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WO2020077532A1 - 一种基于胎盘样硫酸软骨素a的癌症筛查和早期诊断的试剂方法 - Google Patents

一种基于胎盘样硫酸软骨素a的癌症筛查和早期诊断的试剂方法 Download PDF

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WO2020077532A1
WO2020077532A1 PCT/CN2018/110465 CN2018110465W WO2020077532A1 WO 2020077532 A1 WO2020077532 A1 WO 2020077532A1 CN 2018110465 W CN2018110465 W CN 2018110465W WO 2020077532 A1 WO2020077532 A1 WO 2020077532A1
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elisa
tumor
antibody
detection
cancer
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PCT/CN2018/110465
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English (en)
French (fr)
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范秀军
张居作
张键
代小勇
张保珍
汪宝蓓
陈指龙
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中国科学院深圳先进技术研究院
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Priority to PCT/CN2018/110465 priority Critical patent/WO2020077532A1/zh
Publication of WO2020077532A1 publication Critical patent/WO2020077532A1/zh

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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07K—PEPTIDES
    • C07K14/00—Peptides having more than 20 amino acids; Gastrins; Somatostatins; Melanotropins; Derivatives thereof
    • C07K14/435—Peptides having more than 20 amino acids; Gastrins; Somatostatins; Melanotropins; Derivatives thereof from animals; from humans
    • C07K14/44—Peptides having more than 20 amino acids; Gastrins; Somatostatins; Melanotropins; Derivatives thereof from animals; from humans from protozoa
    • C07K14/445—Plasmodium
    • C—CHEMISTRY; METALLURGY
    • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
    • C12Q—MEASURING OR TESTING PROCESSES INVOLVING ENZYMES, NUCLEIC ACIDS OR MICROORGANISMS; COMPOSITIONS OR TEST PAPERS THEREFOR; PROCESSES OF PREPARING SUCH COMPOSITIONS; CONDITION-RESPONSIVE CONTROL IN MICROBIOLOGICAL OR ENZYMOLOGICAL PROCESSES
    • C12Q1/00—Measuring or testing processes involving enzymes, nucleic acids or microorganisms; Compositions therefor; Processes of preparing such compositions
    • C12Q1/68—Measuring or testing processes involving enzymes, nucleic acids or microorganisms; Compositions therefor; Processes of preparing such compositions involving nucleic acids
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
    • Y02A50/30—Against vector-borne diseases, e.g. mosquito-borne, fly-borne, tick-borne or waterborne diseases whose impact is exacerbated by climate change

Definitions

  • the invention relates to the field of biotechnology detection, in particular to an ELISA method and kit for cancer screening and early diagnosis based on placenta-like chondroitin sulfate A.
  • Cancer is a serious public health problem worldwide, resulting from the uncontrollable abnormal growth and metastasis of cancer cells.
  • the current cancer screening and early diagnosis are scientific problems that have not been overcome. When cancer cases are found, they usually enter the middle and late stages. At this time, cancer cells have extensively metastasized or grown wildly. It is difficult for ordinary drugs to suppress cancer cells. Growth, chemotherapy has become the main way. Most chemotherapy drugs eliminate or inhibit cancer cells while inhibiting the growth and renewal of normal cells, making cancer an incurable disease.
  • the early stage of cancer may be the window period for treatment, so there is an urgent need to explore a more effective method for cancer screening and early diagnosis.
  • Enzyme-linked immunosorbent assay (enzyme-linked immuno-sorbent assay, ELISA) was started in 1975, when it was used to detect Trichinella antibodies, used to diagnose trichinosis [6] . Due to the characteristics of high sensitivity, good specificity, simple operation and high throughput of ELISA method [7,8] , it has been widely used in related diseases such as bacteria [9] , viruses [7] and parasites [10] . Screening, diagnosis and immunological monitoring. However, such a method is rarely applied and popularized in cancer screening and early diagnosis. The main reason is the lack of a specific expression of cancer cells and the widespread presence of biological markers in various cancer tissues. Thing.
  • chondroitin sulfate A is a characteristic glycosaminoglycan with a characteristic disaccharide unit [11] in cancer tissues.
  • Medium specific expression interestingly, it is widely expressed in a variety of cancer tissues, may play a key role in the development of cancer, and has a positive correlation with the degree of malignancy of the tumor [12] .
  • pl-CSA was originally discovered as a receptor for the accumulation of red blood cells of the Plasmodium in the placental villi, and it can specifically bind to the surface antigen VAR2CSA of the red blood cells of Plasmodium.
  • the combination of VAR2CSA and pl-CSA has a high affinity and specificity.
  • the affinity of the smallest binding unit is about 15Nm [13] , making VAR2CSA a specific capture protein for pl-CSA to purify pl -CSA, or it can be used in other areas, but lacks the development and application of reagents and methods in this area. Immunization with purified pl-CSA, preparation of antibodies, and further establishment of immunological monitoring methods will be widely and very promising for the application of sun exposure and early diagnosis of cancer.
  • the ELISA method has the characteristics of high sensitivity, high specificity, simple operation and high throughput [7,8] , and has been widely used in bacteria [9] , viruses [7] and parasites [10] and other related diseases. Screening, diagnosis and immunological monitoring. However, such a method is rarely used in cancer screening and early diagnosis. The main reason is the lack of a cancer cell-specific expression and widespread biomarkers in a variety of cancer tissues.
  • the present invention selects pl-CSA, a marker specifically expressed in cancer tissues and widely expressed in various cancer tissues, but whether it can be released into biological fluids, such as culture supernatant or serum, is now It is not reported in the technology, and it is unclear whether an ELISA detection method can be developed to detect the content of pl-CSA released in the cancer cells themselves and biological fluids, so as to determine the presence of cancer cells, and to achieve the purpose of cancer screening and early diagnosis.
  • Torre LA Bray F, Siegel RL, Ferray J, Lortet-Tieulent J, Jemal A: Global cancer statistics, 2012. CA: a cancer, journal for clinicians 2015, 65 (2): 87-108.
  • pl-CSA can be detected in biological fluids such as blood, and verified that the occurrence of tumors in the subject is confirmed by analyzing the level of pl-CSA , Development or rehabilitation.
  • pl-CSA-trapped Plasmodium infected erythrocyte surface antigen-binding peptides and pl-CSA antibodies are used as detection reagents to detect the subject. It was confirmed that pl-CSA and its antibodies can be used for in vitro detection of body fluids for early tumor diagnosis and tumor development monitoring.
  • the first aspect of the present invention provides an ELISA kit for detecting tumors, which includes a capture protein for detecting placenta-like chondroitin sulfate A (pl-CSA).
  • the ELISA kit includes a stationary phase carrier.
  • the stationary phase carrier is preferably a 96-well microplate, a microcup, a nanorod, a nanoparticle, and other biocompatible materials, as long as it can capture The protein is fixed on the surface of the stationary phase without destroying the biological activity.
  • the capture protein is selected from the minimum binding peptide of the plasmodium-infected erythrocyte surface antigen (VAR2CSA, rVAR2), and its sequence is shown in SEQ ID No. 1.
  • the method is for non-diagnostic and therapeutic use.
