WO2013015367A1 - 上皮性卵巣癌マーカー検出用抗体及び上皮性卵巣癌判定方法 - Google Patents
上皮性卵巣癌マーカー検出用抗体及び上皮性卵巣癌判定方法 Download PDFInfo
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- WO2013015367A1 WO2013015367A1 PCT/JP2012/068990 JP2012068990W WO2013015367A1 WO 2013015367 A1 WO2013015367 A1 WO 2013015367A1 JP 2012068990 W JP2012068990 W JP 2012068990W WO 2013015367 A1 WO2013015367 A1 WO 2013015367A1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/48—Biological material, e.g. blood, urine; Haemocytometers
- G01N33/50—Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing
- G01N33/53—Immunoassay; Biospecific binding assay; Materials therefor
- G01N33/574—Immunoassay; Biospecific binding assay; Materials therefor for cancer
- G01N33/57407—Specifically defined cancers
- G01N33/57449—Specifically defined cancers of ovaries
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07K—PEPTIDES
- C07K16/00—Immunoglobulins [IGs], e.g. monoclonal or polyclonal antibodies
- C07K16/40—Immunoglobulins [IGs], e.g. monoclonal or polyclonal antibodies against enzymes
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07K—PEPTIDES
- C07K2317/00—Immunoglobulins specific features
- C07K2317/30—Immunoglobulins specific features characterized by aspects of specificity or valency
- C07K2317/33—Crossreactivity, e.g. for species or epitope, or lack of said crossreactivity
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07K—PEPTIDES
- C07K2317/00—Immunoglobulins specific features
- C07K2317/30—Immunoglobulins specific features characterized by aspects of specificity or valency
- C07K2317/34—Identification of a linear epitope shorter than 20 amino acid residues or of a conformational epitope defined by amino acid residues
Definitions
- the present invention relates to an anti- ⁇ 1,6-N-acetylglucosaminyltransferase 5B antibody for detecting an epithelial ovarian cancer marker, a hybridoma producing the antibody, and an epithelial ovarian cancer determination method using the antibody.
- Ovarian cancer is a gynecological cancer with a lower incidence than breast cancer and uterine cancer, but in recent years both incidence and mortality have been increasing.
- ovarian cancer has few subjective symptoms in the early stages of its onset, so symptoms often have already progressed at the time of discovery.Therefore, the prognosis is poor and mortality is the highest among gynecological cancers. It is a high disease.
- Ovarian cancers are known to be surface epithelial / stromal tumors (hereinafter referred to as “epithelial ovarian cancer”) arising from ovarian surface epithelial cells and germ cell tumors arising from embryonic cells, depending on the site of onset. Yes. Of these, epithelial ovarian cancer accounts for about 90% of all ovarian cancers, especially in middle-aged and older people after their 40s. Therefore, it is important to detect epithelial ovarian cancer at an early stage in the treatment of the disease.
- the ovary is an organ that is not in contact with the outside world, it cannot be examined with an endoscope or cells can be collected without performing laparotomy or perforation like the uterus.
- epithelial ovarian cancer is generally difficult to detect by palpation only after symptoms progress and the ovary is enlarged. Therefore, epithelial ovarian cancer is often overlooked by normal examination and diagnosis methods. Echo examination, MRI, CT, etc. are relatively effective for early detection of epithelial ovarian cancer, but the examination itself is large and the examination cost is high, and the accuracy of benign and malignant diagnosis is not necessarily high. There is also a problem.
- a tumor marker is a substance produced by cancer cells, or a substance produced by surrounding cells in response to cancer cells, and its abundance in body fluids reflects the presence or absence of a tumor and its prognosis. It can be a discriminator for determination and treatment guideline determination.
- inspection from body fluid is possible, there are advantages such as relatively low invasiveness, simple inspection, and low cost.
- tumor markers for epithelial ovarian cancer tumor markers composed of proteins such as CA125, CA602, CA130, CA72-4, CA546, CA19-9, and STN are known so far (Non-Patent Documents 1 to 4). 6).
- the expression level of the tumor marker in serum in normal subjects and epithelial ovarian cancer patients is usually measured, and the presence or absence of cancer is determined based on the difference in the amount.
- ovarian cancer such as CA72-4, CA19-9 and STN. It includes specificity issues such as being positive for organ cancer.
- epithelial ovarian cancer is further classified into serous, clear cell, mucous, and endometrioid by tissue type, but because the reactivity of the marker varies depending on the tissue type, it does not necessarily reflect the progression of cancer. The problem of not doing is seen.
- ovarian cancer markers such as CA125, CA602, and CA546 have a low positive rate in mucinous ovarian cancer and have a problem that the tissue type is difficult to detect even at an advanced stage.
- Patent Document 1 discloses that a cancer-related human-derived galactose transferase (GAT) is used as a tumor marker, a monoclonal antibody used for diagnosis of cancer including ovarian cancer, a hybridoma producing the same, and a cancer in a specimen using the same.
- a method for measuring related human galactose transferase has been disclosed.
- Patent Document 2 discloses that a glycosyltransferase, ⁇ 1,3-galactosyltransferase 5, ⁇ 1,3-galactosyltransferase 4, and N-acetylglucosamine 6-O-sulfotransferase 2 are used as tumor markers.
- a method for early detection of family cancer is disclosed.
- the glycosyltransferase used as a tumor marker in Patent Documents 1 and 2 is an enzyme that synthesizes a sugar chain that binds to a glycoprotein, glycolipid, proteoglycan or the like, and is usually a Golgi as a membrane protein localized in the Golgi apparatus. It is fixed to the body membrane. Therefore, it is not secreted extracellularly and is therefore rarely detected in body fluids of healthy individuals.
- glycosyltransferase is abnormally cleaved and released extracellularly as the expression level of certain proteases increases. As a result, a significant amount of glycosyltransferase fragments are detected in the body fluid.
- Patent Document 1 The glycosyltransferase and ⁇ 1,4-galactosyltransferase in Patent Document 1 are extremely expressed in glycosyltransferases and have a large amount of secretion outside the cell. Therefore, even healthy individuals show a blood concentration of about 200 ng / mL, and benign disease cannot be distinguished from cancer only by enzyme activity. Therefore, Patent Document 1 focuses on the presence of the abnormally cleaved glycosyltransferase fragment in ovarian cancer cell culture supernatant and ovarian cancer patient ascites, and uses an antibody that recognizes only this fragment. We are trying to build a measurement system with high ovarian cancer specificity.
- Non-patent Document 7 GAT is currently used mainly as a monitor for recurrence of ovarian cancer, It is rarely used as a marker for early detection.
- Patent Document 2 detection of a protein as a marker candidate from the blood of a gynecological cancer patient based on a report that expression of various proteins including glycosyltransferase is generally increased or decreased in cancer tissues. As a result, it was disclosed that the usefulness of measuring two types of glycosyltransferases was found. However, in this case, the expression or synthesis product of these glycosyltransferases has been reported to be associated with gastrointestinal cancer rather than gynecological cancer. Although expression in ovarian cancer cell lines was subsequently confirmed (Non-patent Document 8), there is no report on comparative study of expression levels in ovarian cancer or other gynecological cancers and gastrointestinal cancers.
- Patent Documents 1 and 2 focus on only detection from the body fluid of ovarian cancer patients with little consideration of the expression of glycosyltransferase in ovarian cancer, and have a glycosyltransferase fragment that happens to be measured. It is disclosed as an ovarian cancer marker. For this reason, it is considered that there is a problem in specificity as an ovarian cancer marker.
- An object of the present invention is to provide an antibody or a fragment thereof that specifically recognizes a tumor marker highly specific to epithelial ovarian cancer and can be detected quantitatively and / or qualitatively.
- the present invention provides a simple comparison of whether or not a subject suffers from epithelial ovarian cancer by quantitatively and / or qualitatively detecting an epithelial ovarian cancer marker using the antibody or fragment thereof.
- the present invention provides a method of determining with a low invasiveness and a high accuracy rate.
- glycosyltransferase ⁇ 1,6, -N-acetylglucosaminyltransferase 5B (hereinafter, this enzyme is often abbreviated as “MGAT5B”) is healthy. It was found to be more abundant in the samples of patients with epithelial ovarian cancer compared with the elderly.
- This invention is based on the said knowledge, Comprising: The following are provided. (1) An antibody for detecting an epithelial ovarian cancer marker that recognizes a part of a polypeptide consisting of the amino acid sequence represented by SEQ ID NO: 1 as an epitope. (2) The antibody according to (1), which is a monoclonal antibody. (3) The antibody according to (2), which is produced by a hybridoma whose international receipt number is FERM ABP-11496, FERM ABP-11497, FERM ABP-11498 or FERM ABP-11499.
- Anti-MGAT5B group for detecting an epithelial ovarian cancer marker comprising at least one corresponding light chain complementary chain determining region and heavy chain complementary chain determining region in the antibody according to any one of (1) to (3) Replacement antibody.
- the hybridoma according to (6), wherein the international receipt number is FERM ABP-11497.
- the hybridoma according to (6), wherein the international receipt number is FERM ABP-11498.
- An epithelial ovary that quantitatively and / or qualitatively detects an MGAT5B polypeptide fragment present in a sample derived from a subject and determines whether or not the subject has epithelial ovarian cancer based on the detection result Cancer determination method. (12) If the quantitative value of the MGAT5B polypeptide fragment in the quantitative detection result of the MGAT5B polypeptide fragment is not less than a predetermined value, the subject is determined to have a high possibility of having epithelial ovarian cancer. (11) The method for determining epithelial ovarian cancer according to (11).
- the MGAT5B polypeptide fragment is at least one selected from the group consisting of the antibody according to any one of (1) to (3), the recombinant antibody according to (4), and the antibody fragment according to (5).
- the antibody and / or fragment thereof of the present invention can specifically recognize and detect a glycosyltransferase MGAT5B polypeptide fragment that is an epithelial ovarian cancer marker.
- an anti-MGAT5B monoclonal antibody capable of specifically recognizing and detecting glycosyltransferase MGAT5B, which is an epithelial ovarian cancer marker, can be stably supplied.
- epithelial ovarian cancer can be easily detected with a relatively low invasiveness and a high accuracy rate. Thereby, it becomes possible to determine at an early stage whether or not the subject suffers from epithelial ovarian cancer.
- Lane 1 is the FLAG-MGAT5B polypeptide fragment
- Lane 2 is the MGAT5B polypeptide fragment obtained by cleaving and removing the FLAG tag by enzyme treatment
- Lane 3 is the serum of a healthy person from which immunoglobulin and albumin have been removed
- Lane 4 is The serum of untreated healthy persons is shown.
- lane 4 is a sample in which FLAG-MGAT5B polypeptide fragment mixed with serum of healthy subject is immunoprecipitated in GT131-12 antibody, or lane 5 is in healthy subject
- lane 6 shows a FLAG-MGAT5B polypeptide fragment mixed with serum of a healthy person who was not immunoprecipitated. The immunostaining of an ovarian cancer cell line using an anti-MGAT5B antibody is shown.
- a is a stained view of immunostaining of epithelial ovarian cancer cell line RMUG-S using GT131-2 antibody, b using GT131-18 antibody, and c using MAb8628 antibody which is a positive control.
- the signal intensity with respect to the concentration standard in the examination of antibody combinations for sandwich ELISA is shown.
- the standard curve of the MGAT5B polypeptide fragment obtained from the value obtained by measuring the concentration standard using the sandwich CLEIA method using GT131-7 antibody and GT131-12 antibody is shown.
- collected from the test subject using the sandwich CLEIA method using GT131-7 antibody and GT131-12 antibody is shown.
- the correlation between the measured value of MGAT5B polypeptide fragment and the measured value of existing ovarian cancer marker CA125 (a) or GAT (b) in the peritoneal lavage fluid collected from patients with epithelial ovarian cancer is shown.
- the correlation with the CA125 measurement value and the GAT measurement value of the peritoneal lavage fluid collected from a patient with epithelial ovarian cancer is shown.
- the first embodiment of the present invention is an antibody for detecting an epithelial ovarian cancer marker.
- the antibody of the present invention is an antibody used for detecting an epithelial ovarian cancer marker, characterized by recognizing and specifically binding to an epitope contained in the epithelial ovarian cancer marker.
- epithelial ovarian cancer marker is a biological marker for detecting epithelial ovarian cancer, which is an index indicating that the subject is suffering from epithelial ovarian cancer. It is a substance in the body.
- the epithelial ovarian cancer marker in the present invention is a ⁇ 1,6-N-acetylglucosaminyltransferase 5B polypeptide fragment.
- MGAT5B “ ⁇ 1,6-N-acetylglucosaminyltransferase 5B (MGAT5B)” is a kind of N-linked sugar chain synthase that is localized as a membrane protein mainly in the Golgi membrane. It is known to transfer acetylglucosamine (Kaneko M. et al., 2003, FEBS Letters, 554: 515-519). MGAT5B contains one transmembrane domain on the N-terminal side, and has a C-terminal region that is an enzyme active region inside the Golgi apparatus.
- MGAT5B in the present invention is a human-derived wild-type MGAT5B consisting of 790 amino acids registered in GenBank Accession No. NP_653278, specifically, a polypeptide consisting of the amino acid sequence shown in SEQ ID NO: 2.
- MGAT5B includes wild-type MGAT5B and its natural variants.
- the “natural variant” of MGAT5B is a naturally occurring variant, and is 1 to 10, preferably 1 to 5, in the amino acid sequence constituting wild-type MGAT5B shown in SEQ ID NO: 2.
