Cat AGP antibody or its variant, or its functional fragment and use

Abstract

The present invention discloses a cat AGP antibody or a variant thereof, or a functional fragment thereof, wherein the cat AGP antibody or a variant thereof, or a functional fragment thereof is AGP-mAb3, AGP-mAb4 or AGP-mAb5. The present invention also provides a coding gene, a recombinant vector, a host cell, a preparation method, a composition, a use and a kit. The present invention has a high sample compliance rate and a wide detection linearity for cat AGP detection, and reduces the detection cost.

Description

Technical Field

[0001] The present invention relates to the technical field of immunology, and more specifically, to a cat AGP antibody or its variant, or its functional fragment and use. Background Art

[0002] Acute phase proteins (APPs) and cytokines are two biomarkers that are closely associated with inflammation. These proteins are essential for maintaining homeostasis, promoting tissue repair, and eliminating potential causes of disorders, such as infection, trauma, and tumors. It is believed that APPs are synthesized in response to proinflammatory cytokines, such as IL-1, IL-6, and tumor necrosis factor alpha (TNF-α), primarily in the liver. Each species also has its own unique major, secondary, and minor APPs. The major positive APPs in cats include serum amyloid A (SAA) and alpha-1 acid glycoprotein (AGP). α1-Acid glycoprotein (AGP) is an acute phase responder protein and a serum mucin-like protein present in the serum. It is a glycoprotein that, as the major positive APP, is mainly synthesized by hepatocytes and released into the blood when an APR occurs.

[0003] AGP is an important indicator test for feline infectious peritonitis (FIP), especially in Europe. GIORI et al. conducted a study on the specificity and sensitivity of multiple tests in 12 cats. Among them, 33.33% of cats were diagnosed as negative for FIP by histopathology and immunohistochemistry, and 66.66% of cats were diagnosed as positive for FIP by histopathology and immunohistochemistry. However, when FIP is highly suspected and cannot be confirmed by clinical pathology, an elevated AGP concentration can support the diagnosis of FIP.

[0004] Furthermore, AGP is a useful biomarker for severity and response to treatment of inflammatory and infectious diseases in veterinary medicine. AGP concentrations in clinically healthy cats and cats with tumors were 519.9 mg / L (range = 400−721 mg / L) and 1621.6 mg / L (range = 400−3000 mg / L), respectively. Median AGP concentrations were 1568.6 mg / L (range = 400−3000 mg / L) and 1779.4 mg / L (range = 442.5−3000 mg / L) in cats with primary tumors and radiographically suspected metastases; in cats with carcinomas, sarcomas, and lymphomas, the concentrations were 1734.2 mg / L (range = 400−3000 mg / L), 1299.4 mg / L (range = 496.8−1779.4 mg / L), and 2592.4 mg / L (range = 442.5−3000 mg / L), respectively.

[0005] Therefore, detecting the AGP concentration is crucial to determine the overall health of cats. Currently, ELISA kits are often used in clinical practice, but the time and money costs are too high. Therefore, it is necessary to design a technical solution that can overcome the above defects. Summary of the invention

[0006] An object of the present invention is to provide a cat AGP antibody or its variant, or its functional fragment and use thereof, which is used for cat AGP detection with a higher sample compliance rate and a wider detection linearity, and reduces the detection cost.

