Anti-norovirus antibodies

Abstract

Disclosed is an anti-norovirus antibody that responds to noroviruses of a number of genotypes and enables comprehensive detection of noroviruses. This anti-norovirus antibody or an antigen-binding fragment thereof undergoes an antigen-antibody reaction with each of peptides respectively having the amino acid sequences represented by SEQ ID NO: 1 and SEQ ID NO: 2. Provided are: the novel anti-norovirus antibody that binds broadly to noroviruses and enables specific and high-sensitive detection of a wide range of human noroviruses; and a norovirus immunoassay method and a norovirus immunoassay instrument using the same.

Description

Technical Field

[0001] The present invention relates to an anti-norovirus antibody, an immunoassay method for norovirus using the same, and an immunoassay instrument.

Background Art

[0002] Norovirus infects humans orally, multiplies in the upper part of the small intestine from the duodenum, and causes infectious gastroenteritis. It causes the shedding of small intestinal epithelial cells near the duodenum, leading to symptoms such as vomiting, diarrhea, and abdominal pain. The incubation period from infection to onset is 12 hours to 72 hours (average 1 to 2 days), and the virus excretion in feces continues for about 1 to 3 weeks even after the symptoms subside, and excretion exceeding 7 weeks has also been reported. Approximately 70% of the reported food poisoning patients are norovirus infections.

[0003] Norovirus is a non-enveloped virus with a genome of plus single-stranded RNA of about 7,500 bases. There are three protein-coding regions (ORFs) in the norovirus genome. It has been reported that ORF1 is a non-structural protein involved in virus replication, ORF2 is a capsid structural protein (VP1), and ORF3 is a minor structural protein (VP2). Also, norovirus is classified into five groups, namely genogroups I to V (GI to GV), based on the similarity of the capsid gene sequence. Among these, GI, GII, and GIV are the main strains causing human infections. In particular, genogroup I (GI) and genogroup II (GII) are rich in genetic diversity, and various viruses with different evolutionary lines have been detected from human-derived samples. It is said that genogroup I can be classified into 9 or more genotypes, and genogroup II can be classified into 22 or more genotypes.

[0004] The detection of norovirus is carried out by detecting the capsid structural protein using an enzyme immunoassay (EIA) method (see Non-Patent Document 1) or an immunochromatography method (see Non-Patent Document 2) using an antibody. Therefore, in order to accurately detect norovirus antigen, an antibody that reacts with all genotypes is required.

[0005] However, antibodies that recognize and react to the common region of the antigen are not readily available. Until now, reagents have been prepared by combining multiple antibodies against norovirus antigen peptides or fragments thereof that have a specific amino acid sequence (see, for example, Patent Document 1), and different genotypes of norovirus have been detected accordingly.

[0006] For example, in an investigation to obtain an antibody that commonly reacts with noroviruses of genogroup GII, it was reported that an antibody that binds to a specific site in the protruding region of the capsid of noroviruses belonging to GII broadly binds to noroviruses of GII and specifically detects almost all noroviruses of the genotypes (GII / 1 to GII / 17) belonging to GII (see Patent Document 2).

[0007] However, norovirus is a highly mutable virus, and the protruding region exposed on the surface of the capsid undergoes many mutations. Even if antibodies that react with a wide range of genotypes can be temporarily produced by performing an antigen-antibody reaction on the protruding region, there is a problem that they will no longer be able to react when mutant strains emerge.

[0008] Therefore, there was a need to create antibodies that could simultaneously detect multiple noroviruses with different genotypes.

[0009] On the other hand, Non-Patent Document 3 describes a monoclonal antibody that reacts with the shell region of the norovirus capsid. [Prior art documents] [Patent Documents]

[0010] [Patent Document 1] Special Publication No. 2009-542715 [Patent Document 2] International Publication WO13 / 039165 [Non-patent literature]

[0011] [Non-Patent Document 1] "Evaluation of an improved Norovirus Antigen Detection EIA Kit," Monthly Journal of Medicine and Pharmacy, Vol. 61, No. 1, Pages 93-98 (January 25, 2009) [Non-Patent Document 2] "QuickNavi Rapid Diagnostic Agent for Norovirus Antigen - Evaluation of Norovirus," Monthly Journal of Medicine and Pharmacy, Vol. 61, No. 5, pp. 779-785 (May 25, 2009) [Non-Patent Document 3] Gabriel I. Parra et al., PLOS ONE, June 2013, Volume 8, Issue 6, e67592 [Overview of the Initiative] [Problems that the invention aims to solve]