- About 90% or more of the amino acid sequence shown in SEQ ID NO: 2, or preferably a variant comprising deletion, substitution, addition or insertion of 1 to 4, 1 to 3, or 1 or 2 amino acids Preferably refers to a polypeptide exhibiting about 95% or more, more preferably about 98% or more identity.
- identity means that the amino acid sequence shown in SEQ ID NO: 2 and the target amino acid sequence were aligned (aligned) by introducing gaps as necessary so that both amino acid sequences had the highest degree of coincidence.
- the ratio (%) of the number of identical amino acid residues of the subject amino acid sequence to the total number of amino acid residues of the amino acid sequence shown in SEQ ID NO: 2 when the number of gaps is included.
- This identity can be determined using a protein search system using BLASTP or FASTA.
- Specific examples of natural mutants include mutants based on polymorphisms such as SNP (single nucleotide polymorphism) and splice mutants.
- the natural mutant of MGAT5B does not necessarily have the same enzyme activity as wild-type MGAT5B. In the case of glycosyltransferases, it has been reported that there are natural mutants that lose their activity significantly by substitution of only one amino acid (Nishihara S. et al., 1993, Biochem. Biophys. Res. Commun. 196: 624-631).
- MGAT5B polypeptide fragment refers to a polypeptide fragment derived from MGAT5B released extracellularly as a result of abnormal cleavage from the Golgi membrane by protease in epithelial ovarian cancer cells. And a polypeptide that can function as an epithelial ovarian cancer marker.
- a polypeptide comprising all or part of the C-terminal region located inside the Golgi apparatus excluding the N-terminal region containing the transmembrane domain, such as human MGAT5B shown in SEQ ID NO: 2
- the polypeptide consisting of all or part of the amino acid sequence after the glycine residue at position 51 (starting methionine is position 1) shown in SEQ ID NO: 1 and fragments derived from the polypeptide are applicable.
- the “antibody for detecting epithelial ovarian cancer” of the present invention is an antibody derived using the MGAT5B polypeptide fragment, which is the epithelial ovarian cancer marker, as an antigen. Therefore, in the present specification, “antibody for detecting epithelial ovarian cancer marker” is often referred to as “anti-MGAT5B antibody”.
- the anti-MGAT5B antibody recognizes and binds to a part of the epithelial ovarian cancer marker as an epitope, and can specifically detect the epithelial ovarian cancer marker. Specifically, a part of the amino acid consisting of the amino acid sequence shown in SEQ ID NO: 1 is used as an epitope.
- “part” refers to one or a plurality of regions consisting of 5 to 15, preferably 5 to 10, more preferably 6 to 10 consecutive amino acids.
- the anti-MGAT5B antibody of the present invention may be either a polyclonal antibody or a monoclonal antibody. Monoclonal antibodies are desirable to enable more specific detection. Specific examples of anti-MGAT5B monoclonal antibodies include, for example, anti-MGAT5B antibodies produced by hybridomas whose international receipt numbers are FERM ABP-11496, FERM ABP-11497, FERM ABP-11498, and FERM ABP-11499. These antibodies will be described in detail in the section “(3) Production of anti-MGAT5B monoclonal antibody”.
- the anti-MGAT5B antibody of the present invention can be modified.
- modification includes functional modifications necessary for antigen-specific binding activation such as glycosylation, or labels necessary for antibody detection.
- Antibody labels include, for example, fluorescent dyes (FITC, rhodamine, Texas red, Cy3, Cy5), fluorescent proteins (eg, PE, APC, GFP), enzymes (eg, horseradish peroxidase, alkaline phosphatase, glucose oxidase), or Examples include labeling with biotin or (strept) avidin.
- the modification on the anti-MGAT5B antibody can be altered.
- glycosylation of the anti-MGAT5B antibody may be modified to adjust the affinity of the anti-MGAT5B antibody for the epithelial ovarian cancer marker that is the target antigen.
- substitution is introduced into the amino acid residue constituting the glycosylation site to remove the glycosylation site, and thereby the site. Modifications that lose the glycosylation of are included.
- the anti-MGAT5B antibody of the present invention preferably has a high affinity with a dissociation constant with an epithelial ovarian cancer marker of 10 ⁇ 8 M or less, preferably 10 ⁇ 9 M or less, more preferably 10 ⁇ 10 M or less.
- the dissociation constant can be measured using a technique known in the art. For example, it may be measured using a speed evaluation kit software by a BIAcore system (GE Healthcare).
- the anti-MGAT5B polyclonal antibody or anti-MGAT5B monoclonal antibody of the present invention can be obtained by the production method described later. Further, if it is an anti-MGAT5B monoclonal antibody, it may be prepared by a chemical synthesis method or by using a recombinant DNA technique based on its amino acid sequence. Furthermore, anti-MGAT5B monoclonal antibodies can also be obtained from hybridomas that produce the antibodies.
- the species of the anti-MGAT5B antibody of the present invention is not particularly limited. It can be derived from any animal source including birds and mammals. Examples include mice, rats, guinea pigs, rabbits, goats, donkeys, sheep, camels, horses, chickens, and humans.
- the globulin type of the anti-MGAT5B antibody of the present invention is not particularly limited, and may be any of IgG, IgM, IgA, IgE, IgD, and IgY, with IgG and IgM being preferred.
- anti-MGAT5B antibody of the present invention that is, an anti-MGAT5B polyclonal antibody and an anti-MGAT5B monoclonal antibody, or a hybridoma producing an anti-MGAT5B monoclonal antibody can be produced by the method described below. However, it is not limited to the following method, It can also produce using any other method known in the said field
- the epithelial ovarian cancer marker that can be used as an immunogen in the present invention is, for example, all or a part of a human MGAT5B polypeptide fragment having the amino acid sequence shown in SEQ ID NO: 1, or all or a polypeptide fragment of a variant thereof. It is a part.
- the MGAT5B polypeptide fragment as an immunogen can be prepared using, for example, a chemical synthesis method or a DNA recombination technique.
- a suitable method for use as an immunogen by a technique known in the art, for example, a solid phase peptide synthesis method, etc.
- the MGAT5B polypeptide fragment may be chemically synthesized.
- MGAT5B polypeptide fragments can be obtained by incorporating and expressing cDNA encoding MGAT5B (MGAT5B cDNA) in an appropriate expression system.
- MGAT5B cDNA cDNA encoding MGAT5B
- MGAT5B cDNA can be prepared by a known technique, for example, a cDNA cloning method. Specifically, first, a human cDNA library is prepared. A human cDNA library is prepared by extracting total RNA from human fibroblasts (neuuroblastoma cell line SK-N-SH) expressing the MGAT5B gene and the like based on a conventional method, and then treating the poly A with an oligo dT cellulose column. (+) RNA can be collected and prepared by RT-PCR using it as a template. In addition, a commercially available human cDNA library may be used.
- a human cDNA library may be used.
- the target MGAT5B cDNA clone is isolated from the human cDNA library. Specifically, it may be isolated by a known screening method such as a hybridization screening method, an expression screening method, an antibody screening method, etc., using primers and / or probes appropriately designed based on the MGAT5B gene sequence.
- the MGAT5B gene sequence is registered in the GenBank database under accession number NM-_144677.
- an MGAT5B gene region encoding the amino acid sequence shown in SEQ ID NO: 1 is included in the amplified fragment.
- a restriction site suitable for cloning after isolation or a tag sequence for protein purification may be introduced on the 5 'end side of the forward / reverse primer.
- a tag sequence for protein purification FLAG, HA, His, myc, GFP, etc.
- the MGAT5B cDNA clone may be amplified by a nucleic acid amplification method such as a PCR method, if necessary.
- the obtained MGAT5B cDNA clone is incorporated into an expression vector.
- Specific examples include expression vectors using plasmids or viruses.
- the expression vector may be an expression vector for E.
- Bacillus subtilis-derived expression vector for example, pUB110 system, pTP5 system
- Yeast-derived expression vectors eg, YEp13, YEp24, YCp50
- insect cell expression vectors eg, baculovirus
- animal cell expression vectors eg, pA1-11, pXT1, pRc / CMV, pRc / RSV, pcDNAI / Neo
- Expression vectors usually can contain regulatory elements such as promoters, terminators, enhancers, polyadenylation signals, origins of replication, selectable markers, and the like.
- regulatory elements such as promoters, terminators, enhancers, polyadenylation signals, origins of replication, selectable markers, and the like.
- those having a sequence encoding a secretory signal sequence on the 5 ′ end side of the insertion site may be used.
- the mature polypeptide expressed extracellularly can be secreted.
- Such expression vectors and other expression systems are available from various manufacturers (Takara Bio, Daiichi Kagaku, Agilent Technologies, Merck, Qiagen, Promega, Roche Diagnostics, Life Technologies, GE Healthcare, etc.) Since useful products are commercially available, they may be used.
- the purified MGAT5B cDNA may be cleaved with an appropriate restriction enzyme, inserted into a corresponding restriction site on the expression vector side, and ligated with the vector.
- the MGAT5B cDNA may be subcloned using an appropriate plasmid or the like before being incorporated into an expression vector.
- the obtained MGAT5B expression system (for example, MGAT5B expression vector) is introduced into a host cell to express the target MGAT5B polypeptide fragment as an immunogen.
- the host cell to be used is not particularly limited as long as it is a host cell compatible with the expression vector used for preparation of the MGAT5B expression vector and can express MGAT5B.
- Escherichia coli is used
- Bacillus subtilis is used
- yeast is used.
- yeast for example, budding yeast: Saccharomyces cerevisiae, fission yeast: Schizosaccharomyces pombe
- insect cell expression vectors insect cells (for example, Sf cells) or animal cell expression vectors are used
- mammalian cells eg, HEK293, HeLa, COS, CHO, BHK
- a cell-free translation system can also be used.
- the method for introducing the MGAT5B expression vector into the host cell may be a known method for introducing DNA into each host cell, and is not particularly limited.
- a heat shock method, a calcium ion method, an electroporation method, and the like can be used as long as the vector is introduced into bacteria.
- these techniques are all known in the art, including Sambrook, J. et. Al., (1989) Molecular Cloning: A Laboratory Manual Second Ed., Cold Spring Harbor Laboratory Press, Cold Spring Harbor, New York. It is described in various literatures.
- the lipofectin method (PNAS (1989) Vol.86, 6077), electroporation method, calcium phosphate method (Virology (1973) Vol.52, 456- 467), DEAE-Dextran method and the like are preferably used.
- a commercially available nucleic acid introduction agent such as Lipofectamin 2000 (Life Technologies) may also be used.
- the obtained transformant for expressing MGAT5B is a microorganism such as Escherichia coli or yeast, it contains a carbon source, nitrogen source, inorganic salts, etc. that can be assimilated by the microorganism, and culture of the transformant
- a natural medium or a synthetic medium can be used.
- LB medium can be mentioned.
- the culture is usually carried out at 37 ° C. for 6 to 24 hours under aerobic conditions such as shaking culture or aeration and agitation culture. During the culture period, the pH is preferably maintained near neutrality. If necessary, an antibiotic such as ampicillin or tetracycline may be added to the medium.
- the transformant for expressing MGAT5B when it is a mammalian cell or the like, it may be cultured in a medium suitable for each cell.
- the medium may or may not contain serum, but culture in a serum-free medium is more desirable.
- the MGAT5B expression vector is, for example, a protein expression inducing vector containing a repressor gene, an operator, and the like, it is necessary to perform a predetermined treatment on the transformant to induce the expression of the MGAT5B polypeptide fragment. Since the expression induction method varies depending on the protein expression control system contained in the vector, an induction process suitable for the system may be performed.
- the most commonly used protein expression control system in a protein expression inducing vector using a bacterium as a host is a system comprising a lac repressor gene and a lac operator. This system can induce expression by IPTG (isopropyl-1-thio- ⁇ -D-Galactoside) treatment.
- IPTG isopropyl-1-thio- ⁇ -D-Galactoside
- the MGAT5B polypeptide fragment produced in the host cell is recovered from the cell or the culture supernatant.
- the produced MGAT5B polypeptide fragment accumulates in cells or cells, the cells or cells are crushed and protein is extracted.
- the culture solution can be used as it is, or the cells or cells can be removed by centrifugation or the like, and the supernatant can be used. Thereafter, the MGAT5B polypeptide fragment can be isolated and purified by using a general protein purification method.
- the MGAT5B polypeptide fragment is expressed as a fusion peptide with a labeled peptide (tag), for example, an affinity chromatography method suitable for each labeled peptide may be used.
- an affinity chromatography method suitable for each labeled peptide may be used.
- the two or more purification methods can be appropriately combined for isolation and purification.
- MGAT5B polypeptide fragment prepared by the above method retains activity as a glycosyltransferase and is soluble.
- the MGAT5B polypeptide fragment is dissolved in a buffer solution to prepare an immunogen solution.
- an adjuvant may be added if necessary for effective immunization.
- the adjuvant include Freund's complete adjuvant (FCA), Freund's incomplete adjuvant (FIA), aluminum hydroxide gel, pertussis vaccine, TiterTiMax Gold (Vaxel), GERBU adjuvant (GERBU Biotechnik), etc. Can be used as a mixture.
- the prepared immunogen solution is administered to a mammal and immunized.
- the animal used for immunization is not particularly limited.
- non-human mammals more specifically mice, rats, hamsters, guinea pigs, rabbits, goats, donkeys, sheep, camels, horses, and the like can be used.
- a method using a mouse is taken as an example and will be specifically described below.
