Anti-influenza A virus antibodies, reagents and kits for detecting influenza A virus

Abstract

The present invention discloses an anti-influenza A virus antibody or a reagent and kit for detecting influenza A virus, relating to the field of antibodies. The anti-influenza A virus antibody disclosed in the present invention comprises a heavy chain complementary determining region and a light chain complementary determining region. The antibody provides an important raw material source for the detection of influenza A virus and has good affinity or activity.

Description

Technical Field

[0001] The present invention relates to the field of antibody technology, and in particular to an anti-influenza A virus antibody, a reagent and a kit for detecting influenza A virus. Background Art

[0002] Influenza virus (Flu), also known as influenza virus for short, is a representative species of the Orthomyxoviridae family, which includes human influenza virus, swine influenza virus, equine influenza virus, avian influenza virus, etc. Human influenza virus can be divided into three types: A (A), B (B), and C (C) based on the antigenicity of its nucleoprotein. It is the pathogen of influenza. Influenza virus can cause infection and disease in a variety of animals, including humans, poultry, pigs, horses, and bats. Among them, influenza A virus and influenza B virus are the main ones that can infect humans, mainly causing upper respiratory tract infections, but can also cause lower respiratory tract infections in children and adults, mainly pneumonia. Severe influenza in infants and young children is often accompanied by bronchitis and high fever.

[0003] Influenza A virus (Flu-A) was successfully isolated in 1933. Its antigens are prone to mutation and can be further divided into subtypes such as H1N1, H3N2, H5N1, and H7N9 (H represents the hemagglutinin of the influenza virus, and N represents the neuraminidase of the influenza virus). The severity of influenza A virus infection is related to individual immunity. Typical symptoms include chills, persistent high fever, and headache, accompanied by sore throat, cough, nasal congestion, and generally, systemic symptoms such as body aches and fatigue. Literature reports that the positive detection rate during epidemic periods is 20-40%, while the positive rate during non-epidemic seasons is 2-20%. The persistent spread of influenza A virus can cause significant disruption and pressure on people's health, daily lives, and social public health prevention systems. It has become a major research topic in epidemiology.

[0004] Currently, the main methods for influenza A virus detection on the market include fluorescent PCR, immunoassays, and virus isolation, culture, and identification. Fluorescent PCR uses fluorescent signals during the PCR amplification process to monitor the PCR process in real time for qualitative or quantitative detection. This method is the gold standard for pathogen detection. Immunoassays detect the target protein through specific binding between antigens and antibodies. Common methods for virus isolation and culture include chick embryo inoculation, animal inoculation, and tissue (cell) culture, followed by observation and analysis of the results. While fluorescent PCR offers good sensitivity and specificity, it has a short detection window and requires high standards for personnel, specialized training, and specialized equipment in qualified laboratories. Virus isolation, culture, and identification testing are time-consuming, require high environmental standards, pose a high risk of infection to the operator, and have poor culture results, resulting in very limited application. Immunoassays target antigens or antibodies in samples, offer rapid detection and high accuracy, and require less demanding laboratory and operator requirements. They are widely used for primary screening in hospital laboratories, disease control laboratories, and other areas. They play a crucial role in initial influenza A detection, successful outbreak control, and treatment guidance in hospitals and communities.

[0005] Currently, immunoassays for influenza A on the market primarily include enzyme-linked immunosorbent assay (ELISA) and colloidal gold immunochromatography. All of these immunoassays require antibodies against influenza A. Therefore, those skilled in the art have a strong demand for high-performance anti-influenza A antibodies. Summary of the Invention

[0006] The present application provides an antibody or a functional fragment thereof, which provides an important source of raw materials for the detection of influenza A virus and has good activity or affinity.

[0007] In order to achieve the above-mentioned object, according to one aspect of the present invention, an antibody or a functional fragment thereof is provided, wherein the antibody or the functional fragment thereof comprises three complementarity determining regions of a heavy chain variable region having the amino acid sequence of any one of SEQ ID NOs: 17, 18, and 19 and three complementarity determining regions of a light chain variable region having the amino acid sequence of SEQ ID NO: 20.

[0008] To achieve the above objectives, according to two aspects of the present invention, an antibody or a functional fragment thereof is provided, wherein the antibody or the functional fragment thereof comprises the following complementarity determining regions:

[0009] HCDR1 comprising or consisting of the amino acid sequence shown in SEQ ID NO: 1;

[0010] HCDR2 comprising or consisting of the amino acid sequence shown in SEQ ID NO: 2;

[0011] HCDR3 comprising or consisting of the amino acid sequence shown in SEQ ID NO: 3;

[0012] LCDR1, which comprises or consists of the amino acid sequence shown in SEQ ID NO:4;

[0013] LCDR2, which comprises or consists of the amino acid sequence shown in SEQ ID NO: 5;

[0014] LCDR3 comprises or consists of the amino acid sequence shown in SEQ ID NO: 6.

