using a rotator. After that, the reaction mixture was
centrifuged by 3,000 rpm for 10 minutes at 4 °C to collect
supernatants as the first supernatant.

The supernatant was subjected to the Protein A
affinity chromatography by using Protein A column
kit (Amersham), and the procedure was performed acceding to
the attached protocol. A binding buffer was added to the
precipitate to suspend, and then the suspension was
centrifuged by 3,000 rpm for 10 minutes at 4 °C to collect
supernatants as the second supernatant. Both the first and
second supernatant were pooled, and the same amount of the
binding buffer was added. Then, 1 N sodium hydroxide was
added to adjust pH 8.9. Protein A Sepharose column was
equilibrated with the binding buffer prior to applying the
mixture. The column was washed twice with 5 ml of the
binding buffer, and then the eluted fractions were
obtained. The eluted fractions were dialyzed against 2 L
of 5 mM phosphate buffer pH 6.8 for 24 hr at 4°C.
Further purification, the dialyzed sample was
subjected to HPLC by using Hydroxyl apatite column(Bio
Rad). The dialyzed sample was applied onto the Hydroxyl
apatite column. Then, the column was washed with 5 mM
phosphate buffer for 5 minutes. Retained components in the
column were subsequently eluted, with gradient elution
buffer of 5 mM to 0.4 M phosphate buffer. The eluents were
fractionated by using a fraction collector. The elution
profile were monitored by absorbance at 280 nm to monitor
the amount of F(ab")2 contained in the fracitions to pool
the active fractions. The pooled fractions were dialyzed
against 2 L of phosphate buffer at 4 °C for 24 hr to obtain
the respective F(ab")2 of the monoclonal antibodies, #72-1,
#86-2, and #176-1.

(Example 7) Establishment of human CETP assay method by
using sandwich ELISA
Preparation of the solid phase with immobilized
monoclonal antibody
Each of the purified monoclonal antibodies, #72-1,
#86-2 and #176-1 prepared in Example 3 were diluted with
phosphate buffer(pH 7.4) so as to be 10 ng/well to 1
µg/well. Fifty pi of the diluted antibody solutions were
added into wells of 96 well microtiter plates for
ELISA(Corning). The plates with the solutions were
incubated at 4°C for 24 hr to adsorb each monoclonal
antibody onto the inside of the well. Then, the well was
washed with 300 jjI of phosphate solution containing 0.1 %
Tween 20 for four times. After discarded the phosphate
buffer, 300 µl of the blocking agent, Block Ace(Dainippon
Pharmaceutical), was added to the well to incubate for 2 hr
to block the antibody unbound sites. Each well was washed
with 300 µl of phosphate solution containing 0.1 % Tween 20
for four times.
Preparation of labeled monoclonal antibodies
One mg/ml of each of the purified monoclonal antibody
solutions, #72-1, #86-2 and #176-1, prepared in Example 3
were dialyzed against 0.1 M NaHCO3(pH 8.2 to 8.3) at 4 °C
for 24 hr. Then, one hundred pi of NHS-biotin(2 mg/ml,
Funakoshi) was added into the dialyzed antibody solution,
and stirred vigorously. The antibody solution was
incubated for 4 hr at room temperature. After that the
antibody solution was dialyzed against phosphate buffer at
4 °C for 4 hr.

Establishment of the assay method by using sandwich
ELISA
The human CETP assay method by using sandwich ELISA
established of the present invention was as follows.
Each of the monoclonal antibodies, #72-1, #86-2, and
#176-1 was immobilized respectively onto the microplates at
the concentration of 10 ng/well to 1 ^g/well as described
in . The above-mentioned microplates prepared was
referred to as the immobilized microplate. The immobilized
plates were washed with phosphate buffer containing 0.1 %
Tween 20 for 3 times. Phosphate buffer containing 10 %
Block Ace was used for diluting the samples which were the
purified human CETP standard prepared in Example , the
plasma of healthy volunteers without lipoprotein prepared
in Example , or the plasma of various patients. The
immobilized plates with 100 µl of the diluted samples were
incubated at room temperature for 1 hr. The plates were
washed with the phosphate buffer containing 0.1 % Tween 20
for three times. The biotin labeled monoclonal antibodies,
#72-1, #86-2, or #176-1, prepared in Example were
diluted with the phosphate buffer containing 10 % Block Ace
to 3 ng to 1 µg/50 µl/well. Then, the plates with 50 µl of
the biotin labeled monoclonal antibodies were incubated at
room temperature for 1 hr. After that, the plates were
washed with the phosphate buffer containing 0.1 % Tween 20
for 3 times. Fifty µl of streptoavidin-ß-
galactosidase(Gibco BKL) diluted 1,000 times with 20 mM
HEPES buffer containing 0.5 M NaCl(pH 7.0) was added into