  • the kit further includes a detection antibody;
  • the detection antibody is an antibody to placenta-like chondroitin sulfate A, preferably a monoclonal antibody, polyclonal antibody, polyclonal antibody Specific antibodies (eg, bispecific antibodies) and antibody fragments as long as they can display the desired antigen-binding activity.
  • placenta-like chondroitin sulfate A is obtained by the following methods: commercially available, chemical synthesis method, chemical separation and purification method, such as the method in CN201710966913.2.
  • the detection antibody is obtained by immunizing an organism with placenta-like chondroitin sulfate A, obtaining an antibody by a hybridoma method, or obtaining an antibody by a genetic engineering method.
  • the kit further includes an enzyme-labeled antibody, and the enzyme-labeled antibody is an antibody against the enzyme of the detection antibody.
  • the enzyme in the enzyme-labeled antibody is selected from horseradish peroxidase, alkaline phosphatase (ALP), ⁇ -galactase and other enzymes, gold colloid, etc., but not limited to The above markers.
  • the color developing substrate when horseradish peroxidase is used, is selected from 3,3 ', 5,5'-tetramethylbenzidine, o-phenylenediamine, and the like.
  • the color developing substrate is selected from p-nitrophenyl phosphate and the like.
  • ⁇ -galactase as the color developing substrate, it is selected from o-nitrophenyl- ⁇ -D-galactopyranoside and the like.
  • the kit further includes a washing solution, a sample dilution solution, a color developing solution, a stop solution, and a standard control protein.
  • the detection limit of pl-CSA is 310 ng / ml or more, preferably 1 ug / ml or more.
  • the tested samples are cell lysate, cell culture fluid, blood, serum, and plasma.
  • the tumor includes ovarian cancer, liposarcoma, lung cancer, liver cancer, breast cancer, bone marrow cancer, testicular stromal tumor, prostate cancer, pancreatic cancer, cervical cancer, and colon cancer.
  • Another aspect of the present invention provides the use of an antibody that infects the minimal binding peptide of erythrocyte surface antigen and / or pl-CSA in the preparation of a reagent for detecting tumor screening, early diagnosis of tumor, tumor progression, or tumor rehabilitation.
  • the sequence of the smallest binding peptide of the erythrocyte surface antigen is shown in SEQ ID No. 1.
  • the reagents described in the present invention are reagents for enzyme immunoassay (ELISA), reagents for chemiluminescence enzyme immunoassay (CLEIA), reagents for chemiluminescence immunoassay (CLIA), reagents for fluorescent antibody method (FAT), fluorescence Reagents for enzyme immunoassay (FEIA), reagents for electrochemiluminescence immunoassay (ECLIA), reagents for radioimmunoassay (RIA), reagents for immunochromatography, reagents for agglutination, reagents for competition, colloid Gold test strips, nano-detection reagents, colloidal reagents, ELISA reagents, etc.
  • the enzyme immunoassay is selected from ELISA direct method, ELISA indirect method, ELISA sandwich method, preferably ELISA sandwich method.
  • the reagent described in the present invention is used for the detection of blood or body fluids of a subject.
  • the pl-CSA is placenta-like chondroitin sulfate A.
  • Another aspect of the present invention provides the use of the aforementioned ELISA kit for tumor detection as a detection reagent or tool for tumor screening, early diagnosis of tumor, tumor progression, or tumor rehabilitation.
  • Another aspect of the present invention provides an ELISA method for detecting placenta-like chondroitin sulfate A, in which the smallest binding peptide of the erythrocyte surface antigen (VAR2CSA, rVAR2) infected by Plasmodium is used as the capture protein, and the erythrocyte surface antigen (VAR2CSA) infected by Plasmodium , RVAR2) is shown in SEQ ID No. 1.
  • the method is for non-diagnostic and therapeutic use.
  • the ELISA is a direct method ELISA, an indirect method ELISA, or a sandwich method ELISA.
  • a further aspect of the present invention provides a method for detection of tumor screening, early diagnosis of tumor, tumor progression, or tumor rehabilitation based on placental-like chondroitin sulfate A, the method is a sequence of the smallest binding peptide that infects an erythrocyte surface antigen
  • a detection reagent a method for detecting pl-CSA in a subject in vitro, the sequence of the surface antigen infected with erythrocytes is shown in SEQ ID No. 1.
  • the in vitro detection is performed by enzyme immunoassay (ELISA) method, chemiluminescence enzyme immunoassay (CLEIA), chemiluminescence immunoassay (CLIA), fluorescent antibody method (FAT), luciferase immunoassay (FEIA), electrochemiluminescence immunoassay (ECLIA), radioimmunoassay (RIA), immunochromatography, agglutination, competition, colloidal gold test strip, nano-detection reagent colloid method, but, and Not limited to these methods.
  • the enzyme immunoassay is selected from ELISA direct method, ELISA indirect method, ELISA sandwich method, preferably ELISA sandwich method.
  • the samples tested in vitro are the cell lysate, cell culture fluid, blood, serum, and plasma of the subject.
  • the aforementioned ELISA kit is used for detection.
  • the detection antibody is an antibody or antibody fragment to be detected.
  • the enzyme-labeled antibody is a secondary antibody with a labeled detection antibody.
  • the detection method or reagent for tumor screening, early diagnosis of tumor, tumor progression or tumor rehabilitation means that placenta-like chondroitin sulfate A is detected in the test sample and the test sample is tested The person suffered from a tumor.
  • pl-CSA can be detected in a variety of body fluids, which provides a basis for qualitative or quantitative in vitro biological detection of pl-CSA.
  • the present invention verifies that the pl-CSA can detect the tumor condition of the subject through in vitro detection, and provides a new method for early tumor diagnosis.
  • the method of the invention is simple, with low detection limit, good repeatability and high specificity.
  • Figure 1 is a technical schematic diagram of the present invention.
  • Figure 2 shows the results of sensitivity and repeatability tests. Among them A is the sensitivity experiment result, B is the repetitive experiment result.
  • Fig. 3 shows the application of the method of the present invention to detect the level of pl-CSA expressed by tumor cells.
  • Figure 4 shows the verification test results of model mice and clinical case samples. Among them, A is the experimental result of model rats, and B is the experimental result of clinical cases.
  • pl-CSA-BP Chemically synthesize the smallest binding peptide EDVKDINFDTKEKFLAGCLIVSFHEGKC of VAR2CSA, named pl-CSA-BP as the capture protein of ELISA method.
  • pl-CSA can be prepared by a commercially available or chemical method.
  • the present invention adopts the laboratory's prior patent method to prepare pl-CAS.
  • preparation method please refer to the preparation in the application number: 201710966913.2. details as follows,
  • the chromatographic purification method is to load the crude product of placenta-like chondroitin sulfate A or its derivative onto an affinity chromatography column, and wash with a washing solution until no impurities flow out, and then elute with an eluent and Collect pure placenta-like chondroitin sulfate A or its derivatives.
  • the sequence of the recombinant Plasmodium infection erythrocyte surface antigen protein is shown in SEQ ID No. 2.