[0007] In order to achieve these objects and other advantages of the present invention, the present invention provides a cat AGP antibody or a variant thereof, or a functional fragment thereof, wherein the cat AGP antibody or a variant thereof, or a functional fragment thereof comprises AGP-mAb3, AGP-mAb4 or AGP-mAb5; the AGP-mAb3 comprises a heavy chain variable region CDR1 as shown in SEQ ID NO:1, a heavy chain variable region CDR2 as shown in SEQ ID NO:2, and a heavy chain variable region CDR3 as shown in SEQ ID NO:3; the AGP-mAb3 comprises a light chain variable region CDR1 as shown in SEQ ID NO:4, a light chain variable region CDR2 with a sequence of YAS, and a light chain variable region CDR3 as shown in SEQ ID NO:5; the AGP-mAb4 comprises a heavy chain variable region CDR1 as shown in SEQ ID NO:6, a heavy chain variable region CDR2 as shown in SEQ ID NO:7, and a heavy chain variable region CDR3 as shown in SEQ ID NO:8; the AGP-mAb4 comprises a heavy chain variable region CDR1 as shown in SEQ ID NO:6, a heavy chain variable region CDR2 as shown in SEQ ID NO:7, and a heavy chain variable region CDR3 as shown in SEQ ID NO:8; NO:9, a light chain variable region CDR1 with a sequence of RNS, and a light chain variable region CDR3 as shown in SEQ ID NO:10; the AGP-mAb5 includes a heavy chain variable region CDR1 as shown in SEQ ID NO:11, a heavy chain variable region CDR2 as shown in SEQ ID NO:12, and a heavy chain variable region CDR3 as shown in SEQ ID NO:13; the AGP-mAb5 includes a light chain variable region CDR1 as shown in SEQ ID NO:14, a light chain variable region CDR2 with a sequence of IAS, and a light chain variable region CDR3 as shown in SEQ ID NO:15.

[0008] Further, the AGP-mAb3 includes a heavy chain variable region as shown in SEQ ID NO:16, and a light chain variable region as shown in SEQ ID NO:17; the AGP-mAb4 includes a heavy chain variable region as shown in SEQ ID NO:18, and a light chain variable region as shown in SEQ ID NO:19; the AGP-mAb5 includes a heavy chain variable region as shown in SEQ ID NO:20, and a light chain variable region as shown in SEQ ID NO:21.

[0009] The present invention also provides a gene encoding the cat AGP antibody or its variant, or its functional fragment as described in claim 1.

[0010] The present invention also provides a recombinant vector.

[0011] The present invention also provides a host cell.

[0012] The present invention also provides a method for preparing the antibody or its antigen-binding portion, comprising: S1: culturing the host cell; and S2: recovering the antibody or its antigen-binding portion from the host cell or the culture of the host cell.

[0013] The present invention also provides a composition comprising two or three of the AGP-mAb3, the AGP-mAb4, and the AGP-mAb5.

[0014] The present invention also provides the use of cat AGP antibody or its variant, or its functional fragment or composition for detecting cat AGP.

[0015] The present invention also provides a kit, comprising the cat AGP antibody or its variant, or its functional fragment.

[0016] The present invention has at least the following beneficial effects:

[0017] The cat AGP antibody or its variant, or its functional fragment includes AGP-mAb3, AGP-mAb4 and AGP-mAb5, which can be used to detect cat AGP and prepare a kit for detecting cat AGP, and has a higher sample compliance rate and a wider detection linearity, and reduces the detection cost compared with the ELISA kit.

[0018] Other advantages, objectives and features of the present invention will be embodied in part through the following description, and in part will be understood by those skilled in the art through study and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a calibration curve of a cat AGP assay kit prepared using a cat AGP monoclonal antibody according to one embodiment of the present application.

[0020] Figure 2 This is the sample compliance rate of the immunoturbidimetric platform of the cat AGP antigen determination kit in one embodiment of the present application. DETAILED DESCRIPTION

[0021] The present invention is further described in detail below in conjunction with embodiments so that those skilled in the art can implement the invention with reference to the description.

[0022] It should be understood that the terms such as “having”, “including” and “comprising” used herein do not exclude the existence or addition of one or more other elements or combinations thereof.