each well of the immobilized plates. Then, the immobilized
microplates were incubated at room temperature for 1 hr.
The immobilized microplates were washed with the
phosphate buffer containing 0.1 % Tween 20 for three times.
After that, fifty µ1 of 0.015 % or 0.01 % of 4-methyl-
umbelliferyl-ß-D-galactoside(Sigma) diluted with 10 mM
phosphate buffer containing 1 mg/ml of BSA, 100 mM NaCl, 1
mM MgCl2(pH 7.0) was added into each well of the
immobilized microplates. Then, the immobilized microplates
were incubated at room temperature for 10 or 20 minutes.
After that, one hundred jvl of Na2CO3 solution was added
into the wells to terminate the reaction. Intensity of the
wells were measured with Fluoroscan II microplate
fluorometer(Flow Laboratories) at 460 nm of the emission
wave length and the 355 nm of excitation one. The amount
of CETP in the sample was determined from the calibration
curve obtained in the following Example. The results of
the assay when various combination of the monoclonal
antibodies(#72-1, #86-2, and #176-1) immobilized or labeled
are shown in Figs. 10 to 12. As a result, it was confirmed
that the above-mentioned monoclonal antibody amount were
quantitatively determined when the different monoclonal
antibodies immobilized or labeled were combined, for
example, #72-1 and #86-2, or #72-1 and #176-1.
The optimal concentration of the immobilized or the
labeled monoclonal antibody were determined under the
following conditions. As the substrate, 4-methyl-
umbelliferyl-ß-D-galactoside was used, and as the assay

sample, the plasma from the healthy volunteers without
lipoprotein prepared in Example 2 was used.
(1) the immobilized monoclonal antibody:
#72-1(10 ng to 1 µg/well)
the labeled monoclonal antibody:
#86-2 or #176-1(10 ng to 1 µg/well)
substrate concentration: 0.01 %
reaction time: 10 minutes
(2) the immobilized monoclonal antibody:
#72-1(1 µg/well)
the labeled monoclonal antibody:
#86-2(1 to 3 ng/well)
substrate concentration: 0.015 %
reaction time: 20 minutes
The result are shown in Figs. 13 to 17.
As shown in Figs. 13 to 17, the optimal concentration
of the immobilized monoclonal antibody, #72-1 was 1
jig/well(20 µg/ml). That of the labeled monoclonal
antibody, #86-2 was 100 ng/well(2 µg/ml) when the reaction
time was 10 minutes, and 3 ng/well(60 ng/ml) when the
reaction time was 20 minutes. Accordingly, the optimal
concentration of the labeled monoclonal antibody may be
changed since the concentration depends on the reaction
time for substrate.
In the following Examples, the sandwich ELISA was
employed, and the conditions were as follows:
the immobilized monoclonal antibody:
#72-1(1 µg /well (20 µg/ml))
the labeled monoclonal antibody:

#86-2(3 ng/well(60 µg/ml))
the reaction time for substrate: 20 minutes
Preparation of a calibration curve and confirmation
of accuracy

A calibration curve was prepared by using the sandwich
ELISA established in Example . As Standard, the
purified human CETP prepared in was used. As the
immobilized monoclonal antibody, #72-1(1 µg/well), and as
the labeled one, #86-2(3 ng/well) were also used. The
result is shown in Fig. 18.
As shown in Fig. 18, the calibration curve was almost
linear at the range of very low concentration between 0.4
to 1.25 ng/ml(correlation coefficient: r=0.995). The
determination limit (the detection limit) of the sandwich
ELISA of the present invention was 0.4 ng/ml. Accordingly,
it was demonstrated that the sandwich ELISA of the present
invention had excellent sensitivity of determination, that
is, excellent sensitivity of detection.
Calculation of coefficient of variation
In order to study the accuracy of the assay method of
the present invention, the coefficient of variation(c.v.)
among 48 wells in a 96 well plate or different 6 plates was
calculated. The c.v. obtained in the same plate was 7.06
%, and that obtained in different plates was 6.13 %.
Accordingly, it was demonstrated that the assay system by
using the sandwich ELISA of the present invention has high
accuracy.