  • the potency was determined by indirect non-competitive ELISA method. Dissolve 1 ⁇ g / ml pl-CSA in the coating buffer and add it to the microplate, 100 ⁇ L / well, overnight at 4 ° C. After washing the plate three times with PBST, 200ml of 2% BSA blocking solution per well was reacted at 37 ° C for 1 hour. Wash the plate three times with PBST and add 100 ⁇ L of antibody serum dilution solution to each well. After reacting at 37 ° C for 1 hour, the plate was washed three times with PBST, 100 ⁇ L of goat anti-mouse enzyme-labeled secondary antibody was added to each well, and reacted at 37 ° C for 1 hour. Wash the plate six times with PBST, and add substrate coloring solution to react for 15 minutes. Add 50 ⁇ L 2M sulfuric acid to stop the reaction. The absorbance was measured at 450nm.
  • Monoclonal antibodies were prepared using mouse ascites. Incomplete Freund's adjuvant was injected intraperitoneally into mice, 0.4m / L. After 3 days, each mouse was intraperitoneally injected with hybridoma cells. After 7 to 12 days, ascites was drawn when the mice's abdomen swelled significantly. Centrifuge at 3000 rpm / min for 10 minutes, discard the upper fat, collect the clear ascites in the middle, and store it frozen at -20 ° C until use.
  • Monoclonal antibodies are purified by saturated ammonium sulfate method and Protein A method.
  • Saturated ammonium sulfate method take 10m of treated ascites into a beaker and slowly add 5.0m of saturated ammonium sulfate solution under magnetic stirring; after stirring for 30min; centrifuge at 10000r / min for 15min; discard The supernatant and the precipitate were resuspended with 1/3 saturation ammonium sulfate solution. After stirring for 30min, 10000r / min and centrifuged for 15min; the supernatant was discarded and the precipitate was dissolved in 1.5mL of pure water and loaded into dialysis Bag, dialyze for 24h, remove salt ions, and change water every 6h. After dialysis, vacuum freeze-dry and store at -20 °C.
  • Protein A method Dilute 5m mouse ascites with PBS solution to 50m L, filter with 0.45 ⁇ m filter membrane and put on Protein A column. Flow rate is 1m / L / min; wash 20mL with PBS solution, flow rate is 1m / L; elute with pH4.0 citrate buffer, flow rate is 1m / L, collect elution peak, use pure water Wash 20mL, then rinse with 0.3% Na3N3PBS 5mL and save, the flow rate is 2mL / min, the column is placed at 4 °C and stored. The eluent was loaded into a dialysis bag, dialyzed for 24h, to remove salt ions, and changed water every 6h. After dialysis, vacuum freeze-dry and store at -20 °C.
  • the purity of monoclonal antibodies was determined by SDS-PAGE gel electrophoresis. The steps are: inject 10% separating glue into the glass interlayer, and the upper part is sealed with pure water. After the separating glue is polymerized, pour out pure water, inject 5% concentrated glue, and insert a spotting comb. The monoclonal antibody was added to an equal volume of 2 ⁇ SDS-PAGE sample treatment solution to a final concentration of 5 ⁇ g / m L, 100 ° C water bath for 5 min. After cooling, it was set aside. After adding 10 ⁇ L of sample, the initial voltage was 80V, and then the voltage was separated by 120V. When the bromophenol blue indicator reached the bottom edge, the electrophoresis was stopped. Then peel off the gel and stain, after 0.5 h, decolorize with decolorizing solution overnight, and take a picture with the gel imager.
  • Pl-CSA and its structural analogs CSB and CSC were used as competitive inhibitors.
  • First dilute the competitor take 50 ⁇ L of each and mix with the same amount of antibody, add it to the coated and sealed ELISA plate, and incubate at 37 °C for 1h. The rest steps are the same as the indirect non-competitive ELISA method.
  • the concentration of the corresponding competitive inhibitor at 50% inhibition rate of each curve was calculated as IC50.
  • the cross-reaction rate of the two was measured by the percentage of the IC50 value of pl-CSA and the IC50 value of other structural analogs.
  • Pl-CSA antibody dilution factor is determined by matrix method, that is, 96-well microplate is coated with pl-CSA-BP, the concentration is greater than 5 ⁇ g / ml, preferably the concentration is 20 ⁇ g / ml, diluted in 50mM carbonate buffer at pH9.6 , 200 ⁇ l per well, incubate overnight at 4 °C, wash the plate three times with PBST. 2% BAS was blocked at 37 ° C for 2 hours.
  • a series of concentration gradient pl-CSA including 3.91 ⁇ g / ml, 7.81 ⁇ g / ml, 15.63 ⁇ g / ml, 31.25 ⁇ g / m, 62.50 ⁇ g / m, 125.00 ⁇ g / ml, 250.00 ⁇ g / ml, and 500.00 ⁇ g / ml , 12 replicate wells of each concentration, incubate at 37 ° C for 2 hours, and wash the plate 3 times with PBST for 5 minutes each time.
  • pl-CSA antibodies including 1: 100,1: 1,000,1: 10,1,100,000, 3 replicate wells per concentration, incubate at 37 ° C for 2 hours, set non-immunized mouse serum as negative control, same as PBST Wash the plate 3 times. After reacting at 37 ° C for 1 hour, the plate was washed three times with PBST, 100 ⁇ L of goat anti-mouse enzyme secondary antibody (1: 10,000) was added to each well, and the reaction was performed at 37 ° C for 1 hour. Wash the plate six times with PBST, add TMB substrate color developing solution and react for 15 minutes. Add 50 ⁇ L 2M sulfuric acid to stop the reaction. The absorbance was measured at 450nm.
  • the P / N value of the experimental antibody should be higher than the national standard (the national standard is ⁇ 2.1), and the optimal dilution factor for this test is 1: 1000.
  • pl-CSA-BP 20 ⁇ g / ml
  • the preferred concentration of pl-CSA-BP (20 ⁇ g / ml) was diluted in 50 mM carbonate buffer at pH 9.6, coated with 200 ⁇ l per well in 96-well microplates, incubated at 4 ° C overnight, and washed with PBST three times. 2% BAS was blocked at 37 ° C for 2 hours.
  • a series of concentration gradient pl-CSA including 0.31,0.61 ⁇ g / ml, 1.22 ⁇ g / ml, 2.44 ⁇ g / ml, 4.88 ⁇ g / ml, 9.77 ⁇ g / ml, 19.53 ⁇ g / ml, 39.06 ⁇ g / ml, 78.13 ⁇ g / ml, 156.25 ⁇ g / ml, 312.50 ⁇ g / ml, 625.00 ⁇ g / ml, 1 250.00 ⁇ g / ml, 2 500.00 ⁇ g / ml, and 5 000.00 ⁇ g / ml, 3 replicate wells per concentration, incubate at 37 °C for 2 hours, Wash the plate 3 times with PBST for 5 minutes each time.
  • Pl-CSA antibody is optimally diluted 1: 1 000, and non-immunized mouse serum is set as a negative control. Incubate at 37 ° C for 2 hours and wash the plate 3 times as above with PBST. After reacting at 37 ° C for 1 hour, the plate was washed three times with PBST, 100 ⁇ L of goat anti-mouse enzyme secondary antibody (1: 10,000) was added to each well, and the reaction was performed at 37 ° C for 1 hour. Wash the plate six times with PBST, add TMB substrate color developing solution and react for 15 minutes. Add 50 ⁇ L 2M sulfuric acid to stop the reaction. The absorbance was measured at 450nm. See Figure 2A for experimental results.