- Examples of the method of administering the immunogen solution include subcutaneous injection using FIA or FCA, intraperitoneal injection using FIA, or intravenous injection using physiological saline, but are not limited thereto. Administration may be by intradermal or intramuscular injection.
- the dose of the immunogen is determined appropriately according to the type of animal to be immunized, the route of administration, etc. In the case of mice, it is usually administered at about 50 to 200 ⁇ g per 4 to 10 week-old individual. do it.
- the interval between immunizations is not particularly limited, but is from several days to several weeks, preferably from 1 to 4 weeks.
- booster immunization is preferably performed, and the frequency is 2 to 6 times, preferably 3 to 4 times.
- blood is preferably collected from the fundus etc. of the immunized mouse, and the antibody titer in the serum is measured by ELISA or the like. If the antibody titer rises sufficiently, the immunogen solution may be injected intravenously or intraperitoneally to obtain the final immunization. It is preferable not to use an adjuvant in the final immunization.
- blood is collected from the immunized mouse and treated with serum according to a known method (Antibodies: A Laboratory Manual Cold Spring Harbor Laboratory, 1988). MGAT5B polyclonal antibody can be obtained.
- the production of anti-MGAT5B monoclonal antibody can be prepared by the method of Keller & Milstein (Nature 256: 495-497 (1975)).
- a hybridoma is prepared by cell fusion between an antibody-producing cell obtained from the immunized animal and a myeloma cell, and a clone producing an anti-MGAT5B monoclonal antibody is selected from the obtained hybridoma.
- a clone producing an anti-MGAT5B monoclonal antibody is selected from the obtained hybridoma.
- antibody-producing cells are collected from the immunized mouse.
- the collection is preferably 2 to 5 days after the last immunization.
- Examples of antibody-producing cells include spleen cells, lymph node cells, and peripheral blood cells, and spleen cells or local lymph node cells are preferred.
- a method for collecting antibody-producing cells from mice may be performed according to a technique known in the art.
- a hybridoma producing an anti-MGAT5B monoclonal antibody can be produced by performing cell fusion between the antibody-producing cells and myeloma (myeloma) cells.
- the myeloma cell used for cell fusion is not particularly limited as long as it is a generally available cell line derived from a mouse and can be proliferated in vitro. In order to select, those having drug selectivity and having the property of not being able to survive in a selective medium in an unfused state but capable of growing only in a state fused with antibody-producing cells are preferable.
- Myeloma cells are known in various known cell lines such as P3 (P3x63Ag8.653) (Kearney JF et al., 1979, J. Immunol., 123: 1548-1550), P3x63Ag8U.1 (Yelton DE et al , 1978, Curr. Top. Microbiol. Immunol., 81: 1-7), NS-1 (Kohler G. et al., 1976, Eur. J. Immunol., 6: 511-519), MPC-11 (Margulies DH et al., 1976, Cell, 8: 405-415), SP2 / 0 (Shulman M.
- the selection medium includes, for example, HAT medium (RPMI1640 medium with 100 units / mL penicillin, 100 ⁇ g / mL streptomycin and 10% fetal bovine serum (FBS), 10 ⁇ 4 M hypoxanthine, 1.5 ⁇ 10 ⁇ 5 M thymidine and Medium containing 4 ⁇ 10 ⁇ 7 M aminopterin).
- HAT medium RPMI1640 medium with 100 units / mL penicillin, 100 ⁇ g / mL streptomycin and 10% fetal bovine serum (FBS), 10 ⁇ 4 M hypoxanthine, 1.5 ⁇ 10 ⁇ 5 M thymidine and Medium containing 4 ⁇ 10 ⁇ 7 M aminopterin).
- animal cell culture media such as MEM, DMEM, and RPMI1640 media, commercially available cloning
- myeloma cells and antibody-producing cells are mixed at a mixing ratio of 1: 1 to 1:10 and 30 in the presence of a cell fusion promoter.
- Contact may be performed at ⁇ 37 ° C. for 1 to 15 minutes.
- polyethylene glycol having an average molecular weight of 1,500 to 4,000 Da (hereinafter referred to as “PEG”) or the like can be used at a concentration of about 10 to 80%.
- a fusion promoter such as polyvinyl alcohol or Sendai virus or a fusion virus can also be used.
- PEG having an average molecular weight of 1,500 Da is preferably used.
- an auxiliary such as dimethyl sulfoxide may be used in combination as necessary.
- antibody-producing cells and myeloma cells can be fused using a commercially available cell fusion device utilizing electrical stimulation (for example, electroporation) (Nature, 1977, Vol. 266, 550-552).
- the cells are washed with a medium (for example, RPMI1640 medium) used for fusion of myeloma cells, and then a cell suspension is prepared. Subsequently, the cell suspension is prepared, for example, with FBS-containing RPMI1640 medium. After appropriately diluting, etc., about 1 ⁇ 10 4 cells / well are placed on a 96-well plate, a selective medium is added to each well, and thereafter, the selective medium is appropriately exchanged and cultured.
- the culture temperature is 20 to 40 ° C, preferably about 37 ° C.
- the myeloma cells are of HGPRT deficient strain or thymidine kinase (TK) deficient strain
- antibody-producing cells and myeloma cells can be obtained by using a selective medium (HAT medium) containing hypoxanthine, aminopterin and thymidine. Since only the hybridoma can be selectively grown and propagated, cells that grow from about 10 days after the start of culture in the selective medium can be selected as the hybridoma.
- HAT medium containing hypoxanthine, aminopterin and thymidine. Since only the hybridoma can be selectively grown and propagated, cells that grow from about 10 days after the start of culture in the selective medium can be selected as the hybridoma.
- Hybridoma screening is performed, for example, by collecting a part of the culture supernatant contained in a well in which the hybridoma is cultured, and using an enzyme immunoassay method (ELISA method, etc.) using as an index the binding activity to the MGAT5B polypeptide fragment used as an immunogen. It can be screened by radioimmunoassay (RIA) or the like. Further, in order to obtain a hybridoma that stably produces a monoclonal antibody, the antibody-producing hybridoma is cloned.
- the cloning method is not particularly limited, and may be performed by a usual method such as a limiting dilution method or a fluorescence excitation cell sorter method.
- a cross-reactivity test may be performed. That is, the binding activity to other proteins including other glycosyltransferases and the like is verified, and only hybridomas that produce antibodies exhibiting acceptable cross-reactivity are selected. Acceptable cross-reactivity refers to the nonspecific binding activity of a monoclonal antibody that is negligible in the intended application.
- anti-MGAT5B monoclonal antibody-producing hybridomas selected by the above screening method include, for example, GT131-2 (Domestic accession number: FERM P-22097; International receipt number: FERM ABP-11496), GT131-7 (Domestic accession number) : FERM P-22098; International receipt number: FERM ABP-11497), GT131-12 (Domestic accession number: FERM P-22099; International receipt number: FERM ABP-11498) and GT131-18 (Domestic accession number: FERM P- 22100; international receipt number: FERM ABP-11499).
- hybridoma cell lines can be suitably cultured at 37 ° C. using a medium in which 10% FBS is added to RPMI1640.
- Anti-MGAT5B monoclonal antibody can be recovered by conventional techniques. For example, a normal cell culture method or ascites formation method can be employed as a method for recovering from the established hybridoma.
- the anti-MGAT5B monoclonal antibody-producing hybridoma is cultured in an animal cell culture medium such as RPMI1640 medium, MEM medium, or serum-free medium containing 10% FBS, for example, at 37 ° C. and 5% CO 2 concentration for 2 to 10 days. Culturing and obtaining the antibody from the culture supernatant.
- GT131-2, GT131-7, GT131-12, and GT131-18 which are given as specific examples of the above-mentioned anti-MGAT5B monoclonal antibody-producing hybridoma, are also referred to as “GT131-2 antibody”, “GT131- 7 antibody ",” GT131-12 antibody “and” GT131-18 antibody "can be obtained.
- the antibody When the antibody needs to be purified, it may be purified using a known method as appropriate. For example, it can be purified using ion exchange chromatography, affinity chromatography using protein A or protein G, gel chromatography, ammonium sulfate salting out, and the like.
- Reagent for detecting epithelial ovarian cancer The anti-MGAT5B antibody of the present invention, the recombinant antibody for detecting epithelial ovarian cancer marker described below and / or the antibody fragment for detecting epithelial ovarian cancer marker specifically react with the epithelial ovarian cancer marker. It can be used as an active ingredient in an epithelial ovarian cancer detection reagent. By using this detection reagent and detecting an epithelial ovarian cancer marker contained in a sample collected from the subject, it is also possible to determine the morbidity of the subject in epithelial ovarian cancer.
- the detection reagent of the present invention can be used by any means using an immunological technique.
- epithelial ovarian cancer can be detected easily and quickly by using it in combination with a reagent (CLEIA) for a fully automatic immunoassay device.
- CLIA reagent
- the epithelial ovarian cancer detection reagent can also be used for staining of epithelial ovarian cancer tissue.
- the presence or absence of epithelial ovarian cancer can be determined by detecting the presence or absence of an epithelial ovarian cancer marker by immunostaining in tissues obtained by laparotomy or needle stick.
- the presence or absence of epithelial ovarian cancer can be determined by detecting the presence or absence of an epithelial ovarian cancer marker by a method such as Western blotting using the extracted tissue extract.
- the anti-MGAT5B antibody of the present invention can specifically recognize and bind to the Golgi region of glycosyltransferase MGAT5B, which is an epithelial ovarian cancer marker. Therefore, by using the anti-MGAT5B antibody of the present invention, an epithelial ovarian cancer marker can be efficiently detected from a sample of a subject.
- the second embodiment of the present invention is a recombinant antibody for detecting an epithelial ovarian cancer marker.
- the recombinant antibody of the present invention comprises at least one pair of a corresponding light chain complementary chain determining region (CDR) and heavy chain CDR in the antibody for detecting an epithelial ovarian cancer marker described in the first embodiment.
- CDR light chain complementary chain determining region
- recombinant antibody for detecting epithelial ovarian cancer marker is often referred to as “anti-MGAT5B recombinant antibody”.
- the “recombinant antibody” refers to, for example, a chimeric antibody, a humanized antibody, and a synthetic antibody.
- a “chimeric antibody” is an antibody in which the constant region of the light and heavy chains (C region: Constant region) is replaced with the C region of the light and heavy chains of another antibody.
- C region Constant region
- a mouse anti-human MGAT5B monoclonal antibody, GT131-2 antibody, GT131-7 antibody, GT131-12 antibody or GT131-18 antibody, in which the C region is replaced with the C region of an appropriate human antibody corresponds. That is, the variable region (V region: Variable region) including CDR is derived from GT131-2 antibody, GT131-7 antibody, GT131-12 antibody or GT131-18 antibody, and C region is derived from a human antibody.
- “Humanized antibody” is also referred to as a reshaped human antibody, and is a mosaic antibody in which only the CDR in the V region of a non-human mammal, for example, an anti-human MGAT5B mouse antibody, is replaced with the CDR of an appropriate human antibody. It is.
- a DNA sequence encoding each CDR region (CDR1 to CDR ⁇ 3) derived from GT131-2 antibody, GT131-7 antibody, GT131-12 antibody or GT131-18 antibody encodes each corresponding CDR derived from a human antibody
- a recombinant antibody that mimics the properties of that particular antibody can be obtained.
- a general genetic recombination technique for preparing a humanized antibody is also known (European Patent Application Publication No. EP 125023).
- oligos prepared by having a DNA sequence designed to link the CDR of a mouse antibody and the framework region (FR) of a human antibody with a portion overlapping both terminal regions of CDR and FR Examples include a method of synthesis by PCR using nucleotides as primers.
- “Synthetic antibody” refers to an antibody synthesized by using a chemical method or a recombinant DNA method. For example, a quantity obtained by artificially linking one or more light chain V regions (VL) and one or more heavy chain V regions (VH) of a specific antibody via a linker peptide having an appropriate length and sequence Body polypeptide molecules, or multimeric polypeptides thereof. Specific examples of such polypeptides include single chain Fv (scFv: single chain Fragment of variable region) (Pierce Catalog and Handbook, 1994-1995, Pierce Chemical Co., Rockford, IL), diabody ), Triabody or tetrabody.
- scFv single chain Fragment of variable region
- VL and VH are usually located on separate polypeptide chains (light chain and heavy chain).
- Single-chain Fv is a synthetic antibody fragment having a structure encompassed by one polypeptide chain, in which V regions on these two polypeptide chains are connected by a flexible linker having a sufficient length. Within a single chain Fv, both V regions can self-assemble with each other to form one functional antigen binding site.
- Single-stranded Fv can be obtained by integrating and expressing a recombinant DNA encoding it in the phage genome using known techniques.
- a diabody is a molecule having a structure based on a dimeric structure of a single chain Fv (Holliger et al., 1993, Proc. Natl.
- the two variable sites within the single chain Fv cannot self-assemble, but by forming a diabody, i.e., two single chain Fv ,
- the VL of one Fv chain can be assembled with the VH of the other Fv chain to form two functional antigen binding sites (Marvin et al., 2005, Acta Pharmacol. Sin. 26: 649-658).
- a cysteine residue to the C-terminus of the single chain Fv, it becomes possible to form a disulfide bond between the two Fv chains and to form a stable diabody (Olafsen et al., 2004).
- a diabody is a bivalent antibody fragment, but each antigen-binding site need not bind to the same epitope, and each has a bispecificity that recognizes and specifically binds to a different epitope. You may do it.