Preliminary experiment for establishment of the
human CETP assay system
Study of the effect of the determination(assay)
capability by human plasma components
In order to study whether the plasma components which
interfere the human CETP determination was contained in
human plasma or not, the following tests were performed.
The purified human CETP prepared in Example with
either 0.735 µg/ml, or 1.469 µg/ml were added into the
plasma from the healthy volunteers prepared in Example 1> which contained 0.56 µg/ml of CETP. Then, The amount of
CETP was determined by using the method established in the
above-mentioned .
When 0.735 pg/ml or 1.469 pg/ml of CETP was added, the
total CETP amount of each sample before incubation was
calculated as 1.294 µg/ml or 2.029 µg/ml respectively. On
the other hand, the total amounts of CETP recovered were
1.440 µg/ml and 2.189 µg/ml, and the recovery percentages
were 111 % and 108 % respectively.
As a result, it was demonstrated that the human plasma
did not contain any component which interfere the
determination(assay) of CETP by the method of the present
invention. Accordingly, it was shown that the amount of
CETP in human plasma was accurately determined by using the
method of the present invention.
Effect of lipoproteins in human plasma
In order to study effect given by the substances
except CETP such as lipoproteins for the human CETP
determination, the human CETP with different purity as the

assay sample was determined by using the assay system
established in the .above-mentioned .
For the determination, the following samples were used
as the samples.
(1) the plasma without hemocytes by centrifugation
prepared in Example
(2) the plasma without lipoprotein finally prepared in
Example
(3) the purified CETP with the Phenyl Sepharose column
prepared in Example
(4) the purified human CETP prepared in Example
The result is shown in Fig. 19. Dilution curves
obtained were respectively parallel with that of the
purified human CETP(4).
As a result, it was demonstrated that the lipoproteins
in human plasma did not interfere the determination of CETP
by the method of the present invention. Accordingly, it
was shown that the determination method of the present
invention may be apply to plasma irrespective of the
sample"s purity.
Correlation of CETP contents and CETP activities
In order to investigated the precision of the
determination method of the present invention, the
correlation between the determined CETP amount in the human
plasma sample and the CETP activity of the plasma sample
per se was investigated.
CETP contents were determined by using the plasma
without lipoproteins obtained in Example as the assay
sample. CETP activity was measured by using the same

plasma sample with the CETP assay system of Example 1. The
result is shown in Fig. 20.
Since correlation coefficient(r) obtained was 0.953,
the amount of CETP determined by the method of the present
invention and the CETP activities of the same sample show
good correlation. As a result, it was demonstrated that
the assay system of the present invention has quite high
precision.
(Example 8) Determination of the human CETP in human
plasma
The amounts of CETP of from the healthy volunteers or
various patients were determined by using the sandwich
ELISA method established in Example .
The CETP activity of the plasma was determined by
using the donor lipoprotein([3H]CE~HDL3 which contains 6 ^g
of CE) prepared similar to Example and the acceptor
lipoprotein (LDL which contains 600 yq of CE) prepared
similar to Example with the CETP assay system
established in Example .
The human plasma used in the assay were plasma from
the healthy volunteers (13), and patients of type Ha
hyperlipidemia(5), type lib hyperlipidemia(5), CETP
deficiency(2), LCAT deficiency(2), and hyperaplha-
lipoproteinemia(l). Results are shown in Fig. 21.
Any sample employed in the assay showed the good
correlation between the amount of CETP determined and CETP
activity. As expected, CETP was not detected in the plasma
form the patients of CETP deficiency. Furthermore, it was
demonstrated that the assay method of the present invention