[0012] The present invention relates to providing an anti-norovirus antibody that reacts to many genotypes of norovirus and can detect noroviruses collectively. [Means for solving the problem]

[0013] In view of the above problems, the present invention investigated how to obtain an antibody that reacts commonly with norovirus. Focusing on the shell region, which is an internal structure of the norovirus capsid, rather than the protruding region exposed on the surface, the invention found that an antibody that binds to a specific site in the shell region of the norovirus capsid binds broadly to norovirus and can broadly and specifically detect human norovirus.

[0014] In other words, the present invention provides the following:

[0015] (1) An anti-norovirus antibody or its antigen-binding fragment that reacts with each peptide consisting of the amino acid sequences shown in SEQ ID NO: 1 and SEQ ID NO: 2, respectively. (2) The anti-norovirus antibody or an antigen-binding fragment thereof according to claim 1, which reacts with each peptide consisting of the amino acid sequences shown in SEQ ID NO: 3 and SEQ ID NO: 4, respectively, in an antigen-antibody reaction. (3) The anti-norovirus antibody or an antigen-binding fragment thereof according to (1) or (2), wherein the anti-norovirus antibody is a monoclonal antibody. (4) An immunoassay method for norovirus, which utilizes an antigen-antibody reaction between norovirus in a sample and the anti-norovirus antibody or an antigen-binding fragment thereof according to any one of (1) to (3). (5) An immunoassay instrument for norovirus, which contains the anti-norovirus antibody or an antigen-binding fragment thereof according to any one of (1) to (3). [Advantages of the Invention]

[0016] According to the present invention, there are provided a novel anti-norovirus antibody that binds broadly to norovirus and can detect human norovirus specifically and highly sensitively, an immunoassay method for norovirus using the same, and an immunoassay instrument. [Modes for Carrying Out the Invention]

[0017] The anti-norovirus antibody of the present invention is an antibody that reacts with each peptide consisting of the amino acid sequences shown in MMMASKDAPPSMDGASGAGQLVP (SEQ ID NO: 1) and MKMASNDAAPSNDGAAGLVPE (SEQ ID NO: 2) in an antigen-antibody reaction, and binds to an epitope present in the shell region of the capsid structural protein of norovirus. From the commonality of the amino acid sequences shown in SEQ ID NO: 1 and SEQ ID NO: 2, it is considered that an epitope exists in MMMASKDAPPSMDGASG (SEQ ID NO: 3) and MKMASNDAAPSNDGAAG (SEQ ID NO: 4). This region is different from the epitope of the monoclonal antibody described in Non-Patent Document 3.

[0018] The capsid structural protein (VP1) of norovirus is known to consist of a shell region (S domain) and a protruding region (P domain). The S domain is thought to be responsible for the assembly of VP1. On the other hand, the P domain is further divided into P1 and P2 subdomains. The P1 subdomain interacts with the S domain and enhances the physical stability of the capsid. The P2 subdomain is located on the outermost surface of the virus particle and has been reported to be a target of neutralizing antibodies in murine norovirus.

[0019] The anti-norovirus antibody of the present invention can be of any required type, such as IgG, IgA, IgY, IgD, IgM, IgE, or a part of one or more of them, for example, heavy chain, light chain, Fc or F(ab) part.

[0020] The anti-norovirus antibody used in the present invention can be obtained as a polyclonal or monoclonal antibody using known means. Monoclonal antibodies derived from mammals include those produced by hybridomas and those produced by hosts transformed with an expression vector containing an antibody gene by genetic engineering techniques.

[0021] Anti-norovirus monoclonal antibody-producing hybridomas can be produced using basically known techniques as follows: Recombinant norovirus-like hollow particles (VLPs) are used as sensitizing antigens, and immunized according to a standard immunization method. The resulting immune cells are fused with known parent cells using a standard cell fusion method, and monoclonal antibody-producing cells are screened using a standard screening method. From the obtained monoclonal antibodies, monoclonal antibodies that react with each peptide consisting of the amino acid sequences shown in SEQ ID NO: 1 and SEQ ID NO: 2, respectively, can be produced. Polyclonal antibodies can also be produced by immunizing animals such as mice, rats, and hamsters with at least one of the peptides consisting of the amino acid sequences shown in SEQ ID NO: 1 and SEQ ID NO: 2, either as is or immobilized on a commonly used carrier, and recovering the polyclonal antibodies from their serum.