  • the sensitivity of the ELISA detection method of the present invention is 310 ng / ml, and the optimal detection range is 3.91 ⁇ g / ml to 500.00 ⁇ g / ml.
  • the pl-CSA concentration is 3.91 ⁇ g / ml, 7.81 ⁇ g / ml, 15.63 ⁇ g / ml, 31.25 ⁇ g / ml, 62.50 ⁇ g / ml, 125.00 ⁇ g / ml, 250.00 ⁇ g / ml , 500.00 ⁇ g / ml, for the repeatability verification of the standard series concentration. See Figure 2B for experimental results.
  • the most suitable detection range is 1.00 ⁇ g / ml to 500.00 ⁇ g / ml, which has good reproducibility.
  • the CSB (500 ⁇ g / ml) and CSC (500 ⁇ g / ml) were detected, and the reliable value of the experiment was P / N ⁇ 2.1.
  • the OD450nm of the two is similar to the negative serum detection value, P / N is approximately equal to 1, and does not have a substantial antagonistic effect on the specific binding of pl-CSA.
  • the experimental results confirm that the method of the present invention has good specificity.
  • DMEM / DF12 medium was supplemented with 10% FBS and 37 ° C 5% CO2 incubator.
  • the cells grew to a fusion rate of 80-90%, Wash twice with PBS, replace with fresh serum-free medium, continue culturing for 24h, collect the culture supernatant; centrifuge at 1000rpm for 10min, collect the supernatant for detection; culture cells were washed with PBS twice, 0.25% of EDTA-free trypsin digestion and separation Collect the cell suspension, centrifuge at 1000 rpm for 5 min to collect the cells, resuspend the cells in PBS, sonicate at 50% power for 20 sec (ultrasonic 5 sec, stop 5 sec), centrifuge at 1000 rpm for 5 min, collect the supernatant to be the cell lysate Used for testing.
  • the detection method is the same as ELISA repeatability test.
  • pl-CSA expressed by cancer cells can be accurately detected to distinguish normal cells from cancer cells. See Table 1 for specific information. The results are shown in Figure 3. The experimental results confirmed that pl-CSA can be detected in the culture supernatant and lysate of cancer cells, but not in normal cells. This proves that ELISA can be used to identify normal cells and cancer cells, so as to achieve screening and early diagnosis and evaluation of treatment effects using biological fluids or tumor tissue cells.
  • cancer model mouse serum namely ovarian cancer (10 cases) and choriocarcinoma (10 cases), choriocarcinoma cell JEG3 and ovarian cancer cell SKOV3 in DMEM / DF12 medium (supplemented with 10% FBS), 37 °C 5 % CO2 incubator, wait for the cells to grow to 80-90% fusion rate, 0.25% EDTA-free trypsin digestion to separate the cells, collect the cell suspension, centrifuge at 1000 rpm for 5 min to collect the cells, and resuspend the cells in PBS.
  • DMEM / DF12 medium supplemented with 10% FBS
  • FBS fetal bovine serum
  • the present invention selects two types of clinical cancer cases, namely cervical cancer (7 cases) and ovarian cancer (7 cases).
  • Tumor blood samples come from Shenzhen Nanshan Hospital and Peking University Shenzhen Hospital. After passing ethical review and patient ’s informed consent, blood samples It was transported back to the laboratory at 4 ° C, centrifuged at 1000 rpm for 20 minutes, and the supernatant was collected as serum for detection.