- Triabodies and tetrabodies have their trimer and tetramer structures based on a single-chain Fv structure as in diabodies. These are trivalent and tetravalent antibody fragments, respectively, and may be multispecific antibodies.
- anti-MGAT5B recombinant antibody may be produced by a DNA cloning technique known in the art using the anti-MGAT5B antibody produced in the first embodiment.
- a DNA cloning technique known in the art using the anti-MGAT5B antibody produced in the first embodiment.
- the anti-MGAT5B recombinant antibody of the present invention can specifically recognize and bind to the Golgi region of glycosyltransferase MGAT5B, which is an epithelial ovarian cancer marker. . Therefore, by using the anti-MGAT5B recombinant antibody of the present invention, an epithelial ovarian cancer marker can be efficiently detected from a sample of a subject.
- the third embodiment of the present invention is an antibody fragment for detecting an epithelial ovarian cancer marker.
- the “antibody fragment” of the present invention is a partial region of the anti-MGAT5B antibody described in the first embodiment or the anti-MGAT5B recombinant antibody described in the second embodiment, and has an MGAT5B-specific recognition / binding activity possessed by the antibody.
- an antibody partial region including at least one antigen-binding site contained in the anti-MGAT5B antibody of Embodiment 1 or the anti-MGAT5B antibody of Embodiment 2 that is, a polypeptide chain having at least one pair of VL and VH Or a complex thereof.
- the anti-MGAT5B antibody of Embodiment 1 includes a number of well-characterized fragments generated by cleaving the antibody with various peptidases.
- Specific examples include Fab, F (ab ′) 2 , Fab ′ and the like.
- Fab is a fragment generated by cleaving IgG molecules at the N-terminal side of the disulfide bond at the hinge part by papain, and VH and H chain C region (heavy chain constant region: hereinafter referred to as “CH”) Among the three domains (CH1, CH2, and CH3), the polypeptide is composed of CH1 adjacent to VH and the light chain.
- F (ab ′) 2 is a dimer of Fab ′ generated by cleaving IgG molecules at the C-terminal side of the disulfide bond at the hinge part by pepsin.
- Fab ' has a structure substantially equivalent to that of Fab, although the H chain is slightly longer than Fab so as to include the hinge part.
- Fab ′ can be obtained by reducing F (ab ′) 2 under mild conditions and breaking the disulfide linkage in the hinge region. Since these antibody fragments all include an antigen binding site, they have the ability to specifically bind to an antigen (ie, MGAT5B in the present invention).
- the antibody fragment for detecting epithelial ovarian cancer marker of the present invention specifically recognizes and binds to the Golgi region of glycosyltransferase MGAT5B, which is an epithelial ovarian cancer marker. can do. Therefore, by using the antibody fragment for detecting epithelial ovarian cancer marker of the present invention, the epithelial ovarian cancer marker can be efficiently detected from the sample of the subject.
- Epithelial ovarian cancer determination method The fourth embodiment of the present invention is an epithelial ovarian cancer determination method.
- the method for determining epithelial ovarian cancer of the present invention quantitatively and / or qualitatively detects an epithelial ovarian cancer marker present in a subject-derived sample, and based on the detection result, epithelial ovarian cancer in the subject Determine the presence or absence of illness.
- the “subject” refers to a person who is subjected to a test in the method of the present invention, that is, a person who provides a sample described later. Preferred subjects are those who may be suffering from epithelial ovarian cancer or epithelial ovarian cancer patients.
- “healthy person” refers to a healthy person in a broad sense that is healthy with respect to epithelial ovarian cancer, that is, a person who is not affected with epithelial ovarian cancer. Therefore, as long as it does not suffer from epithelial ovarian cancer, it may be a person suffering from other diseases such as stomach cancer and uterine cancer. Preferably, it is a healthy person in a narrow sense who is not affected by any disease, that is, a healthy person.
- sample is collected from the subject and directly used for the method of the present invention, and corresponds to, for example, a body fluid, an abdominal cavity lavage fluid, or a tissue.
- Body fluid refers to a liquid biological sample collected directly from a subject.
- blood including serum, plasma and interstitial fluid
- lymph including serum, plasma and interstitial fluid
- cerebrospinal fluid ascites
- pleural effusion sputum
- tears nasal discharge
- tissue includes sections and extracts.
- preferred samples are blood, lymph, body fluid such as ascites, or peritoneal lavage fluid.
- Sample collection may be performed based on a known method in this field.
- blood or lymph can be obtained according to a known blood collection method.
- peripheral blood it may be collected by injection into a peripheral vein or the like.
- ascites or peritoneal lavage fluid collection by puncture suction avoiding the intestinal tract under the guide of transabdominal ultrasonic tomography, or about 100 mL of physiological saline is injected into the abdominal cavity at the time of laparotomy, and a syringe or the like is used from the Douglas fossa.
- Samples collected from the subject are pretreated by diluting or concentrating as necessary, adding a blood coagulation inhibitor such as heparin, or fixing with a fixing agent such as paraffin in the case of tissue. Can be used after. Moreover, you may use as it is, without performing such a pre-processing.
- a blood coagulation inhibitor such as heparin
- a fixing agent such as paraffin
- Specimens may be used immediately after collection, or may be used after being frozen and stored for a certain period of time and then subjected to processing such as thawing as necessary.
- a volume of 10 ⁇ L to 100 ⁇ L is usually sufficient for detection of an epithelial ovarian cancer marker.
- the epithelial ovarian cancer marker to be detected is the MGAT5B polypeptide fragment described in the first embodiment. Specifically, it is a polypeptide fragment consisting of an amino acid sequence located in the Golgi region and corresponding to the C-terminal side of MGAT5B.
- human MGAT5B corresponds to all or part of the polypeptide consisting of the amino acid sequence shown in SEQ ID NO: 1.
- Any method may be used as a method for detecting an epithelial ovarian cancer marker in a sample as long as it is a known method capable of detecting the marker that is a polypeptide.
- a detection method immunological detection method using an immunological reaction using an antibody that specifically recognizes and binds to an epithelial ovarian cancer marker is preferable.
- Anti-MGAT5B antibody (including anti-MGAT5B polyclonal antibody and anti-MGAT5B monoclonal antibody) described in Embodiment 1 above is used as an epithelial ovarian cancer marker-specific antibody (hereinafter referred to as “anti-epithelial ovarian cancer marker antibody”),
- the anti-MGAT5B recombinant antibody described in Form 2 and / or the antibody fragment described in Embodiment 3 can be used.
- Specific examples include GT131-2 antibody, GT131-7 antibody, GT131-12 antibody, or GT131-18 antibody, which are mouse anti-human MGAT5B monoclonal antibodies described in Embodiment 1.
- immunological detection methods for detecting the amount of epithelial ovarian cancer marker present in a sample derived from a subject include enzyme immunoassays (including ELISA and EIA methods), fluorescent immunoassays, and radiation.
- the epithelial ovarian cancer marker of the present invention is measured by an immunological assay using a label such as the enzyme immunoassay, fluorescence immunoassay, radioimmunoassay or luminescence immunoassay described above. It is preferable to immobilize the anti-epithelial ovarian cancer marker antibody or the like, or to immobilize the components in the sample (that is, epithelial ovarian cancer marker) and perform their immunological reaction.
- a label such as the enzyme immunoassay, fluorescence immunoassay, radioimmunoassay or luminescence immunoassay described above.
- solid phase carriers beads made of materials such as polystyrene, polycarbonate, polyvinyltoluene, polypropylene, polyethylene, polyvinyl chloride, nylon, polymethacrylate, latex, gelatin, agarose, cellulose, sepharose, glass, metal, ceramics or magnetic materials Insoluble carriers in the form of microplates, test tubes, sticks or test pieces can be used.
- Solid phase is achieved by binding the anti-epithelial ovarian cancer marker antibody or epithelial ovarian cancer marker to a solid phase carrier according to a known method such as physical adsorption, chemical binding, or a combination thereof. Can do.
- the labeling agent for labeling the anti-epithelial ovarian cancer marker antibody is peroxidase (POD), alkaline phosphatase, ⁇ -galactosidase, urease, catalase, glucose oxidase, lactate dehydrogenase, amylase or Examples include biotin (or avidin).
- POD peroxidase
- alkaline phosphatase alkaline phosphatase
- ⁇ -galactosidase urease
- catalase glucose oxidase
- lactate dehydrogenase lactate dehydrogenase
- amylase or Examples include biotin (or avidin).
- fluorescein isothiocyanate, tetramethylrhodamine isothiocyanate, substituted rhodamine isothiocyanate, dichlorotriazine isothiocyanate, Alexa, AlexaFluoro, and the like can be mentioned.
- a radioimmunoassay tritium, iodine 125, iodine 131, etc. are mentioned. Further, NADH, FMNH2, luciferase system, luminol-hydrogen peroxide-POD system, acridinium ester system or dioxetane compound system can be used for the luminescence immunoassay.
- the binding method between the labeling substance and the antibody is a known method such as glutaraldehyde method, maleimide method, pyridyl disulfide method or periodic acid method in the case of enzyme immunoassay, and chloramine T in the case of radioimmunoassay.
- a known method such as the Bolton Hunter method may be used.
- the measurement operation can be performed by a known method (Current-protocols-in-Protein-Sciences, 1995, John-Wiley & Sons Inc .; Current-protocols-in Immunology, 2001, John-Wiley & Sons Inc.).
- a direct detection method in which an anti-epithelial ovarian cancer marker antibody is labeled and the epithelial ovarian cancer marker in the sample is directly detected and quantified, or indirectly by using a labeled secondary antibody.
- an indirect detection method for detecting and quantifying automatically, but any method may be used in the present invention.
- the polypeptide fragment in the sample is immobilized and brought into contact with the labeled anti-epithelial ovarian cancer marker antibody, and then the epithelial ovarian cancer marker / labeled anti-epithelial ovarian cancer marker of the present invention.
- An antibody complex is formed.
- the unbound labeled antibody is washed and separated, and the amount of the epithelial ovarian cancer marker in the sample can be detected from the amount of bound labeled antibody or the amount of unbound labeled antibody, and the amount thereof can be measured.
- the epithelial ovarian cancer marker in the sample is reacted with the anti-epithelial ovarian cancer marker antibody which is the primary antibody (primary reaction), and further the labeled secondary antibody is reacted (secondary reaction).
- the primary reaction and the secondary reaction may be performed in reverse order or simultaneously.
- the labeled secondary antibody may specifically recognize and bind to the primary antibody, or may recognize and bind to the epithelial ovarian cancer marker.
- ovarian cancer marker / labeled secondary antibody consisting of epithelial ovarian cancer marker / anti-epithelial ovarian cancer marker antibody / labeled secondary antibody immobilized by primary reaction and secondary reaction, or immobilized anti-epithelial ovarian cancer marker antibody / epitheliality
- An ovarian cancer marker / labeled secondary antibody complex is formed.
- a method of forming a solid-phased anti-epithelial ovarian cancer marker antibody / epithelial ovarian cancer marker / labeled secondary antibody complex is called a sandwich method, and binds to the same antigen simultaneously.
- This is a method for detecting a target antigen using two different types of antibodies, that is, two or more types of monoclonal antibodies that recognize different epitopes on the same antigen (or one type of polyclonal antibody).
- sandwich method a so-called sandwich ELISA method in which one antibody of two kinds of antibodies is immobilized and the other antibody is labeled to detect a target antigen is frequently used. This method is used in the method of the present invention. Can also be suitably used.
- proteins other than epithelial ovarian cancer markers and unbound labeled secondary antibody contained in the sample are washed and separated, and the epithelium in the sample is determined from the amount of bound labeled secondary antibody or the amount of unbound labeled secondary antibody.
- the sex ovarian cancer marker can be detected and the amount thereof can be measured. It is preferable to use the indirect detection method by the sandwich method in that the epithelial ovarian cancer marker in the sample is measured with high accuracy without sacrificing sensitivity. This technique can also be applied to automation using an existing automatic immunodetection device.
- the anti-epithelial ovarian cancer marker antibody of the present invention (for example, any one of GT131-2 antibody, GT131-7 antibody, GT131-12 antibody or GT131-18 antibody) is immobilized on an insoluble carrier as a primary antibody.
- the surface of the solid phase on which the antibody is not immobilized is a protein unrelated to the antigen epithelial ovarian cancer marker (eg, calf serum, bovine serum albumin, gelatin, etc.) or sucrose, chemically synthesized polymer, etc. Block with a non-protein blocking agent.
- the immobilized primary antibody is brought into contact with the subject's sample.
- an anti-epithelial ovarian cancer marker antibody that recognizes and binds to an epitope different from the primary antibody on the epithelial ovarian cancer marker (in the above case, GT131-2 antibody, GT131-7 antibody, GT131-12 antibody)
- an antibody selected above from the group consisting of the GT131-18 antibody any one selected from the same group
- a secondary antibody a labeled secondary antibody labeled by the above method is used. Then, after washing and removing unbound labeled secondary antibody, a signal derived from the label from the labeled secondary antibody bound on the carrier may be detected.
- the determination of the incidence of epithelial ovarian cancer in a subject is based on the detection result by quantitatively and / or qualitatively detecting the epithelial ovarian cancer marker present in the sample derived from the subject. Do.
- Examples of the qualitative detection of epithelial ovarian cancer marker include detection by immunohistochemistry or Western blotting.
- the marker is determined based on the quantitative measurement result. If the quantitative value of the MGAT5B polypeptide fragment is equal to or greater than a predetermined value, it is determined that the subject is likely to have epithelial ovarian cancer.