[0023] The embodiments of the present application provide cat AGP antibodies or variants thereof, or functional fragments thereof, wherein the cat AGP antibodies or variants thereof, or functional fragments thereof include AGP-mAb3, AGP-mAb4 or AGP-mAb5;

[0024] The AGP-mAb3 comprises a heavy chain variable region CDR1 as shown in SEQ ID NO:1, a heavy chain variable region CDR2 as shown in SEQ ID NO:2, and a heavy chain variable region CDR3 as shown in SEQ ID NO:3; the AGP-mAb3 comprises a light chain variable region CDR1 as shown in SEQ ID NO:4, a light chain variable region CDR2 with a sequence of YAS, and a light chain variable region CDR3 as shown in SEQ ID NO:5; specifically, the antibody AGP-mAb3 is composed of a heavy chain and a paired light chain; the sequences of the heavy chain CDR1, CDR2 and CDR3 of the antibody AGP-mAb3 are "GFTISSYG", "IWSDGVT" and "ARNWYDGTSHGYDL" in sequence, and the sequences of the light chain CDR1, CDR2 and CDR3 are "ESVYTMNR", "YAS" and "QGGFYDSGATFT" in sequence;

[0025] The AGP-mAb4 comprises a heavy chain variable region CDR1 as shown in SEQ ID NO:6, a heavy chain variable region CDR2 as shown in SEQ ID NO:7, and a heavy chain variable region CDR3 as shown in SEQ ID NO:8; the AGP-mAb4 comprises a light chain variable region CDR1 as shown in SEQ ID NO:9, a light chain variable region CDR2 with a sequence of RNS, and a light chain variable region CDR3 as shown in SEQ ID NO:10; specifically, the antibody AGP-mAb4 is composed of a heavy chain and a paired light chain; the sequences of CDR1, CDR2 and CDR3 of the heavy chain of AGP-mAb4 are "GFSLSSYG", "ISSDGGT" and "ARGNDNYTWNGFNL" in sequence, and the sequences of CDR1, CDR2 and CDR3 of the light chain are "ESISGY", "RNS" and "QPGYATTLT" in sequence;

[0026] The AGP-mAb5 comprises a heavy chain variable region CDR1 as shown in SEQ ID NO:11, a heavy chain variable region CDR2 as shown in SEQ ID NO:12, and a heavy chain variable region CDR3 as shown in SEQ ID NO:13; the AGP-mAb5 comprises a light chain variable region CDR1 as shown in SEQ ID NO:14, a light chain variable region CDR2 with a sequence of IAS, and a light chain variable region CDR3 as shown in SEQ ID NO:15; specifically, the antibody AGP-mAb5 consists of a heavy chain and a paired light chain; the sequences of the heavy chain CDR1, CDR2 and CDR3 of AGP-mAb5 are "GFSLSNFA", "INIVGEST" and "ARFFYQDYSDGDAFDL" in sequence, and the sequences of the light chain CDR1, CDR2 and CDR3 are "EDINYG", "IAS" and "QSTYQTSFNTA" in sequence;

[0027] The functional fragments of this embodiment include antigen binding portions or fragments;

[0028] In this embodiment, the antigen binding portion is selected from: Fab fragment, Fab' fragment, F(ab')2 fragment, Fv fragment, scFv fragment;

[0029] The antibodies AGP-mAb3, AGP-mAb4 or AGP-mAb5 in this embodiment may be monoclonal antibodies;

[0030] Without substantially affecting the affinity of the antibody, this embodiment includes variants with >90% sequence identity, such as 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%;

[0031] The sequence of the cat AGP in this embodiment can be the sequence shown in SEQ ID NO: 22, that is, QSPECANLTATPITNATLDQLSGKWFYIASAFRNPEFNESSRTIQAAFFYFHINYTEDKILLREYLTIGNQCVYNSSYLNVQRENGSLSKHEFGKEQVGYLLLTKDPRTFMLAFSLKDEQNMGLSFYTDKPQATQEQMREFHEAITCMGMQKSEIMYSDEKQDVCGPLEKEHQEENQKENKGSHHHHHHHH.