may be applied on not only the plasma from healthy
volunteer but also the patients with various diseases.
(Example 9) Comparison with the conventional determination
method
The following tests were performed to study the
availability of the assay system of the present invention
comparing with the conventional method which employs
sandwich ELISA.
In the conventional method, treatments by detergents
such as TritonX-100 or heating is performed to expose
epitopes capped by the interaction between protein-protein
or protein-lipoprotein prior to the determination.
However, such treatment causes denaturation of the proteins
such as CETP in the sample, and the protein loses its
higher-order structure to become inactivate biologically.
Since CETP detected or determined by the conventional
method was not an intact one, but denatured one, it was
impossible to determine the accurate amount of CETP in the
plasma.
Accordingly, the followings were used as the sample in
this determination.
(1) the plasma from healthy volunteer without
lipoprotein prepared as the same as Example
(2) the plasma from healthy volunteer without
lipoprotein incubated with 0.1 % Tween 20
(3) the plasma from healthy volunteer without
lipoprotein heated at 95°C for 5 minutes
(4) the plasma from healthy volunteer without
lipoprotein incubated with 1 % Tween 100

The result was shown in Fig. 22.
CETP was essentially detected in all samples, (1) to
(4), however, it was not detected in both samples, (3) and
(4). Particularly, no CETP was detected in (3).
Furthermore, CETP activity was decreased more than 30 % in
the plasma treated with the low concentration of Tween 20.
Namely, intact CETP in the human plasma was not detected by
using the conventional determination(assay) method which
requires the detergent treatment or heating. However, it
could be determined precisely by using the assay system of
the present invention, since the monoclonal antibody has
the specific reactivity for intact CETP in the human
plasma. Furthermore, it was also demonstrated that the
known monoclonal antibodies for the human CETP react
specifically to the denatured human CETP, but not react to
human intact CETP.
(Example 10) Preparation of the pharmaceutical
compositions and their CETP inhibition activity
The purified monoclonal antibodies, #72-1, #86-2, and
#176-1 were dissolved in 10 ml of the distilled water for
injections to prepare injections at the concentration of 50
to 150 µg/wl.
Anti-rabbit CETP monoclonal antibody was prepared
similarly to Example 3 by using the purified rabbit CETP
prepared in Example as immunogen. Briefly, BALB/c
mice(female, 4-5 weeks, Shizuoka Experimental Animal
Center) was immunized with the immunogen to obtain two
hybridoma #2-64 and #9-1, which produced anti-rabbit
monoclonal antibody. Each hybridoma was transplanted into

nude ICR mice(female, Charles River) to prepare anti-rabbit
monoclonal antibodies from the ascites. The monoclonal
antibodies obtained, #2-64 and #9-1 were both IgGl. The
monoclonal antibody, #2-64 was dissolved into the distilled
water for injections at the concentration of 0.13 mg/ml.
The monoclonal antibody, #9-1, was at the concentration of
5.53 mg/ml. Thus prepared injections containing either #2-
64 or #9-1 was administrated into rabbit at the dose of 1.8
mg/kg of body weight via i.v. The time of initial
administration was time 0, and the monoclonal antibodies
were administrated as the same dose in every 24 hr. Blood
was sampled at 1, 2, 4 hr from the initial administration
to obtain plasma.
The CETP activities in the plasma thus obtained were
determined by using the sandwich ELISA for the rabbit CETP
determination method established with these monoclonal
antibodies, #2-64 and #9-1, similarly to Example 1.
It was demonstrated that the monoclonal antibodies,
#2-64 and #9-1, significantly inhibit CETP in rabbit
plasma.
(Example 11) Production of human CETP high expression
transgenie mice
The plasmid containing the cDNA encoding the human
CETP was obtained as follows. A cDNA fragment encoding the
human CETP was amplified by PCR with 5"-stretch cDNA
library of human liver(Clonetech) as a template. The PCR
products were separated by agarose gel electrophoresis with
the established known method. The cDNA fragment of
interest was excised from the gel followed by ligation