  • the ELISA method is used to test and complete the clinical sample application verification. For the experimental results, see Figure 4B. The results can accurately detect pl-CSA in the serum of cancer cases, thereby distinguishing the serum of cancer patients and healthy people.

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Abstract

本发明公开一种基于胎盘样硫酸软骨素A的癌症筛查和早期诊断的试剂和方法，具体公开了一种用于检测肿瘤的ELISA试剂盒，其包括用于与胎盘样硫酸软骨素A(pl-CSA)结合的捕获蛋白，所述的捕获蛋白选自疟原虫感染红细胞表面抗原(VAR2CSA，rVAR2)的最小结合肽段，所述最小结合肽段序列如SEQ ID No.1所示。pl-CSA能够在多种体液中检测到，这为定性或定量在体外生物学检测pl-CSA提供了依据。

Description

一种基于胎盘样硫酸软骨素A的癌症筛查和早期诊断的试剂方法 技术领域
本发明涉及生物技术检测领域，具体涉及一种基于胎盘样硫酸软骨素A的癌症筛查和早期诊断ELISA方法及其试剂盒。
背景技术
癌症是一种全球范围内严重的公共健康问题，源于癌细胞不可控的异常生长和转移。根据国际癌症组织的2012年的统计，每年大约有1410万的新增癌症病例，造成大约有820万病人死亡，且因生活方式的改变呈现逐年增加的趋势，如饮食失衡、缺乏锻炼以及高龄生育等 [1-3]。遗憾的是，目前癌症的筛查、和早期诊断是尚未克服的科学难题，癌症病例被发现时通常已经进入中晚期，此时癌细胞已广泛转移或者疯狂生长，普通的药物很难抑制癌细胞生长，化疗成为了主要的方式，多数的化疗药物在消灭或抑制癌细胞的同时抑制了正常细胞的生长和更新，使得癌症成为了不治之症。癌症的早期可能是治疗的窗口期，因此迫切需要探索一种更有效的癌症筛查和早期诊断的方法。
近期的分子标志物研究为癌症发生机制提供了一种新的视角，如糖胺聚糖 [4]，血管生成素 [5]等。但基于这些生物标志物还缺乏可靠的筛查和诊断方法。酶联免疫吸附试验(enzyme-linked immuno-sorbent assay,ELISA)起始于1975年，当时用于检测旋毛虫抗体，用以诊断旋毛虫病 [6]。由于ELISA方法的敏感性高、特异性好、操作简单、高通量等特点 [7,8]，先已经被广泛用于细菌 [9]、病毒 [7]和寄生虫 [10]等相关疾病的筛查、诊断和免疫学监测。然而这样一种方法却很少在癌症的筛查和早期诊断中得到应用和推广，最主要的原因是缺乏一种癌症细胞特异性性表达，且在多种癌症组织中广泛存在的生物学标志物。
在已经发现癌症标志物中，胎盘样硫酸软骨素A(placental like chondroitin sulfate A,pl-CSA)是一种特征性的糖胺聚糖，具有特征性的二糖单元 [11]，在癌症组织中特异性表达，有趣的是其在多种癌症组织中广泛表达，可能在癌症发展进程中发挥关键作用，与肿瘤的恶性程度呈正相关性 [12]。但pl-CSA最初作为疟原虫感染红细胞在胎盘绒毛间隙聚集的一种受体被发现，能够与疟原虫感染红细胞表面抗原VAR2CSA特异性结合。VAR2CSA与pl-CSA的结合具有高度的亲和性、特异性，最小结合单位的亲和力KD约为15Nm [13]，使得VAR2CSA能成为pl-CSA的一种特异性的捕获蛋白，用以纯化pl-CSA，或者在其他方面得以应用，但缺乏这方面试剂和方法的开发和应用。以纯化的pl-CSA进行免疫，制备抗体，从进一步建 立免疫学监测方法，用于癌症的晒产和早期诊断将具有广泛和非常有前景的应用价值。
ELISA方法具有高度敏感性、高度特异性、操作简单、高通量性等特点 [7,8]，已经被广泛用于细菌 [9]、病毒 [7]和寄生虫 [10]等相关疾病的筛查、诊断和免疫学监测。然而这样一种方法缺很少在癌症的筛查和早期诊断中得到应用，最主要的原因是缺乏一种癌症细胞特异性性表达，且在多种癌症组织中广泛存在的生物学标志物。
本发明针对这一科学难题，选择在癌症组织特异性表达，且在多种癌症组织中广泛性表达的标志物pl-CSA，但其是否能释放进入生物液体，如培养上清或者血清，现有技术中并未报道，不清楚是否可以开发ELISA检测方法，检测癌症细胞本身、以及生物液体中释放的pl-CSA含量，从而确定癌细胞的存在，达到癌症筛查和早期诊断的目的。
参考文献
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发明内容
为了解决早期诊断癌症较难，验证方法少等难题，本发明首次证实了在血液等生物液体中能检测到pl-CSA，并且验证了通过分析pl-CSA的水平确证受试者患肿瘤的发生、发展或康复情况。本发明采用捕获pl-CSA的疟原虫感染红细胞表面抗原结合肽段及pl-CSA抗体作为检测试剂对受试者进行检测。证实了pl-CSA及其抗体能够通过体液的体外检测，进行早期的肿瘤诊断和肿瘤发展监控。
具体地，本发明第一个方面提供了提供一种用于检测肿瘤的ELISA试剂盒，其包括用于检测胎盘样硫酸软骨素A(pl-CSA)的捕获蛋白。
本发明中的技术方案中，所述ELISA试剂盒包含固定相载体，所述固定相载体优选为96孔微量板、微量杯、纳米棒、纳米粒等生物相容性材料，只要其能够将捕获蛋白固定于固定相表面而不破坏生物活性。
在本发明的技术方案中，所述的捕获蛋白选自疟原虫感染红细胞表面抗原(VAR2CSA，rVAR2)的最小结合肽段，其序列如SEQ ID No.1所示，
EDVKDINFDTKEKFLAGCLIVSFHEGKC SEQ ID No.1。
在上述方法中，所述方法为非诊断和治疗用途。
在本发明的技术方案中，试剂盒中还包括检测抗体；所述的检测抗体为胎盘样硫酸软骨素A的抗体，优选地为胎盘样硫酸软骨素A的单克隆抗体、多克隆抗体、多特异性抗体(例如，双特异性抗体)和抗体片段，只要其能够显示所需的抗原结合活性。
所述的胎盘样硫酸软骨素A通过以下方法获得：市售获得，化学合成方法，化学分离纯 化方法，例如CN201710966913.2中的方法制得。
所述检测抗体通过以胎盘样硫酸软骨素A对生物体进行免疫后获得抗体、通过杂交瘤方法获得抗体或通过基因工程方法获得抗体。
在本发明的技术方案中，试剂盒中还包括酶标抗体，所述酶标抗体为抗检测抗体酶标的抗体。
在本发明的技术方案中，所述的酶标抗体中的酶选自辣根过氧化物酶、碱性磷酸酶(ALP)、β-半乳糖酶等酶、金胶体等，但并不限于上述标记物。
在本发明的技术方案中，在使用辣根过氧化物酶的情况下，作为显色底物选自3，3'，5，5'-四甲基联苯胺、邻苯二胺等。在使用ALP的情况下，作为显色底物选自对硝基苯磷酸酯等。在使用β-半乳糖酶时，作为显色底物，选自邻硝基苯基-β-D-吡喃半乳糖苷等。
在本发明的技术方案中，试剂盒中还包括洗涤液、样品稀释液、显色液、终止液、标准对照蛋白。
在本发明的技术方案中，pl-CSA的检测限为310ng/ml以上，优选为1ug/ml以上。
在本发明的技术方案中，受检测的样品为细胞裂解液、细胞培养液、血液、血清、血浆。
在本发明的技术方案中，所述肿瘤包括卵巢癌、脂肪肉瘤、肺癌、肝癌、乳腺癌、骨髓癌、睾丸间质瘤、前列腺癌、胰腺癌、宫颈癌、结肠癌。
本发明另一个方面提供了感染红细胞表面抗原的最小结合肽段和/或pl-CSA的抗体在制备检测肿瘤筛查、肿瘤早期诊断、肿瘤进展或肿瘤康复的试剂中的用途，所述的感染红细胞表面抗原的最小结合肽段的序列如SEQ ID No.1所示。