[0022] Recombinant norovirus VLPs can be obtained by inserting the gene sequence of the norovirus capsid into a transfer plasmid vector, simultaneously transfecting Sf9 cells with baculovirus DNA and the aforementioned plasmid, utilizing homologous recombination to produce and propagate recombinant viruses to obtain seed viruses, and then purifying the target recombinant virus VLP from the cells or culture supernatant by known methods after protein expression in Tn5 cells. Recombinant norovirus VLPs themselves are well known and are widely used for purposes such as the creation of anti-norovirus antibodies.

[0023] While there are no particular limitations on the mammals that can be immunized with the sensitizing antigen, it is preferable to select them considering their compatibility with the parent cells used for cell fusion. Generally, rodents such as mice, rats, and hamsters are used.

[0024] Immunizing animals with sensitizing antigens is carried out according to known methods. For example, it is done by injecting the sensitizing antigen into the peritoneal cavity or subcutaneously of mammals. Specifically, the sensitizing antigen is diluted and suspended in an appropriate amount of PBS (Phosphate-Buffered Saline) or physiological saline, and if desired, an appropriate amount of a common adjuvant, such as Freund's complete adjuvant, is mixed in. After emulsification, it is administered subcutaneously, intradermally, or into the peritoneal cavity of the animal for initial stimulation, and the same procedure is repeated as needed. The dosage of the antigen is determined appropriately depending on the route of administration and the animal species, but a typical dosage of about 10 μg to 1 mg per dose is preferred. After immunization in this manner and confirmation that the desired antibody level has risen in the serum, polyclonal antibodies can be obtained by collecting blood from the mammal and purifying the serum components. When purifying the serum components, affinity columns immobilized with the sensitizing antigen can be used.

[0025] Furthermore, when producing monoclonal antibodies, immune cells are extracted from mammals with elevated antibody levels, and cell fusion is performed. Splenocytes are particularly preferred immune cells for cell fusion.

[0026] The mammalian myeloma cells used as the other parent cells to be fused with the aforementioned immune cells can be any of the already known cell lines, such as P3X63, NS-1, MPC-11, SP2 / 0, etc., as appropriate.

[0027] The aforementioned cell fusion of immune cells and myeloma cells can be carried out by known methods, such as the method of Kohler et al. (Kohler et al., Nature, vol, 256, p495-497 (1975)). Specifically, in the presence of cell fusion promoters such as polyethylene glycol (PEG with an average molecular weight of 1000-6000, 30-60% concentration) and Sendai virus (HVJ), and optionally with the addition of auxiliary agents such as dimethyl sulfoxide, immune cells and myeloma cells are mixed in a nutrient culture medium such as RPMI1640 culture medium or MEM culture medium to form fused cells (hybridomas).

[0028] Hybridomas formed by fusion are cultured for 1 to 7 days in a selective medium such as a medium containing hypoxanthine, thymidine, and aminopterin (HAT medium), and then separated from unfused cells. The resulting hybridomas are further selected based on the antibodies they produce. The selected hybridomas are monocloned according to known limiting dilution methods and established as monoclonal antibody-producing hybridomas.

[0029] Known methods can be used to detect the activity of antibodies produced by hybridomas. Examples include ELISA, agglutination tests, and radioimmunoassays.

[0030] To obtain monoclonal antibodies from the resulting hybridomas, methods such as culturing the hybridomas according to standard procedures and obtaining the antibodies as the culture supernatant, or administering the hybridomas to compatible mammals to allow them to grow and obtaining the antibodies as ascites fluid, are employed.

[0031] Antibodies can be purified using known purification methods such as salting-out, gel filtration, ion exchange chromatography, or affinity chromatography.

[0032] By applying the anti-norovirus antibody of the present invention to any immunoassay method, norovirus in a sample can be specifically measured and detected.