kit(Takara). The ligated plasmid was introduced into E.
coli DH5 to obtain enough amount of plasmid to perform DNA
sequencing. After sequencing, the human CETP cDNA was
confirmed.
cDNA encoding the human CETP obtained above was
treated with DNA ligation kit(Takara), and inserted into a
vector containing human ß-actin promoter(Mol. Cel.
Immunol., 4:1961-1969(1984); ibid., 5:2720-2732(1985)) to
obtain the plasmid, pCETP-1. By electroporation, pCETP-1
was introduced into COS cells, and then obtained the RNA of
transformed COS cells according to the known method. RT-
PCR was performed by using the RNA to confirm the specific
transcription of human CETP in COS cells introduced pCETP-
1. Another transformant was produced similarly to the COS
cells by using the expression vector pME 18S. The
expression of human CETP in the trans formant was assayed by
using the sandwich ELISA established in Example 7. In
order to produce transgenic mice, the plasmid, pCETP-1 was
enzymatically treated so as to linear.
ICR white mice having vaginal plug(female, Japan Crea)
were employed as foster mice, . This mouse was obtained by
mating a female ICR mouse with a male ICR mouse with
seminal duct ligation(Japan Crea). C57BL/6J mice(female,
Japan Crea) were employed as mice for collection of embryo
for human CETP gene transduction. This mouse was obtained
by mating male C57BL/6J mouse with a female C57BL/6J mouse
given both 5 unit of PEAMEX and the same unit of
PUBEROGEN(both from Sankyo) for superovulation. After
mating, oviducts were excised from the female C57BL/6J

mouse to be treated with hyaluronidase to obtain embryo
alone to store in media.
Introduction of human CETP gene into the embryo was
performed by using a manupilater under a microscope
according to the known method. The embryo was retained by
holding pipette at 37°C. The solution containing the
linear gene of human CETP prepared before was introduced
into male pronucleus of the embryo by using injection
pipette.
After introducing the gene, embryos holding normal
condition were selected to be introduced into the oviducts
of the tentative parent mouse, ICR white mouse.
Tails of progeny mice from the parent mouse, which
were hetero mice, were cut off to investigate whether the
human CETP gene was introduced into the mouse genomic gene.
By using PCR method, this introduction into the mouse
genomic gene was confirmed, and the expression of the human
CETP was also determined by using the sandwich ELISA
established in Example 7.
Mating two hetero mice described above, the transgenie
mice which highly express human CETP was produced as homo
mice.
(Example 12) In vivo CETP inhibition of anti-CETP
monoclonal antibody
Two purified human anti-CETP monoclonal antibodies,
#72-1 and #86-2 prepared in Example 3 was dissolved in the
distilled water for injections at the ratio of
concentration 29:1 to prepare injections, respectively.

The prepared solution was administrated i.p. to 3 of
the female transgenic mice produced in Example 11 at the
dose of 100 mg/kg as single injection.. These mice were fed
pellet type food for breeding freely for 4 months.
Just before the antibody administration was time 0,
and blood was sampled at the time, 1, 3, 6, and 24 hr from
eyegrounds to separate plasma by centrifugation. The CETP
activity in the plasma obtained(CETP inhibition activity by
anti-human CETP antibody) was determined as the amount of
CE transportation from HDL to LDL by using the CETP
activity determination system established in Example 1.
The result is shown in Fig. 24.
It was confirmed that the monoclonal antibody of the
present invention completely inhibit the human CETP
activity in vivo. Furthermore, such inhibition effect for
the human CETP activity in vivo was firstly clarified by
this invention.
(Example 13) Prevention of atherosclerosis by anti-CETP
monoclonal antibody
Two purified human anti-CETP monoclonal antibodies,
#72-1 and #86-2 prepared in Example 3 was dissolved in the
distilled water for injections at the ratio of
concentration 29:1 to prepare injections, respectively.
The prepared solution was administrated i.p. to 3 of
the female transgenic mice produced in Example 11 at the
dose of 75 mg/kg per injection for 4 days. These mice were
fed pellet type food for breeding freely for 6 weeks.
PBS(Phosphate buffered saline) was administrated to other
mice as control.