[0032] In another embodiment, the AGP-mAb3 comprises a heavy chain variable region as shown in SEQ ID NO: 16 and a light chain variable region as shown in SEQ ID NO: 17; specifically, QSVEESGGRLVTPGTPLTLTCTVSGFTISSYGMSWVRQAPGKGLEWIGCIWSDGVTNHANSMKGRFTISSDNAQNTVFLQMTSLTASDTATYFCARNWYDGTSHGYDLWGPGTLVTVSS and DPVMTQTPASVSGPVGGTVTINCQASESVYTMNRLNWYQQKPGQPPKLLIYYASTLESGVPSRFSGSGSGTDFTLTISGVQCDDAATYYCQGGFYDSGATFTFGGGTEVVVK, respectively;

[0033] The AGP-mAb4 includes a heavy chain variable region as shown in SEQ ID NO: 18 and a light chain variable region as shown in SEQ ID NO: 19; specifically, QSVEESGGRLVTPGTPLTLTCTVSGFSLSSYGMSWVRQAPGKGLEWIGYISSDGGTYYASWAKGRFTISKTSSTTVDLKLTSPTTEDTAAYFCARGNDNYTWNGFNLWGQGTLVTVSS and DVVMTQTPSSLAASVGDTVTITCKASESISGYLSWFQQKPGQRPKLLIYRNSTLASGVSSRFKGSGSGTEFTLTISDLECADAAIHYCQPGYATTLTFGGGTEVVVK, respectively;

[0034] The AGP-mAb5 includes a heavy chain variable region as shown in SEQ ID NO: 20 and a light chain variable region as shown in SEQ ID NO: 21; specifically, QSVKESGGRLVTPGTPLTLTCTASGFSLSNFAMSWVRQAPGKGLEYIGLINIVGESTYYASWAKGRFTISKTSTTVDLKITSPTTEDTATYFCARFFYQDYSDGDAFDLWGQGTLVTVSS and DVVMTQTPSSVSAAVGDTVTIKCQASEDINYGLSWYQQKPGQPPKLLIYIASKLASGVPSRFSGSGSGTQFTLIISDVQCDDAATYYCQSTYQTSFNTAFGAGTKIEIK, respectively.

[0035] The embodiments of the present application also provide genes encoding the feline AGP antibody or its variant, or its functional fragment.

[0036] The embodiments of the present application also provide a recombinant vector, such as a plasmid pTT5 construct.

[0037] The embodiments of the present application also provide host cells; the host cells of this embodiment do not include embryonic stem cells, and can be mammalian cells and insect cells.

[0038] The embodiments of the present application also provide a method for preparing the antibody or antigen-binding portion thereof, comprising:

[0039] S1: culturing the host cell;

[0040] and S2: recovering the antibody or antigen-binding portion thereof from the host cell or a culture of the host cell.

[0041] The embodiments of the present application also provide a composition, including two or three of the AGP-mAb3, the AGP-mAb4, and the AGP-mAb5; it has been verified that the combination of at least two of AGP-mAb3, AGP-mAb4, and AGP-mAb5 can better achieve AGP detection; after testing, the composition of the present application can reduce the detection cost of cat AGP, improve the detection speed, and broaden the detection linear range (see Figure 1 and Figure 2 ).

[0042] The embodiments of the present application also provide the use of cat AGP antibodies or variants thereof, or functional fragments thereof, for detecting cat AGP; optionally, latex-enhanced immunoturbidimetry is used in combination with a standard curve to detect cat AGP.

[0043] The embodiments of the present application also provide a kit, including the cat AGP antibody or its variant, or its functional fragment; optionally, the kit uses latex-enhanced immunoturbidimetry combined with a standard curve to detect cat AGP.

[0044] The following is a description of specific embodiments.

[0045] Example 1: Construction of cat AGP expression vector and protein transient expression

[0046] The first aspect of the present invention discloses an expression system for producing recombinant feline acid glycoprotein (AGP) in mammalian cells, wherein a nucleic acid sequence encoding feline acid glycoprotein is connected to an expression plasmid pTT5 via a HindIII / EcoRI cloning site to obtain an AGP-expressing vector pTT5-AGP-His. The feline AGP protein is expressed using HEK293F host cells.