[0015] To achieve the above-mentioned object, according to the third aspect of the present invention, an antibody or a functional fragment thereof is provided, comprising a heavy chain variable region and / or a light chain variable region, wherein the amino acid sequence of the heavy chain variable region is shown in any one of SEQ ID NOs: 17, 18, and 19; and the amino acid sequence of the light chain variable region is shown in SEQ ID NO: 20.

[0016] In order to achieve the above-mentioned object, according to the fourth aspect of the present invention, an antibody or a functional fragment thereof is provided, comprising a heavy chain and / or a light chain, wherein the amino acid sequence of the heavy chain is shown in any one of SEQ ID NO: 21, 22, and 23; and the amino acid sequence of the light chain is shown in SEQ ID NO: 24.

[0017] In order to achieve the above object, according to the fifth aspect of the present invention, an antibody conjugate is provided, wherein the antibody conjugate comprises the above antibody or a functional fragment thereof.

[0018] In order to achieve the above object, according to the sixth aspect of the present invention, a reagent or kit is provided, wherein the reagent or kit comprises the above-mentioned antibody or its functional fragment or the above-mentioned antibody conjugate.

[0019] To achieve the above-mentioned object, according to a seventh aspect of the present invention, a method for detecting influenza A virus is provided, comprising: a) contacting the above-mentioned antibody or functional fragment thereof, antibody conjugate, or reagent or kit with influenza A virus in a sample to be detected under conditions sufficient for an antibody / antigen binding reaction to occur, to form an immune complex; and b) detecting the presence of the immune complex, wherein the presence of the complex indicates the presence of the influenza A virus in the test sample.

[0020] In order to achieve the above object, according to the eighth aspect of the present invention, a nucleic acid is provided, which encodes the above antibody or a functional fragment thereof.

[0021] In order to achieve the above object, according to the ninth aspect of the present invention, a vector is provided, wherein the vector comprises the above nucleic acid.

[0022] In order to achieve the above object, according to the tenth aspect of the present invention, a cell is provided, wherein the cell comprises the above nucleic acid or vector.

[0023] In order to achieve the above object, according to the eleventh aspect of the present invention, a method for preparing the above antibody or a functional fragment thereof is provided, which comprises culturing the above cell.

[0024] To achieve the above-mentioned object, according to the twelfth aspect of the present invention, there is provided a use of the above-mentioned antibody or functional fragment thereof, antibody conjugate, reagent or kit in detecting or preparing a product for detecting influenza A virus. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0026] Figure 1 The results of reducing SDS-PAGE of Anti-FLUA 10D9 Rmb1 to Rmb3 are shown. DETAILED DESCRIPTION

[0027] In a first aspect, an embodiment of the present invention provides an antibody or a functional fragment thereof, wherein the antibody or the functional fragment thereof comprises three complementarity determining regions of a heavy chain variable region having the amino acid sequence of any one of SEQ ID NOs: 17, 18, and 19 and three complementarity determining regions of a light chain variable region having the amino acid sequence of SEQ ID NO: 20.

[0028] In the present invention, the term "antibody" is used in the broadest sense and may include full-length monoclonal antibodies, bispecific or multispecific antibodies, and chimeric antibodies, so long as they exhibit the desired biological activity.

[0029] As used herein, the terms "complementarity determining region," "CDR," or "CDRs" refer to the hypervariable regions of the heavy and light chains of immunoglobulins, and include one or more, or even all, of the amino acid residues that contribute substantially to the binding of an antibody or antigen-binding fragment to its recognized antigen or epitope. In specific embodiments of the present invention, CDRs refer to the hypervariable regions of the heavy and light chains of the antibody.

[0030] In the present invention, the heavy chain complementarity determining region is represented by HCDR, which includes HCDR1, HCDR2 and HCDR3; the light chain complementarity determining region is represented by LCDR, which includes LCDR1, LCDR2 and LCDR3.

[0031] Methods for defining CDRs are well known in the art and include the Kabat definition, the Chothia definition, the IMGT definition, the Contact definition, and the AbM definition. As used herein, the "Kabat definition" refers to the definition system described in Kabat et al., U. S. Pat. of Health and Human Services, "Sequence of Proteins of Immunological Interest" (1983).