- the “quantitative value” is a value obtained by the above-described measurement method, and may be an absolute value such as a concentration, or a signal by an epithelial ovarian cancer marker per unit sample. It may be a relative value such as intensity.
- the glycosyltransferase MGAT5B polypeptide fragment which is an epithelial ovarian cancer marker found by the present inventors, is usually hardly detected from a sample derived from a healthy person. Therefore, when a target MGAT5B polypeptide fragment is detected, in principle, it can be determined that the subject is likely to have epithelial ovarian cancer.
- a method using a quantitative value is preferable. That is, when the quantitative value of the MGAT5B polypeptide fragment is detected with a value equal to or higher than a predetermined value by the above measurement method, it may be determined that the subject is highly likely to have epithelial ovarian cancer.
- the “predetermined value” refers to a quantitative value that can separate an epithelial ovarian cancer patient and a healthy person, for example, a cutoff value. Specifically, for example, when the anti-epithelial ovarian cancer marker antibody of the present invention is used, a cut-off value described later can be mentioned.
- the anti-epithelial ovarian cancer marker antibody used is slightly cross-reactive and may detect other glycosyltransferases, or it is contaminated in healthy subjects or cancer patients other than epithelial ovarian cancer. If the non-specific reaction due to the substance cannot be excluded, there is a possibility that accurate determination cannot be made only by detecting the presence or absence of the epithelial ovarian cancer marker.
- the anti-epithelial ovarian cancer marker antibody to be used has cross-reactivity
- by detecting the epithelial ovarian cancer marker using the sandwich method described above its specificity is enhanced, Non-specific reactions due to contaminants can be significantly reduced. It has been confirmed that none of the GT131-2 antibody, GT131-7 antibody, GT131-12 antibody and GT131-18 antibody of the present invention show cross-reactivity.
- the measured value of the epithelial ovarian cancer marker in the sample derived from the subject is statistically compared with that of the healthy subject. Judgment may be made based on a scientifically significant high value.
- the quantitative value of the epithelial ovarian cancer marker obtained by the above quantification method can be used.
- the quantitative detection result of the subject and the healthy subject can be corrected.
- the amount of cancer marker can be obtained. Examples of such a protein for internal control include albumin.
- “Statistically significant” means that when a quantitative difference in epithelial ovarian cancer markers contained in samples derived from subjects and healthy subjects is statistically processed, there is a significant difference between the two That means. Specifically, for example, the risk rate (significance level) is less than 5%, 1%, or 0.1%.
- the test method for statistical processing is not particularly limited as long as a known test method capable of determining the presence or absence of significance is appropriately used. For example, Student's t test or multiple comparison test can be used.
- “statistically significantly high” means that in a multi-analyte analysis, patients with epithelial ovarian cancer and healthy subjects are optimized so that the sensitivity and specificity set by the conventional method are optimized. A value that can be separated is defined as a cutoff value, which is higher than the cutoff value.
- the cutoff value for separating an epithelial ovarian cancer affected person from a healthy person is , 4.0 ng / mL (95% tile above the peritoneal lavage fluid for gastric cancer patients with seeding), preferably 4.6 mLng / mL (the most distinction point when the ROC curve of the peritoneal lavage fluid for ovarian cancer patients vs. seeding is drawn)
- it is 14.3 ng / mL (lower 95% tile of ovarian cancer patient peritoneal lavage fluid). Therefore, when the quantitative value of the epithelial ovarian cancer marker in the sample of the subject is higher than the cut-off value, it can be determined that the subject is likely to have epithelial ovarian cancer. .
- Example 1 Preparation of anti-MGAT5B antibody and its antibody-producing hybridoma> 1.
- Selection and preparation of immunogens The MGAT5B gene used as an immunogen is derived from ovarian cancer cell lines RMG-I, RMG-II, RMG-V (above clear cell), and RMUG-S (mucous) for all 186 known glycosyltransferases.
- transcripts of normal tissues of peripheral blood cells, large intestine, liver and stomach were selected by real-time PCR analysis. Specifically, the transcription levels of the ovarian cancer cell line and normal tissue were ranked by comparing the average value and comparing the maximum value, and the higher glycosyltransferases were selected as ovarian cancer marker candidates.
- MGAT5B is one of them, the average value and the maximum value are both first, and the amount of transcription is significantly higher in ovarian cancer cells than in normal tissues. It was also higher than GAT (average value 14 and maximum value 13) and ⁇ 1,3-galactosyltransferase 4 (average value 32 and maximum value 17). Selected as a candidate.
- MGAT5B expression vector based on pIRESpuro3 was prepared for expression of MGAT5B gene.
- pFC3 Promega
- EcoRI EcoRI
- EcoRV EcoRI
- EcoRV EcoRI
- a plasmid containing the entire human MGAT5B gene sequence SEQ ID NO: 5
- primer A aaagaattccGGGGACTCGC: SEQ ID NO: 6
- primer B TACAGACAGCCCTG: SEQ ID NO: 7
- PCR was performed for 30 cycles at 94 ° C. for 30 seconds, followed by 55 ° C. for 30 seconds and 68 ° C. for 30 seconds.
- the amplification product was purified using Qiagen MinieluteelKit, digested with EcoRI and EcoRV, and inserted into the cleaved pFC3 (pFC3-MGAT5B).
- the obtained plasmid pFC3-MGAT5B has a region consisting of 51-position Gly to 372-Leu of MGAT5B shown in SEQ ID NO: 1, and preprotrypsin (MSALLILALVGAAVA: SEQ ID NO: 3) and FLAG (DYKDDDDK: SEQ ID NO: 4) on the N-terminal side thereof. ) And LAAANSE (linker) are linked to each other (soluble MGAT5B polypeptide fragment).
- the preprotrypsin sequence is cleaved when it is secreted from the cell.
- pFC3-MGAT5B was cleaved with restriction enzymes NruI and BamHI, and inserted into similarly cut pIRESpuro3 (Clontech). Thereby, the expression vector pIRES-F-puro3-MGAT5B was obtained.
- PIRES-F-puro3-MGAT5B was introduced into E. coli DH5 ⁇ , subcloned, and transfected into HEK293T using Lipofectamin2000 by a conventional method. Selection was performed under 10 ⁇ g / mL puromycin to obtain a constant expression strain.
- the target soluble MGAT5B polypeptide fragment was recovered with Anti-FLAG M2 Affinity Gel (A2220; Sigma), then subjected to SDS-PAGE, and monoclonal Anti-FLAG M2 Antibody Affinity purified (F1804; Sigma) was used. The expression was confirmed by Western blotting.
- the eluted fraction was concentrated to 500 ⁇ L by ultrafiltration, and then applied to a Superdex 200 10/300 GL (GE Healthcare) gel filtration column pre-equilibrated with a buffer (20 mM Tris-HCl, 50 mM NaCl, pH 8.0). Provided. Fractions were collected in 250 ⁇ L each, and each fraction was electrophoresed to obtain fractions containing soluble MGAT5B polypeptide fragments. After these were collected, the soluble MGAT5B polypeptide fragment preparation was obtained by concentrating to 2.5 mg / mL while replacing the solvent with PBS. This was used as an immunogen.
- the spleen of the mouse was removed, and the extracted spleen cells were washed with RPMI1640 medium.
- 1.2 ⁇ 10 8 spleen cell suspensions and 3 ⁇ 10 7 mouse myeloma cell (P3 / X63-Ag8.U1) suspensions were mixed, centrifuged, and the medium was removed. Fusion was carried out by gradually adding 2 mL of polyethylene glycol / RPMI1640 medium heated to 37 ° C. and gently stirring. Thereafter, the medium was removed by centrifugation, and 20% S-cron / cloning medium (Sanko Junyaku) and 60 mL of 10% FBS-containing RPMI1640 medium were added.
- HAT medium HAT medium x 1 concentration: 0.1 mM hypoxanthine, 0.4 ⁇ M aminopterin, 16 ⁇ M thymidine, 20% Escrown, 10% FBS-containing RPMI1640 medium
- Hybridoma The antibody search in the hybridoma culture supernatant was verified by ELISA using the MGAT5B polypeptide fragment prepared in “1. Selection and preparation of immunogen” described above as an antigen. First, the antigen was adsorbed to a microtiter plate for ELISA at a concentration of 1 ⁇ g / mL in PBS, blocked with PBS containing 5% sucrose and 5% Tween 20, and then the hybridoma culture supernatant was reacted.
- the target antibody was detected by reacting peroxidase-labeled goat anti-mouse immunoglobulin antibody and measuring absorbance at 450 nm using 3,3 ′, 5,5′-tetramethylbenzidine (TMB) as a substrate.
- TMB 3,3 ′, 5,5′-tetramethylbenzidine
- the hybridoma was cloned by the limiting dilution method.
- Cells were diluted to a density of about 1 per well in a 96-well plate and cultured in RPMI1640 medium containing 15% FBS. About 10 days later, the sample was examined under a microscope to confirm colony growth and number in the well. After about 14 days, 0.1 mL of the culture supernatant was collected, and antibody-producing cells were selected by ELISA using the supernatant.
- the 22 hybridomas obtained above were further cultured, and the immunoglobulin adsorbed on Protein-G agarose gel (GE Healthcare) was roughly purified from 10 mL of each culture supernatant.
- SDS-PAGE reduction conditions for FLAG-MGAT5B polypeptide fragment, MGAT5B polypeptide fragment cleaved and removed by enzymatic treatment, any different polypeptide fragment expressed using the same vector as FLAG-MGAT5B polypeptide fragment, and FBS A PVDF membrane transferred by electrophoresis below was prepared, and the above hybridoma-derived immunoglobulin prepared at a concentration of 1 ⁇ g / mL was reacted by Western blotting. Eleven hybridomas showed strong reactivity by Western blotting.
- the hybridoma was developed up to 100 mL in RPMI1640 medium containing 10% FBS and collected in the logarithmic growth phase. Disperse in 500 mL of RPMI1640 medium containing 2% FBS, ITS-A (10 mg / L insulin, 6.7 mg / L sodium selenate, 5.5 mg / L transferrin, 11.0 mg / L sodium pyruvate) went.
- the culture was further diluted 2-fold with the ITS-A-containing RPMI1640 medium and maintained from the 10th to the 14th days.
- culture supernatant derived from RPMI1640 medium containing 1 L of 1% FBS and ITS-A was obtained with two roller bottles. After removing cells by centrifugation and filtration, add NaCl, glycine, sodium azide and sodium hydroxide to prepare a culture supernatant to pH 8.9 containing 3M NaCl, 1.5M glycine and 0.1% sodium azide did.
- the antibody was bound through 4 mL of Protein A Sepharose affinity column (GE Healthcare) equilibrated with the same buffer (pH 8.9 containing 3M NaCl, 1.5M glycine and 0.1% sodium azide).
- the column was washed with 20 times the amount of the above buffer, and eluted with 0.1 M citrate buffer containing 0.1% sodium azide at pH 6.0, and the peak was fractionated with a fraction collector.
- the fractionated peak fraction was recovered and salted out with 50% saturated ammonium sulfate, and the precipitate after centrifugation was dissolved in 50 mM Tris buffer containing 0.15 M NaCl and 0.1% sodium azide, pH 8.0. In this way, approximately 10 to 40 mg of purified IgG was obtained for each of the six hybridomas.
- hybridomas GT131-2, GT131-7, GT131-12, and GT131-18 are deposited at the National Institute of Advanced Industrial Science and Technology, Patent Biological Deposit Center, as described above.
- Example 2 Confirmation of antigen specificity of monoclonal antibody> The antigen specificity of the hybridoma-derived anti-MGAT5B monoclonal antibody (GT131-12 antibody, GT131-18 antibody) obtained in Example 1 was verified.
- the mixture was reacted with purified MGAT5B monoclonal antibody (1 ⁇ g / mL) for 90 minutes at room temperature. After washing, it was mixed with an HRP-labeled anti-mouse IgG antibody (GE Healthcare) as a secondary antibody and reacted at room temperature for 60 minutes. After washing, detection was performed by chemiluminescence using a Western blotting detection reagent (Perkin Elmer).
- Example 3 Detection of MGAT5B polypeptide fragment by immunoprecipitation using anti-MGAT5B antibody> (Method) Healthy pool serum was diluted 100-fold with 50 mM Tris buffer (pH 8.0) containing 0.15 M NaCl and 0.1% sodium azide, and the FLAG-MGAT5B polypeptide fragment prepared in Example 1 was adjusted to a final concentration of 10 ⁇ g / mL. To give an immunoprecipitation sample.
- the FLAG-MGAT5B polypeptide fragment the above-mentioned GT131-2 antibody, GT131-7 antibody, GT131-12 antibody or GT131-18 antibody immunoprecipitation fraction, non-immunoprecipient healthy subject pool serum and FLAG-MGAT5B
- Each peptide fragment mixture was electrophoresed on a 10% polyacrylamide gel under SDS-PAGE reducing conditions and transferred to a PVDF membrane. After blocking with PBS containing 5% skim milk, it was reacted with HRP-labeled anti-FLAG antibody (M2, Sigma) for 1 hour at room temperature.
- GT131-12 antibody (2 ⁇ g / ml) or GT131-18 antibody (1 ⁇ g / ml) labeled with a biotin labeling kit (Dojindo Laboratories) at room temperature for 2 hours. After washing, it was reacted with HRP-labeled streptavidin (GE Healthcare) for 60 minutes at room temperature. These PVDF membranes were washed and then detected by chemiluminescence using a Western blotting detection reagent (Perkin Elmer).