[0033] Immunoassay methods themselves are well known, and the immunoassay of the present invention can employ any known immunoassay method except that it uses the anti-norovirus antibody or its antigen-binding fragment of the present invention described above as the antibody or its antigen-binding fragment. Therefore, the immunoassay method is not particularly limited, and any known immunoassay method such as the sandwich method, immunoaggregation method, or competitive method can be employed. Among these, the sandwich method using an anti-norovirus antibody and a labeled anti-norovirus antibody is preferred, and the method using an immobilized anti-norovirus antibody and a labeled anti-norovirus antibody is even more preferred.

[0034] For immobilizing anti-norovirus antibodies, insoluble supports such as polystyrene plates, latex particles, magnetic particles, glass fiber membranes, nylon membranes, nitrocellulose membranes, and cellulose acetate membranes are preferred. Methods for antibody immobilization are well known.

[0035] Furthermore, as labeled anti-norovirus antibodies, known labeling agents, for example, radioisotopes (e.g., 32 P, 35 S, 3 You can use H), enzymes (e.g., peroxidase, alkaline phosphatase, luciferase), proteins (e.g., avidin), low molecular weight compounds (e.g., biotin), fluorescent substances (e.g., FITC), chemiluminescent substances (e.g., acridinium), latex particles (e.g., colored latex particles, fluorescent latex particles), metals (e.g., precious metals such as gold, silver, and platinum), colloidal particles, carbon atoms, etc.

[0036] The detection of norovirus in a sample is performed by reacting the norovirus in the sample with immobilized anti-norovirus antibodies. In the sandwich method, the sample-containing solution is reacted with the immobilized anti-norovirus antibodies, followed by the reaction with the labeled antibody, or the immobilized anti-norovirus antibodies and the labeled antibody are reacted simultaneously. After the reaction is complete, the amount of norovirus in the sample can be measured by measuring the amount of labeling in the complex formed by the norovirus, immobilized anti-norovirus antibodies, and labeled antibody. The amount of labeling can be measured by means appropriate to the type of label. For example, if an enzyme or avidin is used as the label, the substrate is added after the reaction and the enzyme activity is measured. If a fluorescent substance (including fluorescent latex particles) or a chemiluminescent substance is used as the label, the signal is measured under conditions where quenching does not occur. For colored latex particles, metal colloid particles, and carbon particles, the signal is measured visually or by reflected light.

[0037] Among the immunoassay methods described above, ELISA and immunochromatography are more preferred.

[0038] The immunoassay instrument using the anti-norovirus antibody of the present invention includes the immobilized anti-norovirus antibody of the present invention. In addition to the immobilized anti-norovirus antibody, the instrument may also be in the form of a kit consisting of, for example, a sample diluent, a labeled anti-norovirus antibody, a reaction substrate, etc. [Examples]

[0039] Example 1: Acquisition of anti-norovirus monoclonal antibody Norovirus-like hollow particles (VLPs) prepared by a conventional method were immunized to BALB / c mice. After housing the mice for a certain period, the spleens were removed and fused with mouse myeloma cells using the method of Kohler et al. (Kohler et al., Nature, vol, 256, p495-497 (1975)). The resulting fused cells (hybridomas) were maintained in a 37°C incubator, and the reactivity of antibodies produced against norovirus was examined using the culture supernatant. VLPs were diluted to 0.1 μg / mL with 140 mM NaCl, 2.7 mM KCl, 10 mM Na2HPO4, 1.8 mM KH2PO4, pH 7.3 (hereinafter abbreviated as PBS). Diluted VLPs were added to the wells of a plastic microtiter plate (Nunc-Immuno Module F8 Maxisorp Surface plate, trade name, manufactured by Nalgen Nunc International) at a rate of 100 μL per well of VLPs / PBS, pH 7.3 solution. The VLPs were immobilized on the microtiter plate under conditions of 4°C for 12 hours. After 12 hours, the VLPs / PBS solution remaining in the wells was removed by decantation. Then, PBS and 0.05% (v / v) Tween20 (hereinafter abbreviated as PBS-T, Tween is a trade name) were added to the wells of the microtiter plate at a rate of 200 μL / well, and the PBS-T was removed by decantation. This washing process was repeated a total of three times.