Just before the antibody administreition was time 0.
Blood was sampled at the day -3, 2, 4, 3, and 11 from
eyegrounds to separate plasma by centrifugation. The
amounts of cholesterol in the plasma obtained was
determined by using lipoprotein determination kit(Liquitec
TC1/TC2, Boehringer Mannheim). For the fractionation of
HDL, HDL cholesterol separation reagent(Boehringer
Mannheim) was employed. The result is shown in Fig. 25.
It was demonstrated that HDL cholesterol level in
plasma was significantly enhanced when the anti-human CETP
monoclonal antibody of the present invention was
administrated in vivo. HDL was considered to be an
important protein having anti-arteriosclerosis effect. In
fact, it was showed that the development of atherosclerosis
legion was inhibited or recessed by enhancement of HDL in
plasma(J. Clin. Invest., 85:1234-1241(1990)).
The observation that the administration of anti-human
CETP antibody in vivo enhances the HDL cholesterol level in
plasma was clarified at first by the present invention.
Accordingly, the result of the above-mentioned test
revealed that the monoclonal antibody of the present
invention was available for prevention and/or treatment of
atherosclerosis.
INDUSTRIAL UTILITY
Since the anti-human CETP monoclonal antibody of the
present invention has higher binding specificity(CETP
inhibition activity) to human CETP, particularly intact
CETP in the human body fluid such as plasma, the above-
mentioned intact CETP per se may be determined convenient

and highly sensitive. Such determination(assay) method has
not been established before.
Particularly, by using the above-mentioned
characteristics of the any of three anti-human CETP
monoclonal antibodies of the present invention, the intact
CETP can be determined more convenient and sensitive when
any of the two monoclonal antibodies described above in
combination were employed in the sandwich ELISA.
In the determination method employing the monoclonal
antibody of the present invention, the amount of CETP in
bodily fluid such as plasma is determined conveniently with
high sensitivity without any pretreatment such as the
detergent or heat treatment.
Since the anti-human CETP monoclonal antibody of the
present invention has excellent CETP inhibition activity,
it was available as Pharmaceuticals for prevention and/or
treatment for various diseases such as atherosclerosis,
hyperlipidemia, and hyperalphalipoproteinemia caused by the
abnormal kinetics of CETP.
WE CLAIM:
1. An anti-human CETP monoclonal antibody or a F(ab")2 or Fab" fragment from said
monoclonal antibody,
wherein said monoclonal antibody inhibits cholesterol ester transfer activity of
human CETP and does not inhibit cholesterol ester transfer activity of rabbit CETP at a
concentration of 3 µg/ml or below, and
wherein said monoclonal antibody provides a lower detection limit in an
immunoassay of human CETP in non-pretreated human plasma than in human plasma
pretreated by detergent or heating.
2. The hybridomas # 72-1 or # 86-2 which respectively secretes monoclonal
/antibody reactive to human CETP wherein said hybridomas is selected from the group
consisting of the cell line deposited under the Accession number FERM BP-4944 and the
cell line deposited under Accession Number FERM BP-4945 respectively.
3. A recombinant chimeric monoclonal antibody or a F(ab")2 or Fab" fragment from
said monoclonal antibody, wherein said monoclonal antibodj" comprises a variable region
from the monoclonal antibody, as claimed in claim 1, and a constant region from a human
immunoglobulin.
4. A recombinant humanized monoclonal antibody or a F(ab")2 or Fab" fragment from
/ said monoclonal antibody,
wherein said monoclonal antibody comprises a part of or the whole of the
complementarity determining regions of the hypervariable region from the monoclonal
antibody as claimed in claim 1, framework regions of the hypervariable region from a
human immunoglobulin and a constant region from a human immunoglobulin.