- Example 4 Immunostaining of ovarian cancer cell line using anti-MGAT5B antibody> Using the anti-MGAT5B monoclonal antibody (GT131-2 antibody and GT131-18 antibody) prepared in Example 1, ovarian cancer cell lines were immunostained.
- FIG. a is a GT131-2 antibody
- b is a GT131-18 antibody
- c is an anti-B4GALT1 antibody which is a positive control of staining, and immunostained the epithelial ovarian cancer cell line RMUG-S.
- the part stained with the antibody is indicated by an arrow
- the part stained by the nucleus is indicated by an arrowhead. From these results, it was confirmed that epithelial ovarian cancer cells could be stained specifically for epithelial ovarian cancer markers using either GT131-2 antibody or GT131-18 antibody.
- the intracellular localization pattern of glycosyltransferase detected with anti-B4GALT1 antibody and the intracellular localization pattern of glycosyltransferase detected with GT131-2 antibody or GT131-18 antibody were the same. Therefore, MGAT5B was considered to be a glycosyltransferase localized in the Golgi apparatus. From this result, it was shown that the GT131-2 antibody and GT131-18 antibody of the present invention can be used for staining epithelial ovarian cancer cells and tissues.
- Example 5 Selection of antibody for sandwich ELISA measurement system> (Method) 6 types of anti-MGAT5B antibodies (GT131-2 antibody, GT131-7 antibody, GT131-9 antibody, GT131-12 antibody, GT131-14 antibody and GT131-18 antibody) obtained in Example 1 were respectively immobilized on the ELISA plate.
- the sandwich ELISA assay system was used on the detection side. First, each antibody was diluted with PBS to 4 ⁇ g / mL and added to an ELISA microplate at 100 ⁇ L / well. After each antibody was adsorbed to the plate at 4 ° C. overnight, the solution was discarded and the wells were washed.
- 3% bovine albumin (BSA) -containing PBS was added as a blocking solution at 300 ⁇ L / well for blocking.
- the blocking solution was discarded and washed, and 100 ⁇ L of a solution of MGAT5B polypeptide fragment prepared at 0, 31.25, 62.5, 125, 250, 500 ng / mL was added to each well. After reacting at 37 ° C.
- TMB substrate solution (Pierce) was measured at an absorbance of 450 nm.
- One of the six monoclonal antibodies obtained in Example 1 (GT131-9) was weakly reactive, and two (GT131-14 and GT131-18) did not react with each other's sandwich ELISA. It was inferred that the same site was recognized.
- the other four monoclonal antibodies GT131-2, GT131-7, GT131-12, and GT131-18 reacted depending on the MGAT5B concentration when any combination was used, and all four were used in the sandwich ELISA assay system. It was shown that it can.
- the results are shown in FIG. Among these, as a preferred combination for detecting the antigen MGAT5B, the monoclonal antibody GT131-12 was used for immobilizing the microplate, and the monoclonal antibody GT131-7 was used for detection in the following examples.
- Example 6 Construction of a highly sensitive sandwich CLEIA measurement system>
- chemiluminescence chemiluminescent enzyme immunoassay
- Chemiluminescent Enzyme Immunoassay CLEIA The application of the law was examined.
- the GT131-12 antibody of the present invention was prepared at 4 ⁇ g / mL, added to a 96-well microplate for fluorescence photometry (Nunc) at 100 ⁇ L / well, and fixed at room temperature for 7 hours. After discarding the antibody solution, wash with PBS containing 0.05% Tween20, and add blocking solution (0.2% high-purity casein (I-Block, Life Technologies), 0.1% Tween20, 20 mM Tris-pH 8.0 containing 0.15M NaCl). Added at 300 ⁇ L / well and blocked overnight at 4 ° C.
- MGAT5B polypeptide fragment was prepared to 0, 0.6125, 1.25, 2.5, 5, 10, 20, 40, 80, 160 ng / mL with the above blocking solution. 10 ⁇ L of each concentration standard product was added to the washed microplate together with 90 ⁇ L of blocking solution and reacted at 37 ° C. for 2 hours. After the reaction, it was washed 5 times with PBS containing 0.05% Tween20 and GT131-7 antibody labeled with alkaline phosphatase using the alkaline phosphatase labeling kit (Dojindo Laboratories) was prepared to 0.5 ⁇ g / mL with the above blocking solution. / Well and allowed to react for 1 hour and a half in the dark at room temperature.
- FIG. 5 shows a standard curve obtained from the measured values of the standard concentration product. Confirmed that the glycosyltransferase MGAT5B polypeptide fragment in a sample derived from a subject can be quantified with a detection sensitivity of about 1 ng / mL by sandwich CLEIA using the GT131-12 antibody and GT131-7 antibody of the present invention. It was done. Using this standard curve, the concentration of the MGAT5B polypeptide fragment present in the sample obtained from the subject can be determined.
- Example 7 Measurement of amount of MGAT5B polypeptide fragment in peritoneal lavage fluid etc. of epithelial ovarian cancer patient> (Method)
- Experimental example 1 Using the standard curve of the MGAT5B polypeptide fragment obtained in Example 6 and the sandwich CLEIA method, 40 peritoneal lavage fluids collected from patients with epithelial ovarian cancer, and peritoneal lavage fluids collected from gastric cancer patients with intraperitoneal dissemination as the control group Using 55 cases and 159 cases of peritoneal lavage fluid from gastric cancer patients without intraperitoneal dissemination, the concentration of the epithelial ovarian cancer marker (MGAT5B polypeptide fragment) in each sample was quantitatively measured. About the detail of the measuring method, it carried out according to the method as described in Example 6. FIG.
- the cut-off value is set to 4.6 ng / mL. From these samples, it was proved that the incidence of epithelial ovarian cancer can be determined with a high accuracy rate.
- the concentration of the MGAT5B polypeptide fragment did not correlate with any measured values of the existing ovarian cancer markers CA125 (a) and GAT (b).
- the concentration of the MGAT5B polypeptide fragment did not correlate with any measured values of the existing ovarian cancer markers CA125 (a) and GAT (b).
- a positive correlation was observed between the measured CA125 value and the measured GAT value, and the correlation coefficient was 0.65. From these results, it was suggested that the measured value of the MGAT5B polypeptide fragment according to the present invention reflects a disease state secreted by a mechanism different from that of the existing ovarian cancer marker.
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Abstract
Description
(1)配列番号1で示すアミノ酸配列からなるポリペプチドの一部をエピトープとして認識する上皮性卵巣癌マーカー検出用抗体。
(2)モノクローナル抗体である、(1)に記載の抗体。
(3)国際受領番号がFERM ABP-11496、FERM ABP-11497、FERM ABP-11498又はFERM ABP-11499であるハイブリドーマにより産生される、(2)に記載の抗体。
(5)前記(1)~(3)のいずれかに記載の抗体又は(4)に記載の組換え抗体の断片であって、MGAT5Bを特異的に認識する活性を有する上皮性卵巣癌マーカー検出用抗体断片。
(6)前記(2)に記載の抗体を産生するハイブリドーマ。
(7)国際受領番号がFERM ABP-11496である、(6)に記載のハイブリドーマ。
(8)国際受領番号がFERM ABP-11497である、(6)に記載のハイブリドーマ。
(9)国際受領番号がFERM ABP-11498である、(6)に記載のハイブリドーマ。
(10)国際受領番号がFERM ABP-11499である、(6)に記載のハイブリドーマ。
(12)前記MGAT5Bポリペプチド断片の定量検出結果においてMGAT5Bポリペプチド断片の定量値が所定の値以上であった場合、その被験者は上皮性卵巣癌に罹患している可能性が高いと判定する、(11)に記載の上皮性卵巣癌判定方法。