[0040] Subsequently, 200 μL / well of 1% PerfectBlock (product name, blocking agent manufactured by Funakoshi Co., Ltd.) / PBS pH 7.3 was added, and the VLP-immobilized microtiter plates were blocked in the wells under conditions of 4°C for 12 hours. After 12 hours, the plates were stored at 4°C. To confirm the reactivity of the anti-norovirus monoclonal antibody in the culture supernatant, 100 μL / well of the culture supernatant was added to the VLP-immobilized microtiter plates, and the plates were heated at 37°C for 1 hour. After that, the culture supernatant that had been added to the wells was removed by decantation, 200 μL / well of PBS-T was added, and the PBS-T was removed by decantation, and the wells were washed. This washing process was performed a total of three times.

[0041] Subsequently, 100 μl / well (10,000-fold dilution) of Peroxidase-Conjugated Goat Anti-Mouse Immunoglobulins (manufactured by Agilent Technologies) (hereinafter referred to as enzyme-labeled antibody) was added to each well, and the mixture was incubated at 37°C for 1 hour. The enzyme-labeled antibody was then removed from the well by decantation, 200 μL / well of PBS-T was added, and the PBS-T was removed by decantation, followed by washing of the well. This washing process was repeated a total of three times. Next, 100 μL / well of 3,3',5,5'-T-tetramethylbenzidine (hereinafter abbreviated as TMB) solution was added to each well as the peroxidase enzyme reaction substrate solution, and the mixture was incubated at 25°C for 30 minutes in the dark. Immediately thereafter, 100 μL / well of 313 mM H2SO4 solution was added to stop the enzyme reaction.

[0042] Subsequently, the absorbance of this well was measured, and the value obtained by subtracting the absorbance at 630 nm from the absorbance at 450 nm was used as an indicator for evaluating reactivity. (Josephy PD, Mason RP et al. (1982) J. Biol. Chem. 257, 3669-3675). Cell purification (monoclonalization) was performed while confirming the antibody activity of the supernatant.

[0043] As a result, we obtained cell lines that produce anti-norovirus monoclonal antibodies, as shown in Table 1.

[0044] The acquired cell line was intraperitoneally administered to BALB / c mice treated with Bristane, and antibody-containing ascites fluid was collected approximately two weeks later. IgG was purified from the obtained ascites fluid using affinity chromatography with a protein A column to obtain purified anti-norovirus shell region antibody (SMoAb).

[0045] Example 2: Confirmation of anti-norovirus antibody epitopes For the anti-norovirus shell region antibody (SMoAb) prepared in Example 1, the amino acid sequence common to the norovirus gene group was identified. Based on the identified amino acid sequence, peptide synthesis was performed to produce a peptide containing the identified amino acid sequence. The prepared peptide was diluted to 0.3 μg / mL with PBS. The diluted peptide was added to the wells of a plastic microtiter plate (Nunc-Immuno Module F8 Maxisorp Surface plate, trade name, Nalgen Nunc International) at a rate of 100 μL per well of norovirus peptide / PBS, pH 7.3 solution, and the norovirus peptide was immobilized on the microtiter plate under conditions of 4°C for 12 hours. After 12 hours, the norovirus peptide / PBS solution remaining in the wells was removed by decantation, and PBS-T was added to the wells of the microtiter plate at a rate of 200 μL / well, and PBS-T was removed by decantation. This washing process was repeated a total of three times.

[0046] Subsequently, 200 μL / well of 1% PerfectBlock (product name, blocking agent manufactured by Funakoshi Co., Ltd.) / PBS pH 7.3 was added, and the wells of the peptide-immobilized microtiter plate were blocked under conditions of 4°C for 12 hours. After 12 hours, the plates were stored at 4°C. To confirm the reactivity of the anti-norovirus monoclonal antibody, 100 μL / well of 1 μg / mL anti-norovirus monoclonal antibody was added to the norovirus peptide-immobilized microtiter plate, and the plate was heated at 37°C for 1 hour. After that, the antibody solution that had been added to the wells was removed by decantation, 200 μL / well of PBS-T was added, and the PBS-T was removed by decantation, and the wells were washed. This washing process was performed a total of three times.

[0047] Next, 100 μl / well (10,000-fold dilution) of enzyme-labeled antibody was added to each well, and the mixture was incubated at 37°C for 1 hour. The enzyme-labeled antibody was then removed from the well by decantation, 200 μL / well of PBS-T was added, and the PBS-T was removed by decantation, followed by washing of the well. This washing process was repeated a total of three times. Then, 100 μL / well of TMB solution was added to each well as the peroxidase enzyme reaction substrate solution, and the mixture was incubated at 25°C for 30 minutes in the dark. Immediately afterward, 100 μL / well of 313 mM H2SO4 solution was added to stop the enzymatic reaction.