[0047] Example 2 Obtaining Monoclonal Antibodies Against Cat AGP

[0048] 1.1 Immunization of animals

[0049] 20 ml of 2mg / ml cat AGP antigen was mixed with an equal volume of Freund's complete adjuvant and injected into New Zealand white rabbits at multiple points under the abdomen; after four booster immunizations, the rabbits' immune system was activated, causing B cells to produce antibodies. The serum titer was determined by immunoturbidimetry, and rabbits with high serum titers were selected for another booster immunization, and peripheral blood was collected three days later.

[0050] 1.2 B lymphocyte sorting

[0051] Peripheral blood was collected from rabbits and sorted using DAPI to remove dead cells. Flow cytometry was used to screen single cells to obtain target lymphocytes.

[0052] 1.3 Cloning of the gene encoding rabbit monoclonal antibody

[0053] The sorted single B cells are first cultured in vitro in 96-well plates for 5 to 10 plates, and then the cell culture supernatant is screened by ELISA or FACS and other pre-intervention tests. The cultured B cell supernatant is used to identify positive clones by antigen-coated ELISA. The cells of the positive clones are collected and lysed, and RNA is extracted and reverse transcribed into cDNA. The variable region genes (VH and VL) of the light and heavy chains of rabbit monoclonal antibodies are amplified from the cDNA of the corresponding positive clones by PCR, and the sequences are sequenced to determine the sequences.

[0054] Positive clone screening and epitope identification

[0055] ELISA reaction was used to screen three clones of monoclonal hybridoma cells that can secrete antibodies that bind to cat AGP antigen. The epitope was identified by sandwich method, and AGP-mAb3 antibody was captured and fixed to the surface of the ELISA plate as the primary antibody. Then the cat AGP antigen was injected and bound to the AGP-mAb3 antibody. Subsequently, HRP-labeled AGP-mAb4 or AGP-mAb5 antibody was injected as the secondary antibody. The secondary antibody either binds to the cat AGP antigen to produce a "sandwich" binding, or is blocked by the primary antibody and does not bind to the cat AGP antigen. The results show that the secondary antibody (AGP-mAb4 or AGP-mAb5) can bind to the cat AGP antigen in the presence of the primary antibody (AGP-mAb3), so they have different epitopes; similarly, the results of using AGP-mAb4 antibody as the primary antibody and AGP-mAb5 as the secondary antibody show that they have different epitopes; therefore, the three antibodies have different bins.

[0056] Example 3: Construction of anti-cat AGP monoclonal antibody expression vector

[0057] This embodiment provides a monoclonal antibody that can specifically bind to three different epitopes of cat AGP protein at the same time. The light chain and heavy chain encoding genes of AGP-mAb3 are connected to the expression plasmid pTT5 through the HindIII / EcoRI cloning site to obtain monoclonal antibody expression vectors pTT5-AGP-mAb3-LC and pTT5-AGP-mAb3-HC; the same method is used to obtain pTT5-AGP-mAb4-LC and pTT5-AGP-mAb4-HC; pTT5-AGP-mAb5-LC and pTT5-AGP-mAb5-HC.

[0058] Example 4: Preparation of anti-cat AGP monoclonal antibodies

[0059] HEK293F host cells were used to express feline AGP monoclonal antibodies AGP-mAb3, AGP-mAb4 and AGP-mAb5.

[0060] Dilute the cell density to 2×106 cells / ml, place the shake flask in a 5% CO2 constant temperature shaker, and start transfection after constant temperature shaking and culture at 37℃ and 120rpm for 10 minutes. Prepare two 50ml sterile centrifuge tubes, add 10ml KPM and 100μg of sterile light chain and heavy chain plasmids to one of them, and gently blow and mix; take another centrifuge tube, add 10ml KPM and 1mlTA-293 transfection reagent, and gently blow and mix; transfer all the liquid in the centrifuge tube containing the transfection reagent to the centrifuge tube containing the plasmid, and gently blow and mix; let it stand at room temperature for 10 minutes to prepare the plasmid-vector complex; remove the cells from the constant temperature shaker, add the prepared plasmid-vector complex while shaking, and put it back in the CO2 constant temperature shaker for shaking and culture.