本发明中所述的试剂为酶免疫分析(ELISA)用试剂、化学发光酶免疫测定法(CLEIA)用试剂、化学发光免疫测定法(CLIA)用试剂、荧光抗体法(FAT)用试剂、荧光酶免疫测定法(FEIA)用试剂、电化学发光免疫测定法(ECLIA)用试剂、放射免疫测定法(RIA)用试剂、免疫层析法用试剂、凝集法用试剂、竞争法用试剂、胶体金试纸条、纳米检测试剂胶体试剂、ELISA试剂等，但是，并不限于这些方法。在上述技术方案中，所述酶免疫分析选自ELISA直接法、ELISA间接法，ELISA夹心法，优选为ELISA夹心法。
本发明中所述的试剂用于受试者血液或体液的检测。
在本发明的技术方案中，所述的pl-CSA为胎盘样硫酸软骨素A。
本发明另一个方面提供了前述用于检测肿瘤的ELISA试剂盒作为肿瘤筛查、肿瘤早期诊断、肿瘤进展或肿瘤康复的检测试剂或工具的用途。
本发明另一个方面提供了一种ELISA检测胎盘样硫酸软骨素A的方法，其中以疟原虫感染 红细胞表面抗原(VAR2CSA，rVAR2)的最小结合肽段作为捕获蛋白，疟原虫感染红细胞表面抗原(VAR2CSA，rVAR2)的最小结合肽段序列如SEQ ID No.1所示，
EDVKDINFDTKEKFLAGCLIVSFHEGKC SEQ ID No.1。
在上述方法中，所述方法为非诊断和治疗用途。
在上述方法中，所述ELISA为直接法ELISA、间接法ELISA或夹心法ELISA。
本发明再一个方面提供了一种基于胎盘样硫酸软骨素A的肿瘤筛查、肿瘤早期诊断、肿瘤进展或肿瘤康复的检测方法，所述方法为以感染红细胞表面抗原的最小结合肽段的序列作为检测试剂，体外检测受试者体内pl-CSA的方法，所述以感染红细胞表面抗原的序列如SEQ ID No.1所示。
上述方法中，所述的体外检测为以酶免疫分析(ELISA)法、化学发光酶免疫测定法(CLEIA)、化学发光免疫测定法(CLIA)、荧光抗体法(FAT)、荧光酶免疫测定法(FEIA)、电化学发光免疫测定法(ECLIA)、放射免疫测定法(RIA)、免疫层析法、凝集法、竞争法、胶体金试纸条、纳米检测试剂胶体方法进行检测，但是，并不限于这些方法。在上述技术方案中，所述酶免疫分析选自ELISA直接法、ELISA间接法，ELISA夹心法，优选为ELISA夹心法。
上述方法中，体外检测的样品为受试者的细胞裂解液、细胞培养液、血液、血清、血浆。
优选地，采用前述ELISA试剂盒进行检测。
在本发明中，所述检测抗体为与待检测物的抗体或抗体片段。
在本发明中，所述酶标抗体为带有标记的检测抗体的二抗。
在本发明的技术方案中，所述的肿瘤筛查、肿瘤早期诊断、肿瘤进展或肿瘤康复的检测方法或者试剂，是指待测样品中检测到胎盘样硫酸软骨素A则待测样品受试者罹患肿瘤。
有益效果
1)本发明首次发现了pl-CSA能够在多种体液中检测到，这为定性或定量在体外生物学检测pl-CSA提供了依据。
2)本发明验证了通过体外检测pl-CSA能够判断受试者患肿瘤情况，为早期肿瘤诊断提供了新的方法。
3)本发明的方法简单，同时检测限低、重复性好、特异性高。
附图说明
图1为本发明的技术原理图。
图2为灵敏性和重复性检测结果。其中A为灵敏性实验结果，B为重复性实验结果。
图3为应用本发明方法检测肿瘤细胞表达pl-CSA的水平。
图4为模型鼠和临床病例样本验证检测结果。其中A为模型鼠实验结果，B为临床病例实验结果。
具体实施方式
实施例1.ELISA捕获蛋白的准备
化学合成VAR2CSA的最小结合肽段EDVKDINFDTKEKFLAGCLIVSFHEGKC，命名为pl-CSA-BP作为ELISA方法的捕获蛋白。
实施例2.纯化的pl-CSA准备
pl-CSA可以通过市售或化学方法制备，本发明采用本实验室在先专利方法制备pl-CAS。制备方法参见申请号：201710966913.2中的制备。具体如下，
以亲和层析的方法对胎盘样硫酸软骨素A或其衍生物进行层析纯化，其中亲和层析柱材为重组疟原虫感染红细胞表面抗原蛋白与亲和层析基质的偶联物，所述层析纯化的方法为将胎盘样硫酸软骨素A或其衍生物粗品上样于亲和层析柱上，并以洗涤液进行洗涤至没有杂质流出，再以洗脱液进行洗脱并收集胎盘样硫酸软骨素A纯品或其衍生物纯品。所述重组疟原虫感染红细胞表面抗原蛋白的序列如SEQ ID No.2所示。
SEQ ID No.2
Figure PCTCN2018110465-appb-000001
Figure PCTCN2018110465-appb-000002
实施例3.pl-CSA抗体的准备
1)Balb/c小鼠免疫
50μg免疫原pl-CSA溶于200μL PBS溶液，与等体积的完全弗氏佐剂混合，微量抗原乳化装置充分乳化1小时。然后颈背部多点注射六周龄雌性Balb/c小鼠。初次免疫采用弗氏完全佐剂，并重复一次，加强免疫为弗氏不完全佐剂，免疫间隔期为2周，融合前三天腹腔注射100μg pl-CSA免疫原溶于200μL PBS溶液，不加佐剂。第三次免疫后的7天到10天小鼠尾部采血，每只小鼠约15μL，进行效价检测。
2)效价测定
效价测定采用间接非竞争ELISA法。将1μg/ml pl-CSA溶于包被缓冲液中，加入酶标板中，100μL/孔，4℃过夜。PBST洗板三次后，每孔200ml 2％BSA封闭液，37℃反应1小时。PBST洗板三次，每孔加入100μL抗体血清稀释溶液。37℃反应1小时后，PBST洗板三次，每孔加入100μL羊抗鼠酶标二抗，37℃反应1小时。PBST洗板六次，加入底物显色液反应15分钟。加入50μL 2M硫酸终止反应。在450nm下测定吸收值。
3)细胞融合
采集免疫鼠血液，4℃1200rpm离心30分钟，收集血清，此血清既为pl-CSA多克隆抗体。
在无菌状态下，取出抗体血清高效价Balb/c小鼠的脾脏，放入盛有RPMI-1640培养液的匀浆器，将脾脏轻轻研磨，吸出细胞悬液，离心去杂，RPMI-1640培养液洗涤两次。取对数生长的骨髓瘤细胞SP2/0，1200rpm离心5分钟，弃上清，用RPMI-1640培养液混悬细胞后计数，取所需的细胞数。将SP2/0骨髓瘤细胞与脾细胞按1:10比例混合在一起，在50ml离心管内用RPMI-1640培养液洗1次，1200rpm，离心8分钟，弃上清，吸净残留液体，以免影响PEG浓度。轻轻弹击离心管底，使细胞沉淀略加松动。在37℃下，30秒内加入预热的1m L 50％PEG，边加边搅拌。90秒后，缓慢加入预热RPMI-1640培养液终止PEG作用。1200rpm，离心5分钟，弃上清，加入10m L RPMI-1640培养液重悬细胞，与90m L半固体HAT培养液充分混合。采用20m L注射器吸取半固体培养基，转移至6孔细胞培养板，每孔1.5m L，37℃，5％CO 2培养箱培养14天。
4)杂交瘤细胞的筛选
14天后，培养板中长出肉眼可见的白点，每个白点及为一株杂交瘤细胞株。将每个白点及时转移至96孔细胞培养板。倒置显微镜下观察，当细胞即将充满视野时，测定细胞上清。首先采用间接非竞争ELISA法，见2.2.3.2。每孔加100μL细胞上清测定。将阳性孔取出，再做间接竞争ELISA法。将1μg/m L pl-CSA溶于包被缓冲液中，加入酶标板中，100μL/孔，4℃过夜。PBST洗板三次后，每孔200μL 1.5％OVA封闭液，37℃反应1小时。PBST洗板三次，每孔加入50μL细胞上清和50μL PL-CSA标准液。37℃反应1小时后，PBST洗板三次，每孔加入100μL羊抗鼠酶标二抗，37℃反应1小时。PBST洗板六次，加入底物显色液反应15分钟。加入50μL 2M硫酸终止反应。在450nm下测定吸收值，将对pl-CSA有抑制的细胞株筛选出来。