[0048] Subsequently, the absorbance of the well was measured, and the value obtained by subtracting the absorbance at 630 nm from the absorbance at 450 nm was used as an indicator for evaluating reactivity (Josephy PD, Mason RP et al. (1982) J. Biol. Chem. 257, 3669-3675). The SMoAb2 clone obtained in Example 1 and the anti-norovirus polyclonal antibody (PoAb) were reacted with peptides on a microtiter plate, and the reaction was confirmed using enzyme-labeled antibody and peroxidase enzyme reaction substrate solution. The amino acid sequences of the peptides in which the reaction was confirmed are shown in Table 1.

[0049] [Table 1]

[0050] The SoMb antibody of the present invention is thought to recognize MMMASKDAPPSMDGASG (SEQ ID NO: 3) and MKMASNDAAPSNDGAAG (SEQ ID NO: 4), which contain many common sequences of No. 1 and No. 8.

[0051] Example 3: Reactivity of anti-norovirus monoclonal antibody in immunochromatography (IC) 1. Immobilization of anti-norovirus antibodies onto nitrocellulose membranes Monoclonal antibodies that react to the capsid overhang region of norovirus GI (GIPMoAb) and monoclonal antibodies that react to the capsid overhang region of norovirus GII (GIIPMoAb) were diluted with purified water to a concentration of 1.0 mg / mL. Anti-mouse IgG antibody was also prepared and applied linearly at a rate of 1 μL / cm to a nitrocellulose membrane backed with PET film to create test lines. Anti-mouse globulin antibody was applied to the control lines in the same manner as above. In this example, this is referred to as an antibody-immobilized membrane.

[0052] 2. Immobilization of anti-norovirus antibodies onto colored polystyrene particles The anti-norovirus shell region antibody (SMoAb) prepared in Example 1 was diluted with purified water to a concentration of 0.5 mg / ml. Colored polystyrene particles were added to this solution to a concentration of 0.1%, and after stirring, carbodiimide was added to a concentration of 1%, and the mixture was stirred again. The supernatant was removed by centrifugation, and the mixture was resuspended in 50 mM Tris (pH 9.0) and 3.0% BSA to obtain anti-norovirus antibody-conjugated colored polystyrene particles. In this example, these are referred to as antibody-immobilized particles.

[0053] 3. Preparation of test specimens The antibody-immobilized membrane was bonded to other components (backing sheet, absorbent band, sample pad), cut into 5 mm wide strips, and used as norovirus test pieces. These are referred to as test pieces in this example.

[0054] 4. Immunoassay 100 μL of a sample suspension containing arbitrarily diluted norovirus VLPs and antibody-immobilized particles was added dropwise to each test specimen, and the specimen was left to stand for 15 minutes.

[0055] A result of + was determined when color development was visually confirmed at the application sites of both the anti-mouse IgG antibody and the anti-norovirus antibody. A result of - was determined when color development was visually confirmed only at the application site of the anti-mouse IgG antibody, and not at the application site of the anti-norovirus antibody. Furthermore, if color development was not visually confirmed at the application site of the anti-mouse IgG antibody, it was determined to be invalid. In addition, the intensity of the color development of the line was indicated as +++>++>+.

[0056] The results of the test specimens of the present invention were compared with those of conventional test specimens using monoclonal antibodies that react to the protruding region of the norovirus capsid.

[0057] [Table 2]

[0058] Table 2 shows that the test specimens of the present invention reacted to all of the GI gene groups tested, compared to conventional products. Furthermore, they reacted more strongly than conventional products, indicating a higher binding affinity of antibodies to norovirus antigens and enabling more sensitive detection of norovirus.

Claims

1. An anti-norovirus monoclonal antibody or its antigen-binding fragment that reacts with each peptide consisting of the amino acid sequences shown in SEQ ID NO: 3 and SEQ ID NO: 4, respectively.

2. An immunoassay method for norovirus, utilizing an antigen-antibody reaction between norovirus in a sample and the anti-norovirus monoclonal antibody or its antigen-binding fragment described in claim 1.

3. An immunoassay device for norovirus comprising the anti-norovirus monoclonal antibody or an antigen-binding fragment thereof as described in claim 1.

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