[0061] Adding 1.2 ml of 293 cell protein expression enhancer (KE-293) 24 hours after transfection and transient transfection nutrient additives (KT-Feed 50×) can increase the expression level of the product, and the product expression level is measured on the 6th day after transfection.

[0062] Antibody purification

[0063] The cell culture medium was centrifuged at 5000 rpm, the supernatant was collected and filtered with a 0.22 μm filter, then purified by protein A affinity chromatography column, desalted and replaced with buffer, and stored in aliquots.

[0064] Example 5: Calibration curve of cat AGP antigen detection kit

[0065] Calibrator preparation for the cat AGP detection kit: dilute the cat AGP antigen with calibrator buffer and prepare the calibrator concentration points as follows: 0 mg / L, 200 mg / L, 600 mg / L, 1500 mg / L, 3000 mg / L, and 6000 mg / L.

[0066] The detection principle of a cat acid glycoprotein cat AGP assay kit is:

[0067] The kit uses latex enhanced immunoturbidimetry. The basic principle is to cross-link two cat AGP monoclonal antibodies (AGP-mAb3 and AGP-mAb4) to latex particles, and then react with the cat AGP in the sample to be tested to form a large antigen-antibody complex. The turbidity increases, and the cat AGP concentration is proportional to the turbidity formed. At a wavelength of 570nm, the cat AGP antigen content in the sample can be calculated by comparing the detected turbidity with the standard curve. The calibration curve is as follows: Figure 1 The same scheme was used to test the combination of AGP-mAb3 and AGP-mAb5, and the application of AGP-mAb4 and AGP-mAb5, and the calibration results were similar to those of AGP-mAb3 and AGP-mAb4.

[0068] A method of using a cat AGP antigen assay kit is as follows:

[0069] The cat AGP antigen kit was tested with the fully automatic biochemical analyzer 7180 with the following parameters: first add 3µl of sample, then add 180µl of reagent R1, incubate at 37°C for 5 minutes, add 60µl of reagent R2, read the absorbance A1 after 5 minutes, and calculate the absorbance difference △A=A1-A0 (starting value); use the matching calibrator for multi-point calibration, obtain the calibration curve and perform linear fitting, then the sample concentration (in mg / L) can be calculated on the calibration curve through the absorbance difference detected.

[0070] Example 6: Cat AGP Antigen Detection Kit Performance

[0071] As the core raw material of in vitro diagnostic reagents, the performance of antibodies directly affects the quality of in vitro diagnostic reagent products. As one of the most important indicators for verifying the performance of antibody raw materials, the sample compliance rate is the part that in vitro diagnostic reagent companies pay the most attention to when screening raw materials.

[0072] The sample conformity rate can also be called clinical comparative analysis, which reflects the degree of consistency between the measured value of the clinically assigned sample and the theoretical value of the clinically assigned sample by the diagnostic kit. To assess the sample conformity rate of a new antibody raw material, the antibody is usually used as the raw material to prepare an in vitro diagnostic kit (colloidal gold, immunoturbidimetric platform, etc.), and the actual clinical specimens are tested using the kit and the test results are statistically analyzed for comprehensive assessment and evaluation. Through standardized comparative studies, analysis, and summarization of the relationship between the test results of the kit and the theoretical values ​​of clinical samples, the performance of the antibody raw material can be indirectly inferred. The closer the results of the two are, the better the consistency, and the better the performance of the antibody.