(13)前記MGAT5Bポリペプチド断片が配列番号1に示されるアミノ酸配列からなるポリペプチドの全部又は一部である、(11)又は(12)に記載の上皮性卵巣癌判定方法。
(14)MGAT5Bポリペプチド断片を(1)~(3)のいずれかに記載の抗体、(4)に記載の組換え抗体及び(5)に記載の抗体断片からなる群より選択される少なくとも1つの抗体、組換え抗体及び/又は抗体断片を用いて検出する、(11)~(13)のいずれかに記載の上皮性卵巣癌判定方法。
(15)MGAT5Bポリペプチド断片上の異なるエピトープを認識する2つの抗体、組換え抗体及び/又は抗体断片を用いる、(14)に記載の上皮性卵巣癌判定方法。
(16)前記試料が、体液、腹腔洗浄液又は組織である、(11)~(15)のいずれかに記載の上皮性卵巣癌判定方法。
本明細書は本願の優先権の基礎である日本国特許出願2011-163323号の明細書及び/又は図面に記載される内容を包含する。
1-1.定義及び構成
本発明の第1の実施形態は、上皮性卵巣癌マーカー検出用抗体である。本発明の抗体は、上皮性卵巣癌マーカーを検出するために用いる抗体であって、上皮性卵巣癌マーカーに含まれるエピトープを認識し、それに特異的に結合することを特徴とする。
本発明の抗MGAT5B抗体、すなわち抗MGAT5Bポリクローナル抗体及び抗MGAT5Bモノクローナル抗体、又は抗MGAT5Bモノクローナル抗体を産生するハイブリドーマは、以下に記載する方法によって作製することができる。ただし、下記方法に限定されるものではなく、当該分野で公知の他のあらゆる方法を用いて作製することもできる。
免疫原としての上皮性卵巣癌マーカーを調製する。本発明において免疫原として使用可能な上皮性卵巣癌マーカーは、例えば、配列番号1に示されるアミノ酸配列を有するヒトMGAT5Bポリペプチド断片の全部又は一部、あるいはその変異体のポリペプチド断片の全部又は一部である。
MGAT5B cDNAは、公知の技術、例えば、cDNAクローニング法によって調製することができる。具体的には、まず、ヒトcDNAライブラリーを作製する。ヒトcDNAライブラリーは、MGAT5B遺伝子等を発現するヒト線維芽細胞(neuroblastoma cell line SK-N-SH)等から常法に基づいて総RNAを抽出した後、オリゴdTセルロースカラムで処理してポリA(+)RNAを回収し、それを鋳型としてRT-PCR法によって作製することができる。この他、市販のヒトcDNAライブラリーを利用してもよい。
次に、上記得られたMGAT5B cDNAクローンを発現ベクターに組み込む。具体的には、例えば、プラスミド又はウイルスを利用した発現ベクターが挙げられる。発現ベクターは、発現宿主に応じて、大腸菌用発現ベクター(例えば、pET21α系、pGEX4T系、pUC118系、pUC119系、pUC18系、pUC19系)、枯草菌由来発現ベクター(例えば、pUB110系、pTP5系)、酵母由来発現ベクター(例えば、YEp13系、YEp24系、YCp50系)、昆虫細胞用発現ベクター(例えば、バキュロウイルス)、動物細胞用発現ベクター(例えば、pA1-11、pXT1、pRc/CMV、pRc/RSV、pcDNAI/Neo)を利用することができる。発現ベクターは、通常、調節エレメントとして、例えば、プロモータ、ターミネータ、エンハンサ、ポリアデニル化シグナル、複製開始点、選択マーカー等を含むことができる。また、目的のcDNA断片のクローニング用として、マルチクローニング部位や、精製を容易にするための標識ペプチド(タグ)との融合ポリペプチドとして発現するように、cDNA断片の挿入部位の5’末端側又は3’末端側にタグ配列を有するものを用いてもよい。さらに挿入部位の5’末端側に分泌シグナル配列をコードする配列を有するものを用いてもよい。これによって細胞外に発現した成熟ポリペプチドを分泌させることができる。このような発現ベクターや他の発現系は、各メーカー(タカラバイオ社、第一化学薬品、Agilent Technologies社、Merck社、Qiagen社、Promega社、Roche Diagnostics社、Life Technologies社、GE Healthcare社等)から有用な製品が市販されているので、それらを利用してもよい。MGAT5B cDNAを発現ベクターに挿入するには、精製されたMGAT5B cDNAを適当な制限酵素で切断し、発現ベクター側の対応する適当な制限部位に挿入してベクターと連結させればよい。必要に応じて、発現ベクターに組み込む前に、適当なプラスミド等を用いてMGAT5B cDNAをサブクローニングしてもよい。
続いて、得られたMGAT5B発現系(例えば、MGAT5B発現ベクター)を宿主細胞に導入し、免疫原である目的のMGAT5Bポリペプチド断片を発現させる。
次に、宿主細胞内で生産されたMGAT5Bポリペプチド断片を、細胞内又は培養上清から回収する。生産されたMGAT5Bポリペプチド断片が菌体内又は細胞内に蓄積される場合には、その菌体又は細胞を破砕してタンパク質を抽出する。また、MGAT5Bポリペプチド断片が菌体外又は細胞外に生産される場合には、培養液をそのまま使用するか、遠心分離等により菌体又は細胞を除去し、上清を使用すればよい。その後、一般的なタンパク質の精製方法を用いることによって、MGAT5Bポリペプチド断片を単離精製することができる。MGAT5Bポリペプチド断片が標識ペプチド(タグ)との融合ペプチドとして発現する場合には、例えば、各標識ペプチドに適したアフィニティークロマトグラフィー法を利用すればよい。また、標識ペプチドのないMGAT5Bポリペプチド断片として発現する場合には、例えば、硫酸アンモニウム塩析法、ゲルクロマトグラフィー法、イオン交換クロマトグラフィー法、疎水性クロマトグラフィー法、等電点クロマトグラフィー法等を利用すればよい。あるいは、前記二以上の精製方法を適宜組み合わせて単離精製することもできる。
得られたMGAT5Bポリペプチド断片を免疫原として、該ポリペプチドを特異的に認識する抗MGAT5Bポリクローナル抗体を得ることができる。
抗MGAT5Bモノクローナル抗体の作製は、ケラー&ミルシュタインの方法で調製することができる(Nature 256:495-497 (1975))。例えば、前記免疫した動物から得られる抗体産生細胞と、骨髄腫(ミエローマ)細胞との細胞融合によりハイブリドーマを調製し、得られたハイブリドーマから抗MGAT5Bモノクローナル抗体を産生するクローンを選択することにより調製することができる。以下で、具体例を挙げて説明するが、本発明の抗体の作製は、以下の方法に限定されるものではない。
まず、上記免疫したマウスから抗体産生細胞を採取する。採取は、最終免疫の日から2~5日後が好ましい。抗体産生細胞としては、脾細胞、リンパ節細胞、末梢血細胞等が挙げられるが、脾細胞又は局所リンパ節細胞が好ましい。マウスからの抗体産生細胞の採取方法は、当該分野で公知の技術に従って行えばよい。
続いて、抗体産生細胞と骨髄腫(ミエローマ)細胞との細胞融合を行うことで、抗MGAT5Bモノクローナル抗体を生産するハイブリドーマを作製することができる。
抗MGAT5Bモノクローナル抗体は、慣用的技術によって回収可能である。例えば、樹立したハイブリドーマから回収する方法として、通常の細胞培養法又は腹水形成法等を採用することができる。細胞培養法においては、抗MGAT5Bモノクローナル抗体産生ハイブリドーマを10%FBS含有RPMI1640培地、MEM培地又は無血清培地等の動物細胞培養培地中で、例えば、37℃、5%CO2濃度で2~10日間培養し、その培養上清から抗体を取得する。腹水形成法の場合は、ミエローマ細胞由来の哺乳動物と同種系動物(上記方法の場合は、マウス)の腹腔内に抗MGAT5Bモノクローナル抗体産生ハイブリドーマを約1000万個投与し、該ハイブリドーマを大量に増殖させる。そして、1~2週間後に腹水又は血清を採取することによって、回収できる。このような方法によって、前述の抗MGAT5Bモノクローナル抗体産生ハイブリドーマの具体例として挙げた、GT131-2、GT131-7、GT131-12及びGT131-18からも、それぞれ「GT131-2抗体」、「GT131-7抗体」、「GT131-12抗体」及び「GT131-18抗体」を得ることができる。
本発明の抗MGAT5B抗体、後述する上皮性卵巣癌マーカー検出用組み換え抗体及び/又は上皮性卵巣癌マーカー検出用抗体断片は、上皮性卵巣癌マーカーと特異的に反応するため、上皮性卵巣癌検出試薬における有効成分として用いることができる。この検出試薬を用いて、被験者から採取した試料中に含まれる上皮性卵巣癌マーカーを検出することによって、被験者の上皮性卵巣癌の罹患を判定することもできる。
本発明の抗MGAT5B抗体は、上皮性卵巣癌マーカーである糖転移酵素MGAT5Bのゴルジ体内領域を特異的に認識し、結合することができる。したがって、本発明の抗MGAT5B抗体を用いることで、被験者の試料から上皮性卵巣癌マーカーを効率的に検出できる。
2-1.定義及び構成
本発明の第2の実施形態は、上皮性卵巣癌マーカー検出用組換え抗体である。本発明の組換え抗体は、第1実施形態に記載の上皮性卵巣癌マーカー検出用抗体における対応する軽鎖相補鎖決定領域(CDR:Complementarity determining region)及び重鎖CDRを少なくとも一組含むことを特徴とする。本明細書では、「上皮性卵巣癌マーカー検出用組換え抗体」をしばしば「抗MGAT5B組換え抗体」と表記する。
抗MGAT5B組換え抗体は、第1実施形態で作製された抗MGAT5B抗体を用いて、当該分野で公知のDNAクローニング技術によって作製すればよい。例えば、上記それぞれで引用した文献の他にも、Sambrook, J. et. al., (1989) Molecular Cloning: A Laboratory Manual Second Ed., Cold Spring Harbor Laboratory Press, Cold Spring Harbor, New Yorkを参照することができる。
本発明の抗MGAT5B組換え抗体は、第1実施形態の抗MGAT5B抗体と同様に、上皮性卵巣癌マーカーである糖転移酵素MGAT5Bのゴルジ体内領域を特異的に認識し、結合することができる。したがって、本発明の抗MGAT5B組換え抗体を用いることで、被験者の試料から上皮性卵巣癌マーカーを効率的に検出できる。
3-1.定義及び構成
本発明の第3の実施形態は、上皮性卵巣癌マーカー検出用抗体断片である。
本発明の上皮性卵巣癌マーカー検出用抗体断片は、第1実施形態の抗MGAT5B抗体と同様に、上皮性卵巣癌マーカーである糖転移酵素MGAT5Bのゴルジ体内領域を特異的に認識し、結合することができる。したがって、本発明の上皮性卵巣癌マーカー検出用抗体断片を用いることで、被験者の試料から上皮性卵巣癌マーカーを効率的に検出できる。
本発明の第4の実施形態は、上皮性卵巣癌判定方法である。本発明の上皮性卵巣癌判定方法は、被験者由来の試料中に存在する上皮性卵巣癌マーカーを定量的及び/又は定性的に検出し、その検出結果に基づいて、その被験者における上皮性卵巣癌の罹患の有無を判定する。
本明細書において「被験者」とは、本発明の方法において検査に供される者、すなわち後述する試料を提供する者をいう。好ましい被験者は、上皮性卵巣癌に罹患しているおそれがある者又は上皮性卵巣癌患者である。なお、本明細書において、「健常者」とは、上皮性卵巣癌に関して健常である広義の健常者、すなわち、上皮性卵巣癌非罹患者をいう。したがって、上皮性卵巣癌に罹患していなければ、他の疾患、例えば、胃癌や子宮癌等に罹患している者であっても構わない。好ましくはいずれの疾患にも罹患していない狭義の健常者、すなわち健康者である。
試料中の上皮性卵巣癌マーカーを検出する方法は、ポリペプチドである当該マーカーを検出できる公知の方法であれば、いずれの方法を用いてもよい。好ましくは上皮性卵巣癌マーカーを特異的に認識して、それに結合する抗体を用いる免疫学的反応を利用した検出方法(免疫学的検出法)である。
被験者の上皮性卵巣癌罹患の判定は、上記被験者由来の試料中に存在する上皮性卵巣癌マーカーを定量的及び/又は定性的に検出し、その検出結果に基づいて行う。
1.免疫原の選択と調製
免疫原となるMGAT5B遺伝子は、公知糖転移酵素全186種について卵巣癌細胞株RMG-I、RMG-II、RMG-V(以上明細胞性)、RMUG-S(粘液性)と末梢血細胞、大腸、肝臓、胃の正常組織の転写産物をリアルタイムPCR法にて解析することによって選択された。具体的には、卵巣癌細胞株と正常組織それぞれの転写量について、平均値の比較、及び最大値の比較による順位付けを行い、上位の糖転移酵素を卵巣癌マーカー候補として選択した。MGAT5Bは、そのうちの一つであり、平均値及び最大値がいずれも1位であり正常組織と比較して卵巣癌細胞で著しく転写量が多い。またGAT(平均値14位及び最大値13位)及びβ1,3-ガラクトース転移酵素4(平均値32位及び最大値17位)よりも高位であったことから、卵巣癌に特異的な有力マーカー候補として選択された。
上記で調製した免疫原である可溶型MGAT5Bポリペプチド断片50μgを0.1mLの生理食塩水に溶解した後、フロイント完全アジュバント0.1mLを加えて充分に混合し、エマルションを調製した。0.2mLのエマルションを、Balb/cマウス(9週齢雌)の背面皮下に注射した。初回免疫から1週間後に、0.05mLの生理食塩水に25μgの免疫原を溶解した免疫原溶液に0.05mLのアルミニウムアジュバントを加え、十分に混合したエマルションを前記マウスの腹腔内に注射した。さらに、初回免疫から4週間後に生理食塩水0.1mLに免疫原50μgを溶解したものを、また初回免疫から5週間後に生理食塩水0.05mLに免疫原25μgを溶解したものを、それぞれ腹腔内に注射した。
ハイブリドーマ培養上清中の抗体の検索は、上記「1.免疫原の選択と調製」で調製したMGAT5Bポリペプチド断片を抗原として、ELISA法を用いて検証した。まず、抗原をPBS中1μg/mLの濃度でELISA用マイクロタイタープレートに吸着させ、5%スクロース及び5%Tween20含有PBSにてブロッキングした後、ハイブリドーマ培養上清を反応させた。さらに、ペルオキシダーゼ標識ヤギ抗マウス免疫グロブリン抗体を反応させ、基質として3,3’,5,5’-テトラメチルベンジジン(TMB)を用いて450nmにおける吸光度を測定することにより目的の抗体を検出した。その結果、合計18個のウェルで抗体産生ハイブリドーマが得られた。これらのハイブリドーマは、HAT培地からアミノプテリンを除いたHT培地に移し、さらに10%FBS含有RPMI1640培地に移して培養した。
具体的には、10%FBS含有RPMI1640培地中でハイブリドーマを100mLまで展開し、対数増殖期に回収した。2%FBS、ITS-A(10mg/Lインスリン、6.7mg/Lセレン酸ナトリウム、5.5mg/Lトランスフェリン、11.0mg/Lピルビン酸ナトリウム)含有RPMI1640培地500mLに分散させて、ローラーボトルによる回転培養を行った。回転培養開始2日目~4日目にITS-A含有RPMI1640培地でさらに2倍希釈し10日目~14日目まで維持した。最終的に、ローラーボトル2本で1Lの1%FBS、ITS-A含有RPMI1640培地由来の培養上清を得た。遠心と濾過により細胞を除去した後、NaCl、グリシン、アジ化ナトリウム及び水酸化ナトリウムを添加して、3M NaCl、1.5Mグリシン、0.1%アジ化ナトリウム含有pH8.9となるよう培養上清を調製した。その後、同じ緩衝液(3M NaCl、1.5Mグリシン、0.1%アジ化ナトリウム含有pH8.9)で平衡化したプロテインAセファロースアフィニティカラム4mL(GE Healthcare社)を通し抗体を結合させた。次に、カラムをカラムの20倍量の上記緩衝液で洗浄後、pH6.0の0.1%アジ化ナトリウム含有0.1Mクエン酸緩衝液で溶出し、フラクションコレクターでピークを分画した。分画したピーク画分は回収後50%飽和硫酸アンモニウムで塩析し、遠心分離後の沈殿物を0.15M NaCl、0.1%アジ化ナトリウム含有pH8.0の50mMトリス緩衝液で溶解した。このようにして、ハイブリドーマ6個についてそれぞれ約10~40mgの精製IgGを得た。
実施例1で得たハイブリドーマ由来の抗MGAT5Bモノクローナル抗体(GT131-12抗体、GT131-18抗体)の抗原特異性について検証した。