5)单克隆抗体的制备
采用小鼠腹水制备单克隆抗体。不完全弗氏佐剂腹腔注射小鼠，0.4m L/只，3天后每只小鼠腹腔注射杂交瘤细胞，7～12天后，当小鼠腹部膨胀明显时抽取腹水。3000rpm/min离心10分钟，弃去上部脂肪，收集中间澄清腹水，-20℃冻存备用。
6)单克隆抗体的纯化及鉴定
单克隆抗体的纯化采用饱和硫酸铵法和Protein A法纯化。
步骤如下：饱和硫酸铵法：取10m L处理好的小鼠腹水移入烧杯中，在磁力搅拌下，缓慢滴加饱和硫酸铵溶液5.0m L；继续搅拌30min后；10000r/min离心15min；弃去上清液，沉淀物用1/3饱和度硫酸铵溶液重悬，搅拌作用30min后，10000r/min，离心15min；弃去上清液，沉淀物溶于1.5m L纯水中，装入透析袋，透析24h，去除盐离子，每6h换水。透析好后，真空冷冻干燥，-20℃保存备用。
Protein A法：将5m L小鼠腹水用PBS溶液稀释到50m L，0.45μm滤膜过滤后上Protein A柱。流速为1m L/min；用PBS溶液再洗20m L，流速为1m L/min；用p H4.0柠檬酸缓冲液洗脱，流速为1m L/min，收集洗脱峰，用纯水流洗20m L，再用0.3％Na N3PBS冲洗5m L并保存，流速为2m L/min，柱子置于4℃中保存。洗脱液装入透析袋，透析24h，去除盐离子，每6h换水。透析好后，真空冷冻干燥，-20℃保存备用。
单克隆抗体的纯度采用SDS-PAGE凝胶电泳法测定。步骤为：将10％分离胶注入玻璃夹层中，上部用纯水密封，待分离胶聚合后，倒去纯水，注入5％浓缩胶，插入点样梳。将单克隆抗体加入等体积2×SDS-PAGE样品处理液至终浓度为5μg/m L，100℃水浴5 min，冷却后备用。加样10μL后，起始电压80V，然后用120V电压进行分离，待溴苯酚蓝指示剂到达底部边缘时即停止电泳。然后剥胶染色，0.5h后用脱色液过夜脱色，凝胶成像仪拍照。
7)单克隆抗体的特异性测定
将pl-CSA与其结构类似物CSB，CSC作为竞争抑制原。先将竞争原进行梯度稀释，各取50μL与等量抗体混合，加入已经包被并封闭好的ELISA板中，37℃温育1h，其余步骤同间接非竞争ELISA法。以各竞争抑制原浓度为横坐标，以抑制率(各浓度标准竞争抑制原孔OD值与不加竞争抑制原孔OD值的百分比)为纵坐标绘制标准曲线。以各曲线抑制率为50％时对应的竞争抑制原的浓度计为IC50。以pl-CSA的IC50值和其他结构类似物的IC50值比较的百分数来衡量两者的交叉反应率。
实施例4.pl-CSA抗体的最佳稀释倍数
不同批次抗体稀释倍数存在差异，需要每批次检测。此部分选择多克隆抗体和单克隆抗体都可行，优选单克隆抗体。
Pl-CSA抗体稀释倍数的测定采用矩阵法，既96孔微量板包被pl-CSA-BP，浓度为大于5μg/ml，优选浓度20μg/ml，稀释于50mM pH 9.6的碳酸盐缓冲液中，每孔200μl，4℃孵育过夜，PBST洗板三次。2％的BAS 37℃封闭2小时。一系列浓度梯度的pl-CSA，包括3.91μg/ml,7.81μg/ml,15.63μg/ml,31.25μg/m,62.50μg/m,125.00μg/ml,250.00μg/ml,and 500.00μg/ml，每个浓度12个复孔，37℃孵育2小时，PBST洗板3次，每次5分钟。pl-CSA抗体，包括1:100,1:1 000,1:10 000,1:100 000，每个浓度3个复孔，37℃孵育2小时，设非免疫鼠血清为阴性对照，同上PBST洗板3次。37℃反应1小时后，PBST洗板三次，每孔加入100μL羊抗鼠酶标二抗(1:10 000)，37℃反应1小时。PBST洗板六次，加入TMB底物显色液反应15分钟。加入50μL 2M硫酸终止反应。在450nm下测定吸收值。
实验抗体的P/N值应高于国家标准(国家标准为≥2.1)，而本次检测最佳稀释倍数为1:1000。
表1.本批次抗体的最佳稀释倍数检测。
Figure PCTCN2018110465-appb-000003
Figure PCTCN2018110465-appb-000004
实施例5.ELISA灵敏性验证
优选浓度的pl-CSA-BP(20μg/ml)稀释于50mM pH 9.6的碳酸盐缓冲液中，每孔200μl包被96孔微量板，4℃孵育过夜，PBST洗板三次。2％的BAS 37℃封闭2小时。一系列浓度梯度的pl-CSA，包括0.31,0.61μg/ml,1.22μg/ml,2.44μg/ml,4.88μg/ml,9.77μg/ml,19.53μg/ml,39.06μg/ml,78.13μg/ml,156.25μg/ml,312.50μg/ml,625.00μg/ml,1 250.00μg/ml,2 500.00μg/ml,和5 000.00μg/ml，每个浓度3个复孔，37℃孵育2小时，PBST洗板3次，每次5分钟。pl-CSA抗体最优稀释1:1 000，设非免疫鼠血清为阴性对照，37℃孵育2小时，同上PBST洗板3次。37℃反应1小时后，PBST洗板三次，每孔加入100μL羊抗鼠酶标二抗(1:10 000)，37℃反应1小时。PBST洗板六次，加入TMB底物显色液反应15分钟。加入50μL 2M硫酸终止反应。在450nm下测定吸收值。实验结果参见图2A。
本发明ELISA检测方法的灵敏性为310ng/ml，最适检测范围在3.91μg/ml至500.00 μg/ml。
实施例6.ELISA重复性验证
如前述实施例5中的实验步骤，选用pl-CSA浓度为3.91μg/ml,7.81μg/ml,15.63μg/ml,31.25μg/ml,62.50μg/ml,125.00μg/ml,250.00μg/ml,500.00μg/ml，为标准系列浓度进行重复性验证。实验结果参见图2B。
最适检测范围在1.00μg/ml至500.00μg/ml，在此范围内具有较好的重复性。
实施例7.ELISA特异性验证
根据上述实验中的步骤，检测CSB(500μg/ml)和CSC(500μg/ml)，实验可靠值采用P/N≥2.1。利用pl-CSA的同类物CSB和CSC，二者的OD450nm类似于阴性血清检测值，P/N约等于1，且对pl-CSA的特异性结合不具备有实质性的拮抗作用。实验结果证实本发明的方法特异性好。
实施例8针对细胞裂解物和上清液的检测
选择了15种细胞，包括10种癌细胞和4种正常的细胞，DMEM/DF12培养基补充10％的FBS，37℃5％的CO2培养箱，待细胞生长至80-90％的融合率，用PBS洗2次，更换新鲜无血清培养基，继续培养24h，收集培养上清；1000rpm离心10min，收集上清用于检测；培养细胞用PBS洗2次，0.25％的无EDTA胰酶消化分离细胞，收集细胞悬液，1000rpm离心5min收集细胞，细胞重悬于PBS中，冰浴条件50％的功率超声波20sec(超声5sec、停5sec)，1000rpm离心5min，收集上清即为细胞裂解液，用于检测。应用此ELISA方法进行检测，检测方法同ELISA重复性检测。通过研究能够准确检测癌症细胞表达的pl-CSA，从而区分正常细胞和癌症细胞。具体信息参见表1。结果参见图3。实验结果证实癌细胞的培养上清、裂解液中均可以检测到pl-CSA，而正常细胞检测不到。以此证明可以用过ELISA的方法鉴别正常细胞和癌细胞，从而实现利用生物液体或者肿瘤组织细胞进行筛查和早期诊断、以及治疗效果评价。
表1.所选用的细胞
Figure PCTCN2018110465-appb-000005
Figure PCTCN2018110465-appb-000006
实施例9针对动物模型样品的检测