[0073] The concentration range of cat AGP samples was 380-6026 mg / L, with a total of 25 cases. A scatter plot was drawn with the measured value as the ordinate and the theoretical value as the abscissa. The linear regression curve y=1.0195x-29.271 was obtained by computer fitting and R 2 , is 0.9985. Figure 2 The sample compliance rate R of the cat AGP antigen detection kit shown 2 >99%. Obviously, the test kit of this embodiment has a higher sample compliance rate and a higher detection linearity. Compared with the ELISA kit, it has a low cost and can meet the budget of most cat-raising families. It can be used for different clinical diagnosis needs.

[0074] The number of equipment and processing scale described here are used to simplify the description of the present invention. The application, modification and variation of the feline AGP antibody or its variant, or its functional fragment and use of the present invention are obvious to those skilled in the art.

[0075] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the implementation modes, and they can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and the illustrations shown and described herein.

Claims

1. A cat AGP antibody or an antigen-binding portion thereof, characterized in that The cat AGP antibody is AGP-mAb3, AGP-mAb4 or AGP-mAb5; The AGP-mAb3 comprises a heavy chain variable region CDR1 as shown in SEQ ID NO: 1, a heavy chain variable region CDR2 as shown in SEQ ID NO: 2, and a heavy chain variable region CDR3 as shown in SEQ ID NO: 3; The AGP-mAb3 comprises a light chain variable region CDR1 as shown in SEQ ID NO:4, a light chain variable region CDR2 with a sequence of YAS, and a light chain variable region CDR3 as shown in SEQ ID NO:5; The AGP-mAb4 comprises a heavy chain variable region CDR1 as shown in SEQ ID NO:6, a heavy chain variable region CDR2 as shown in SEQ ID NO:7, and a heavy chain variable region CDR3 as shown in SEQ ID NO:8; The AGP-mAb4 comprises a light chain variable region CDR1 as shown in SEQ ID NO:9, a light chain variable region CDR2 having a sequence of RNS, and a light chain variable region CDR3 as shown in SEQ ID NO:10; The AGP-mAb5 comprises a heavy chain variable region CDR1 as shown in SEQ ID NO: 11, a heavy chain variable region CDR2 as shown in SEQ ID NO: 12, and a heavy chain variable region CDR3 as shown in SEQ ID NO: 13; The AGP-mAb5 comprises a light chain variable region CDR1 as shown in SEQ ID NO:14, a light chain variable region CDR2 having a sequence of IAS, and a light chain variable region CDR3 as shown in SEQ ID NO:

15.

2. The cat AGP antibody or antigen binding portion thereof as claimed in claim 1, characterized in that The AGP-mAb3 comprises a heavy chain variable region as shown in SEQ ID NO: 16 and a light chain variable region as shown in SEQ ID NO: 17; The AGP-mAb4 comprises a heavy chain variable region as shown in SEQ ID NO: 18 and a light chain variable region as shown in SEQ ID NO: 19; The AGP-mAb5 includes a heavy chain variable region as shown in SEQ ID NO:20 and a light chain variable region as shown in SEQ ID NO:

21.

3. A gene encoding the feline AGP antibody or antigen binding portion thereof according to claim 1.

4. A recombinant vector comprising the gene according to claim 3.

5. A host cell comprising the recombinant vector according to claim 4.

6. A method for preparing a cat AGP antibody or an antigen binding portion thereof as claimed in claim 1, comprising: S1: culturing the host cell according to claim 5; and S2: Recovering the antibody or antigen-binding portion thereof from the host cell or a culture of the host cell.

7. A composition, characterized in that It comprises two or three of the AGP-mAb3, the AGP-mAb4 and the AGP-mAb5 in claim 1.

8. Application of the cat AGP antibody or its antigen binding portion thereof as claimed in claim 1 or the composition as claimed in claim 7 in the preparation of a test kit for detecting cat AGP.

9. A kit, characterized in that The method comprises the cat AGP antibody or antigen-binding portion thereof as described in claim 1 or the composition as described in claim 7.

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