5. An immobilized monoclonal antibody or immobilized antibody fragment -which is
prepared by immobilizing the monoclonal antibody or F(ab")2 or Fab" fragment as claimed
in claim 1 on an insoluble carrier.
6. The immobilized monoclonal antibody or immobilized F(ab")2 or Fab" fragment as
claimed in claim 5, wherein said insoluble carrier is selected from the group consisting of
a plate, a test tube, beads, a ball, a filter and a membrane.
7. The immobilized monoclonal antibody or immobilized F(ab")2 or Fab" fragment as
claimed in claim 5, wherein said insoluble carrier is one used for affinity purification.
8. A labeled monoclonal antibody or labeled antibody fragment which is prepared by
labeling the monoclonal antibody or F(ab")2 or Fab" fragment as claimed in claim 1 with a
labeling substance that provides a detectable signal independently or by reaction with
another substance.
9. The labeled monoclonal antibody or labeled F(ab")2 or Fab" fragment as claimed in
claim 8, wherein said labeling substance is selected from the group consisting of an
enzyme, a fluorescent material, a chemiluminescent material, biotin, avidin and a
radioisotope.
10. A kit for immunoassay to detect human CETP comprising the monoclonal
antibody or F(ab")2 or Fab" fragment, as claimed in claim 1.
11. A kit for immunoassay to detect human CETP comprising the labeled monoclonal
antibody or labeled F(ab")2 or Fab" as claimed in claim 8.
12. A kit for separation or purification of human CETP comprising the immobilized
monoclonal antibody or immobilized F(ab")2 or Fab" fragment as claimed in claim 7.

13. A pharmaceutical composition comprising the monoclonal antibody or F(ab")2 or
Fab" fragment as claimed in claim 1, and a pharmaceutically acceptable carrier for
prevention and/or treatment of hyperlipidemia.
14. A composition comprising the chimeric monoclonal antibody or F(ab)2 or Fab"
fragment as claimed in claim 3, and a pharmaceutically acceptable carrier.
15. A composition comprising the humanized monoclonal antibody or F(ab")2 or Fab"
fragment as claimed in claim 4, and a pharmaceutically acceptable carrier.
Monoclonal antibodies which has binding specificity to the human CETP (CETP
inhibition activity) available as reagents for the human CETP purification or
determination, and Pharmaceuticals of prevention and/or treatment for hyperlipidemia or
arteriosclerosis are provided. Furthermore, the purification or the determination methods
of the human CETP by using the monoclonal antibody is also provided.

Documents:

650-CAL-2000-(13-01-2012)-FORM-27.pdf

650-CAL-2000-CORRESPONDENCE 1.1.pdf

650-CAL-2000-CORRESPONDENCE.pdf

650-CAL-2000-FORM 27-1.1.pdf

650-CAL-2000-FORM 27.pdf

650-cal-2000-granted-abstract.pdf

650-cal-2000-granted-claims.pdf

650-cal-2000-granted-correspondence.pdf

650-cal-2000-granted-description (complete).pdf

650-cal-2000-granted-drawings.pdf

650-cal-2000-granted-examination report.pdf

650-cal-2000-granted-form 1.pdf

650-cal-2000-granted-form 18.pdf

650-cal-2000-granted-form 2.pdf

650-cal-2000-granted-form 3.pdf

650-cal-2000-granted-form 5.pdf

650-cal-2000-granted-letter patent.pdf

650-cal-2000-granted-pa.pdf

650-cal-2000-granted-priority document.pdf

650-cal-2000-granted-reply to examination report.pdf

650-cal-2000-granted-specification.pdf

650-cal-2000-granted-translated copy of priority document.pdf


Patent Number 214665
Indian Patent Application Number 650/CAL/2000
PG Journal Number 07/2008
Publication Date 15-Feb-2008
Grant Date 15-Feb-2008
Date of Filing 22-Nov-2000
Name of Patentee JAPAN TOBACCO INC.
Applicant Address 2-1, TORANOMON 2-CHOME, MINTO-KU, TOKYO 105
Inventors:
# Inventor's Name Inventor's Address
1 KAMADA MASAFUMI C/O. PHARMACEUTICAL BASIC RESEARCH LABORATORIES OF JAPAN TOBACCO INC, 13-2 FUKUURA 1-CHOME, KANAZAWAKU YOKOHAMA-SHI KANAGAWA 236
2 OKAMOTO HIROSHI C/O. CENTRAL PHARMACEUTICAL RESEARCH INSTITUTE OF JAPAN TOBACCO INC 1-1 MURASAKI-CHO TAKATSUKI-SHI OSAKA 569
3 TAMATANI TAKUYA C/O. PHARMACEUTICAL BASIC RESEARCH LABORATORIES OF JAPAN TOBACCO INC, 13-2 FUKUURA 1-CHOME KANAZAWA-KU YOKOHAMA-SHI KANAGWA 236
PCT International Classification Number C07K 16/00
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 134836/1995 1995-05-02 Japan