选择2种癌症模型鼠血清，即卵巢癌(10例)和绒癌(10例)，绒癌细胞JEG3和卵巢癌细胞SKOV3在DMEM/DF12培养基中(补充10％的FBS)，37℃5％的CO2培养箱，待细胞生长至80-90％的融合率，0.25％的无EDTA胰酶消化分离细胞，收集细胞悬液，1000rpm离心5min收集细胞，细胞重悬于PBS中。10 6个细胞小鼠尾静脉全身植瘤或者皮下植瘤，每周测定皮下肿瘤组织大小；利用Fluc基因、腹腔注射荧光素、通过小动物成像监测体内肿瘤细胞的生长，肿瘤生长26天后，麻醉眼球采血，处死小鼠。血液1000rpm离心20min，收集上清既为血清，用于检测。通过ELISA方法进行本发明的应用验证，实验方案同重复性验证，实验结果参见图4A，该实验结果说明本发明的方法能准确的检测到癌症模型鼠血清中存在游离的pl-CSA，从而实现区别癌症模型鼠和正常健康鼠血清。
实施例10针对患者样品的检测
本发明选择2种临床癌症病例，既宫颈癌(7例)和卵巢癌(7例)，肿瘤血液样本来自深圳市南山医院和北京大学深圳医院，通过了伦理审查和病人的知情同意，血液样本4℃运回实验室，1000rpm离心20min，收集上清既为血清，用于检测。通过ELISA方法进行检测，完成临床样本应用验证，实验结果参见图4B结果能准确检测出癌症病例血清中的pl-CSA，从而区别癌症病人和健康人群血清。

Claims (13)

  1. 一种用于检测肿瘤的ELISA试剂盒，其包括用于与胎盘样硫酸软骨素A(pl-CSA)结合的捕获蛋白，优选地，所述的捕获蛋白选自疟原虫感染红细胞表面抗原(VAR2CSA，rVAR2)的最小结合肽段，更优选地，所述最小结合肽段序列如SEQ ID No.1所示，
    EDVKDINFDTKEKFLAGCLIVSFHEGKC SEQ ID No.1。
  2. 根据权利要求1所述的ELISA试剂盒，其特征在于，试剂盒中还包括检测抗体；所述的检测抗体为胎盘样硫酸软骨素A的抗体，优选地为胎盘样硫酸软骨素A的单克隆抗体、多克隆抗体、多特异性抗体和抗体片段。
  3. 根据权利要求1-2任一项所述的ELISA试剂盒，其特征在于，试剂盒中还包括酶标抗体，所述酶标抗体为抗检测抗体酶标的抗体；
    优选地，所述的酶标抗体中的酶选自辣根过氧化物酶、碱性磷酸酶(ALP)、β-半乳糖酶、金胶体，
    更优选地，在使用辣根过氧化物酶的情况下，作为显色底物选自3，3'，5，5'-四甲基联苯胺、邻苯二胺；在使用ALP的情况下，作为显色底物选自对硝基苯磷酸酯；在使用β-半乳糖酶时，作为显色底物，选自邻硝基苯基-β-D-吡喃半乳糖苷。
  4. 根据权利要求1-3任一项所述的ELISA试剂盒，其特征在于，试剂盒中还包括洗涤液、样品稀释液、显色液、终止液、标准对照蛋白。
  5. 根据权利要求1-4任一项所述的ELISA试剂盒，其特征在于，最低检测限为310ng/ml以上，优选为1ug/ml以上。
  6. 权利要求1-5任一项所述的ELISA试剂盒作为肿瘤筛查、肿瘤早期诊断、肿瘤进展或肿瘤康复的检测试剂或工具的用途。
  7. 一种检测胎盘样硫酸软骨素A的ELISA方法，其中以疟原虫感染红细胞表面抗原的最小结合肽段作为捕获蛋白，疟原虫感染红细胞表面抗原的最小结合肽段序列如SEQ ID No.1所示，
    EDVKDINFDTKEKFLAGCLIVSFHEGKC SEQ ID No.1；
    优选地，所述ELISA为直接法ELISA、间接法ELISA或夹心法ELISA；
    更优选地，当为夹心法ELISA时以胎盘样硫酸软骨素A抗体为检测抗体。
  8. 感染红细胞表面抗原的最小结合肽段和/或胎盘样硫酸软骨素A的抗体在制备检测受试者罹患肿瘤情况的试剂中的用途，所述的感染红细胞表面抗原的最小结合肽段的序列如SEQ ID No.1所示；
    优选地，受检测的样品为生物体液，
    更优选为细胞裂解液、细胞培养液、血液、血清、血浆；
    所述罹患肿瘤情况包括肿瘤筛查、肿瘤早期诊断、肿瘤进展或肿瘤康复。
  9. 根据权利要求6所述的用途，其特征在于，其中所述的试剂为酶免疫分析用试剂、化学发光酶免疫测定法用试剂、化学发光免疫测定法用试剂、荧光抗体法用试剂、荧光酶免疫测定法用试剂、电化学发光免疫测定法用试剂、放射免疫测定法用试剂、免疫层析法用试剂、凝集法用试剂、竞争法用试剂、胶体金试纸条、纳米检测试剂胶体试剂、ELISA试剂；
    优选地，所述酶免疫分析选自ELISA直接法、ELISA间接法，ELISA夹心法，
    更优选为ELISA夹心法。
  10. 一种基于胎盘样硫酸软骨素A的用于瘤筛查、肿瘤早期诊断、肿瘤进展或肿瘤康复的检测方法，所述方法以胎盘样硫酸软骨素A的特异性结合肽段作为检测试剂，体外检测受试者体内pl-CSA的方法，
    优选地，所述胎盘样硫酸软骨素A的特异性结合肽段为感染红细胞表面抗原的最小结合肽段，其序列如SEQ ID No.1所示。
  11. 根据权利要求10所述的检测方法，其特征在于，所述的体外检测为以酶免疫分析法、化学发光酶免疫测定法、化学发光免疫测定法、荧光抗体法、荧光酶免疫测定法、电化学发光免疫测定法、放射免疫测定法、免疫层析法、凝集法、竞争法、胶体金试纸条、纳米检测试剂胶体方法进行检测，
    优选地，所述酶免疫分析选自ELISA直接法、ELISA间接法，ELISA夹心法，更优选为ELISA夹心法；
    更优选地，采用权利要求1-5任一项所述ELISA试剂盒进行检测。
  12. 根据权利要求10或11所述的检测方法，其特征在于，体外检测的样品为受试者的生物 体液，优选地，生物体液选自细胞裂解液、细胞培养液、血液、血清、血浆。
  13. 根据权利要求8-12任一项所述的用途或方法，其特征在于，所述肿瘤选自卵巢癌、脂肪肉瘤、肺癌、肝癌、乳腺癌、骨髓癌、睾丸间质瘤、前列腺癌、胰腺癌、宫颈癌、结肠癌。
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WO2023148398A1 (en) * 2022-02-07 2023-08-10 Var2 Pharmaceuticals Aps Antibodies and antibody fragments and analogues specific for chondroitin sulfate

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CN102459646A (zh) * 2009-05-15 2012-05-16 环太平洋生物技术有限公司 胃癌的检测标志物
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CN102459646A (zh) * 2009-05-15 2012-05-16 环太平洋生物技术有限公司 胃癌的检测标志物
CN104136041A (zh) * 2012-02-09 2014-11-05 Var2制药有限公司 靶向硫酸软骨素聚糖

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WO2023148398A1 (en) * 2022-02-07 2023-08-10 Var2 Pharmaceuticals Aps Antibodies and antibody fragments and analogues specific for chondroitin sulfate

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