[0032] "Chothia definition" refers to Chothia et al., J Mol Biol 196:901-917 (1987). There are other CDR definition methods that may not strictly follow one of the above schemes, but will still overlap with at least a portion of the CDR regions defined by Kabat, although they may be shortened or lengthened based on predictions or experimental results of specific residues or groups of residues. Exemplary defined CDRs are listed in Table 1 below, and the definitions in different literature vary slightly. Given the variable region amino acid sequence of an antibody, a person skilled in the art can routinely determine which residues comprise a specific CDR. It should be noted that CDRs defined by other methods other than those in Table 1 also fall within the scope of protection of the present disclosure.

[0033] Table 1: CDR Definition 1

[0034]

[0035]

[0036] 1 The numbering of all CDR definitions in Table 1 is based on the Kabat numbering system (see below), with amino acid numbers on the heavy chain represented by "H+number" and amino acid numbers on the light chain represented by "L+number." One of ordinary skill in the art can unambiguously assign this Kabat numbering system to any variable region sequence without relying on any experimental data other than the sequence itself. As used herein, "Kabat numbering" refers to the numbering system described in Kabat et al., U.S. Pat. of Health and Human Services, "Sequence of Proteins of Immunological Interest" (1983).

[0037] 2 "AbM" as used in Table 1 with a lowercase "b" refers to CDRs defined by Oxford Molecular's "AbM" antibody modeling software.

[0038] 3 If both H35A and H35B are absent, CDR-H1 ends at position 35; if only H35A is present, CDR-H1 ends at position 35A; if both H35A and H35B are present, CDR-H1 ends at position 35B.

[0039] 4 If both H35A and H35B are absent, CDR-H1 ends at position 32; if only H35A is present, CDR-H1 ends at position 33; if both H35A and H35B are present, CDR-H1 ends at position 34.

[0040] 5 If both H35A and H35B are absent, CDR-H1 ends at position 33; if only H35A is present, CDR-H1 ends at position 34; if both H35A and H35B are present, CDR-H1 ends at position 35.

[0041] According to an embodiment of the present invention, the complementarity determining regions are defined by any one system, or a combination of multiple systems, of Kabat, Chothia, IMGT, AbM or Contact.

[0042] In some optional embodiments of the present invention, in the complementarity determining regions, HCDR1, HCDR2, HCDR3, LCDR1, LCDR2 and LCDR3 are defined by the Kabat system.

[0043] In some optional embodiments of the present invention, in the complementarity determining regions, HCDR1, HCDR2, HCDR3, LCDR1, LCDR2 and LCDR3 are defined by the Chothia system.

[0044] In some optional embodiments of the present invention, among the complementarity determining regions, HCDR1, HCDR2, HCDR3, LCDR1, LCDR2 and LCDR3 are defined by the IMGT system.

[0045] In some optional embodiments of the present invention, among the complementarity determining regions, HCDR1, HCDR2, HCDR3, LCDR1, LCDR2 and LCDR3 are defined by the AbM system.

[0046] In some optional embodiments of the present invention, in the complementarity determining regions, HCDR1, HCDR2, HCDR3, LCDR1, LCDR2 and LCDR3 are defined by the Contact system.

[0047] In some optional embodiments of the present invention, in the complementary determining regions, HCDR1, HCDR2, HCDR3, LCDR1, LCDR2 and LCDR3 are defined by a combination of Kabat, Chothia, IMGT, AbM or Contact systems.

[0048] According to an embodiment of the present invention, the Kabat numbering positions corresponding to the amino acid sequences of the complementarity determining regions defined by the Kabat, Chothia, AbM or IMGT systems are as follows:

[0049] CDR Kabat AbM IMGT Chothia HCDR1 H31~H35A H26~H35A H26~H34 H26~H33 HCDR2 H50~H65 H50~H58 H51~H57 H52~H56 HCDR3 H95~H102 H95~H102 H93~H102 H95~H102 LCDR1 L24~L34 L24~L34 L27~L32 L24~L34 LCDR2 L50~L56 L50~L56 L50~L51 L50~L56 LCDR3 L89~L97 L89~L97 L89~L97 L89~L97

[0050] In an optional embodiment, an embodiment of the present invention provides an antibody or a functional fragment thereof, wherein the antibody or the functional fragment thereof comprises the following complementarity determining regions:

[0051] HCDR1 comprises or consists of the amino acid sequence shown in SEQ ID NO: 1.