実施例1で得たFLAG-MGAT5Bポリペプチド断片を10ng、及び該断片から酵素処理によってFLAGタグを切断したMGAT5Bポリペプチド断片を10ng、複数の健常者から得た血清を混合した健常者プール血清から免疫グロブリン及びアルブミンを除去した血清を1μL、健常者プール血清を0.5μLをそれぞれSDS-PAGE還元条件下で10%ポリアクリルアミドゲルを用いて電気泳動し、PVDF膜に転写した。5%スキムミルク含有PBSでブロッキング後、精製MGAT5Bモノクローナル抗体(1μg/mL)と室温で90分反応させた。洗浄後、二次抗体としてHRP標識抗マウスIgG抗体(GE Healthcare社)と混合して室温で60分反応させた。洗浄後、ウェスタンブロッティング検出試薬(Perkin Elmer社)により化学発光にて検出した。
結果を図1に示す。GT131-12抗体及びGT131-18抗体は、いずれもFLAG-MGAT5Bポリペプチド断片及びFLAGタグを切断、除去したMGAT5Bポリペプチド断片と、十分に結合することが確認された。しかし、健常者の血清に対しては、反応は弱い(GT131-12抗体)か、又は反応しなかった(GT131-18抗体)。この結果から、GT131-12抗体及びGT131-18抗体は、MGAT5Bポリペプチド断片と特異的に反応し、ヒト血清中に含まれる他のタンパク質とは反応しないことが立証された。
(方法)
健常者プール血清を0.15M NaCl、0.1%アジ化ナトリウム含有50mMトリス緩衝液(pH8.0)で100倍に希釈し、実施例1で調製したFLAG-MGAT5Bポリペプチド断片を最終濃度10μg/mLとなるように添加して、それを免疫沈降試料とした。この試料各0.5mLにモノクローナル抗体(GT131-2抗体、GT131-7抗体、GT131-12抗体又はGT131-18抗体)を2μg、及びプロテインGゲル(GE Healthcare社)を20μL加えて、ローテーターで4℃にて4時間混和した。遠心分離によりサンプル溶液を廃棄し、プロテインGゲルを上記トリス緩衝液で洗浄後、SDS-PAGEサンプルバッファー40μLを加え、98℃で5分間加熱し免疫沈降画分を得た。
結果を図2に示す。サンプルとして添加したFLAG-MGAT5Bポリペプチド断片が、いずれの免疫沈降画分からも検出された。これらにより本発明のモノクローナル抗体GT131-2抗体、GT131-7抗体、GT131-12抗体又はGT131-18抗体のいずれも、血清のような夾雑物の多いタンパク質溶液からでもMGAT5Bポリペプチド断片を特異的に免疫沈降できることが示された。
実施例1で調製した抗MGAT5Bモノクローナル抗体(GT131-2抗体及びGT131-18抗体)を用いて、卵巣癌細胞株の免疫染色を行った。
上皮性卵巣癌細胞RMUG-S株にGT131-2抗体産生ハイブリドーマの培養上清(GT131-2抗体を含む)、GT131-18抗体産生ハイブリドーマの培養上清(GT131-18抗体を含む)、又はトランスゴルジマーカーとして利用されている抗B4GALT1モノクローナル抗体MAb8628(Uemura M.et al., 1992, Cancer Res., 52:6153-6157)を添加し、4℃で一晩反応させた後、Anti-mouse alexa488(Life Technologies社)を用いて各種糖転移酵素と結合した抗体反応を可視化した。核をヘキスト33342(Life Technologies社)で染色し、キーエンス顕微鏡のBioZeroを使って、画像を取得した。
結果を図3に示す。aはGT131-2抗体で、bはGT131-18抗体で、そしてcは染色の陽性コントロールである抗B4GALT1抗体で、上皮性卵巣癌細胞株RMUG-Sをそれぞれ免疫染色した図である。抗体で染色された部分を矢印で、核染色された部分を矢頭で示す。この結果から、GT131-2抗体及びGT131-18抗体のいずれを用いても、上皮性卵巣癌細胞を上皮性卵巣癌マーカー特異的に染色できることが確認された。抗B4GALT1抗体で検出される糖転移酵素の細胞内局在パターンと、GT131-2抗体又はGT131-18抗体で検出される糖転移酵素の細胞内局在パターンは、同一であった。したがって、MGAT5Bは、ゴルジ体に局在する糖転移酵素と考えられた。この結果から、本発明のGT131-2抗体及びGT131-18抗体を上皮性卵巣癌細胞及び組織の染色に用いることができることが示された。
(方法)
実施例1で得た抗MGAT5B抗体6種(GT131-2抗体、GT131-7抗体、GT131-9抗体、GT131-12抗体、GT131-14抗体及びGT131-18抗体)をそれぞれELISAプレート固相化側と検出側に用いサンドイッチELISA測定系の検討を行った。まず、各抗体をPBSで4μg/mLとなるように希釈し、ELISA用マイクロプレートに100μL/ウェルずつ添加した。4℃で一晩各抗体をプレートに吸着させた後、溶液を廃棄して、ウェルを洗浄した。次に、3%ウシアルブミン(BSA)含有PBSをブロッキング液として300μL/ウェルで加えて、ブロッキングをした。前記ブロッキング液を廃棄し、洗浄した後、0、31.25、62.5、125、250、500ng/mLに調製したMGAT5Bポリペプチド断片の溶液100μLを各ウェルに添加した。37℃で2時間反応させた後、ウェル中の溶液を廃棄し、洗浄した後、ビオチンラベリングキット(同仁化学研究所)を用いてビオチン標識化した6種の抗体(GT131-2抗体、GT131-7抗体、GT131-9抗体、GT131-12抗体、GT131-14抗体及びGT131-18抗体)をそれぞれ1μg/mLに調製して、室温で2時間反応させた.その後、溶液を廃棄して洗浄後、西洋ワサビペルオキシダーゼ(HRP)標識アビジン(Jackson社)溶液を1ウェルに100μL加えて1時間室温にて反応させた。反応液を廃棄、洗浄した後、TMB基質液(Pierce社)による発色を450nmの吸光度で測定した。実施例1で得たモノクローナル抗体6種のうち1種(GT131-9)は反応性が弱く、また2種(GT131-14とGT131-18)は互いのサンドイッチELISAでは反応が出なかったことから、同一部位を認識していることが推察された。その他の4種のモノクローナル抗体GT131-2、GT131-7、GT131-12及びGT131-18はいずれの組み合わせを用いた場合もMGAT5B濃度依存的に反応が見られ、4種ともサンドイッチELISA測定系に用いることができることが示された。結果を図4に示す。この中から抗原MGAT5Bを検出するに当たり好ましい組み合わせとして、マイクロプレート固相化用としてモノクローナル抗体GT131-12と、検出用としてモノクローナル抗体GT131-7を以後の実施例で用いることとした。
実施例5で選択したモノクローナル抗体GT131-7抗体とGT131-12抗体の組み合わせによるサンドイッチELISA測定系の感度を上げるため、化学発光を用いた検出系(化学発光酵素免疫測定法、Chemiluminescent Enzyme Immunoassay;CLEIA法)の適用を検討した。
本発明のGT131-12抗体を4μg/mLに調製し、蛍光測光用96ウェルマイクロプレート(Nunc社)に100μL/ウェルずつ添加して、室温で7時間固定した。抗体溶液を廃棄した後、0.05% Tween20含有PBSで洗浄し、ブロッキング液(0.2%高純度カゼイン(I-Block、Life Technologies社)、0.1% Tween20、0.15M NaCl含有20mMトリス-pH8.0)を300μL/ウェルで加え、4℃で一晩ブロッキングした。濃度標準品としてMGAT5Bポリペプチド断片を、上記ブロッキング液で0、0.6125、1.25、2.5、5、10、20、40、80、160ng/mLに調製した。各濃度標準品10μLを90μLのブロッキング液と共に上記洗浄後のマイクロプレートに添加して37℃で2時間反応させた。反応後、0.05% Tween20含有PBSで5回洗浄し、アルカリフォスファターゼラベリングキット(同仁化学研究所)を用いてアルカリフォスファターゼ標識したGT131-7抗体を上記ブロッキング液で0.5μg/mLに調製して、100μL/ウェルで添加し、室温、暗所で1時間半反応させた。反応後、0.05% Tween20含有PBSで4回、1mM塩化マグネシウム含有20mMトリス(pH9.8)で2回洗浄して、化学発光試薬CSPD Substrate Sapphire-II(Life Technologies社)を1ウェルに100μLを添加し、室温、暗所で反応させて、45分後に発光強度を測定した。
図5に濃度標準品の測定値より得た標準曲線を示す。本発明のGT131-12抗体及びGT131-7抗体を用いたサンドイッチCLEIA法により、検出感度約1ng/mLで被検者由来の試料中の糖転移酵素MGAT5Bポリペプチド断片を定量することができることが確認された。この標準曲線を用いて被験者から得た試料中に存在するMGAT5Bポリぺプチド断片の濃度を求めることができる。
(方法)
(1)実験例1
実施例6で得たMGAT5Bポリペプチド断片の標準曲線とサンドイッチCLEIA法を用いて、上皮性卵巣癌患者から採取した腹腔洗浄液40例、その対照群として腹腔内播種のある胃癌患者から採取した腹腔洗浄液55例、及び腹腔内播種のない胃癌患者の腹腔洗浄液159例を試料として、それぞれの試料中における上皮性卵巣癌マーカー(MGAT5Bポリペプチド断片)の濃度を定量的に測定した。測定方法の詳細については、実施例6に記載の方法に準じて行った。
また、上記実験例1で用いた上皮性卵巣癌患者から採取した腹腔洗浄液40例を試料として、各試料における既存の卵巣癌マーカーCA125及びGATを測定した。CA125は、Abnova社のCA125 (Human) ELISAキット(カタログNo.:KA0205)、GATは、コニカミノルタ社のGATテストキットを用いて、それぞれの添付のプロトコールに従い測定した。得られたそれぞれのマーカーの測定値を、実験例1で得た卵巣癌患者腹腔洗浄液40例のMGAT5Bポリペプチド断片の濃度測定値と比較した。
実験例1の結果を図6に、また比較例1の結果を図7及び図8に示す。
まず、図6に示すように、測定値(上皮性卵巣癌マーカー濃度)の統計解析を行ったところ、上記3群にはそれぞれ有意差があった。特に胃癌の2群と比較して卵巣癌では有意に高い測定値を示し、その平均値は、卵巣癌患者検体で19.6ng/mL、播種のある胃癌患者検体で3.3ng/mL、播種のない胃癌患者検体で2.1ng/mLであった。この結果から、本発明の2つの抗MGAT5B抗体、すなわちGT131-7抗体及びGT131-12抗体を用いたサンドイッチCLEIA法を用いて、そのカットオフ値を4.6ng/mLに設定することで、被験者由来の試料から上皮性卵巣癌の罹患を高い正診率で判定できることが立証された。
本明細書で引用した全ての刊行物、特許及び特許出願をそのまま参考として本明細書にとり入れるものとする。
GT131-7;国内受託番号:FERM P-22098;国際受領番号:FERM ABP-11497
GT131-12;国内受託番号:FERM P-22099;国際受領番号:FERM ABP-11498
GT131-18;国内受託番号:FERM P-22100;国際受領番号:FERM ABP-11499
Claims (16)
- 配列番号1で示すアミノ酸配列からなるポリペプチドの一部をエピトープとして認識する上皮性卵巣癌判定用抗β1,6-N-アセチルグルコサミン転移酵素5B抗体。
- モノクローナル抗体である、請求項1に記載の抗体。
- 国際受領番号がFERM ABP-11496、FERM ABP-11497、FERM ABP-11498又はFERM ABP-11499であるハイブリドーマにより産生される、請求項2に記載の抗体。
- 請求項1~3のいずれか一項に記載の抗体に存在する少なくとも1組の対応する軽鎖相補鎖決定領域及び重鎖相補鎖決定領域を含む上皮性卵巣癌判定用抗β1,6-N-アセチルグルコサミン転移酵素5B組換え抗体。
- 請求項1~3のいずれか一項に記載の抗体又は請求項4に記載の組換え抗体の断片であって、β1,6-N-アセチルグルコサミン転移酵素5Bを特異的に認識する活性を有する上皮性卵巣癌判定用抗体断片。
- 請求項2に記載の抗体を産生するハイブリドーマ。
- 国際受領番号がFERM ABP-11496である、請求項6に記載のハイブリドーマ。
- 国際受領番号がFERM ABP-11497である、請求項6に記載のハイブリドーマ。
- 国際受領番号がFERM ABP-11498である、請求項6に記載のハイブリドーマ。
- 国際受領番号がFERM ABP-11499である、請求項6に記載のハイブリドーマ。
- 被験者由来の試料中に存在するβ1,6-N-アセチルグルコサミン転移酵素5Bポリペプチド断片を定量的及び/又は定性的に検出し、その検出結果に基づいて該被験者における上皮性卵巣癌の罹患の有無を判定する上皮性卵巣癌判定方法。
- 前記β1,6-N-アセチルグルコサミン転移酵素5Bポリペプチド断片の定量検出結果においてβ1,6-N-アセチルグルコサミン転移酵素5Bポリペプチド断片の定量値が所定の値以上であった場合、その被験者は上皮性卵巣癌に罹患している可能性が高いと判定する、請求項11に記載の上皮性卵巣癌判定方法。
- 前記β1,6-N-アセチルグルコサミン転移酵素5Bポリペプチド断片が配列番号1に示されるアミノ酸配列からなるポリペプチドの全部又は一部である、請求項11又は12に記載の上皮性卵巣癌判定方法。
- β1,6-N-アセチルグルコサミン転移酵素5Bポリペプチド断片を請求項1~3のいずれか一項に記載の抗体、請求項4に記載の組換え抗体及び請求項5に記載の抗体断片からなる群より選択される少なくとも1つの抗体、組換え抗体及び/又は抗体断片を用いて検出する、請求項11~13のいずれか一項に記載の上皮性卵巣癌判定方法。
- β1,6-N-アセチルグルコサミン転移酵素5Bポリペプチド断片上の異なるエピトープを認識する2つの抗体、組換え抗体及び/又は抗体断片を用いる、請求項14に記載の上皮性卵巣癌判定方法。
- 前記試料が、体液、腹腔洗浄液又は組織である、請求項11~15のいずれか一項に記載の上皮性卵巣癌判定方法。
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EP12817890.2A EP2738250B1 (en) | 2011-07-26 | 2012-07-26 | Anti-beta1,6-N-acetylglucosaminyltransferase 5B antibody for detecting epithelial ovarian cancer and method for diagnosing epithelial ovarian cancer |
US14/234,871 US10247733B2 (en) | 2011-07-26 | 2012-07-26 | Antibody for detecting epithelial ovarian cancer marker and method for diagnosing epithelial ovarian cancer |
JP2013525755A JP5857334B2 (ja) | 2011-07-26 | 2012-07-26 | 上皮性卵巣癌マーカー検出用抗体及び上皮性卵巣癌判定方法 |
CN201280037168.9A CN103842503A (zh) | 2011-07-26 | 2012-07-26 | 上皮性卵巢癌标志物检测用抗体和上皮性卵巢癌判定方法 |
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EP2738250B1 (en) | 2017-11-15 |
JPWO2013015367A1 (ja) | 2015-02-23 |
US10247733B2 (en) | 2019-04-02 |
EP2738250A4 (en) | 2015-04-08 |
JP5857334B2 (ja) | 2016-02-10 |
US20140242607A1 (en) | 2014-08-28 |
CN103842503A (zh) | 2014-06-04 |
EP2738250A1 (en) | 2014-06-04 |
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