[0052] HCDR2 comprises or consists of the amino acid sequence shown in SEQ ID NO: 2.

[0053] HCDR3 comprises or consists of the amino acid sequence shown in SEQ ID NO: 3.

[0054] LCDR1 comprises or consists of the amino acid sequence shown in SEQ ID NO: 4.

[0055] LCDR2 comprises or consists of the amino acid sequence shown in SEQ ID NO: 5.

[0056] LCDR3 comprises or consists of the amino acid sequence shown in SEQ ID NO: 6.

[0057] In the present invention, the "framework region" or "FR" region includes the heavy chain framework region and the light chain framework region, and refers to the region of the antibody heavy chain variable region and the light chain variable region excluding CDR; wherein the heavy chain framework region can be further subdivided into adjacent regions separated by CDR, including HFR1, HFR2, HFR3 and HFR4 framework regions; the light chain framework region can be further subdivided into adjacent regions separated by CDR, including LFR1, LFR2, LFR3 and LFR4 framework regions.

[0058] In the present invention, the heavy chain variable region is obtained by arranging and connecting the following numbered CDRs and FRs in the following combinations: HFR1-HCDR1-HFR2-HCDR2-HFR3-HCDR3-HFR4; the light chain variable region is obtained by arranging and connecting the following numbered CDRs and FRs in the following combinations: LFR1-LCDR1-LFR2-LCDR2-LFR3-LCDR3-LFR4.

[0059] In an optional embodiment, the antibody or functional fragment thereof further has at least one of HFR1, HFR2, HFR3, HFR4, LFR1, LFR2, LFR3 and LFR4;

[0060] The HFR1 comprises / is as SEQ ID NO: 7 or an amino acid sequence having at least 80% identity thereto;

[0061] The HFR2 comprises / is as SEQ ID NO: 8 or an amino acid sequence having at least 80% identity thereto;

[0062] The HFR3 comprises / is SEQ ID NO: 9 or an amino acid sequence having at least 80% identity thereto;

[0063] The HFR4 comprises / is as SEQ ID NO: 10 or an amino acid sequence having at least 80% identity thereto;

[0064] The LFR1 comprises / is SEQ ID NO: 11 or an amino acid sequence having at least 80% identity thereto;

[0065] The LFR2 comprises / is SEQ ID NO: 12 or an amino acid sequence having at least 80% identity thereto;

[0066] The LFR3 comprises / is SEQ ID NO: 13 or an amino acid sequence having at least 80% identity thereto;

[0067] The LFR4 comprises / is SEQ ID NO: 14 or an amino acid sequence having at least 80% identity thereto;

[0068] It should be noted that, in other embodiments, the amino acid sequences of the framework regions of the antibodies or functional fragments thereof provided by the present invention may be at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to the corresponding framework regions (SEQ ID NO: 7, 8, 9, 10, 11, 12, 13 or 14).

[0069] In an optional embodiment, the HFR1 comprises / is represented by the amino acid sequence shown in SEQ ID NO:25.

[0070] In an alternative embodiment, the HFR3 comprises / is represented by the amino acid sequence shown in SEQ ID NO:26.

[0071] In an optional embodiment, the antibody or its functional fragment has a KD of less than 4.91×10 -10 The affinity of M for binding to influenza A virus.

[0072] In an optional embodiment, the antibody or its functional fragment has a KD≤10 -10 M, KD≤10 -11 M or KD≤10 -12 The affinity of M for binding to influenza A virus.

[0073] In an optional embodiment, the antibody or its functional fragment has a KD ≤ 2.49×10 -12 The affinity of M binds to influenza A virus.

[0074] There are many methods for determining antibody affinity (KD). Based on the detection principle, they can be divided into thermodynamic detection methods, kinetic detection methods, and dynamic equilibrium detection methods. Among them, thermodynamic detection methods such as isothermal titration calorimetry (ITC) are common; kinetic detection methods such as surface plasmon resonance (SPR) and biofilm interferometry (BLI) are common; and dynamic equilibrium detection methods such as enzyme-linked immunosorbent assay (ELISA) are common.

[0075] In alternative embodiments, KD is determined using a kinetic assay; optionally, surface plasmon resonance, for example, by using a kinetic assay such as System of biosensor systems.

[0076] In a second aspect, an embodiment of the present invention provides an antibody or a functional fragment thereof, comprising a heavy chain variable region and / or a light chain variable region, wherein the amino acid sequence of the heavy chain variable region is shown in any one of SEQ ID NO: 17, 18, and 19, and the amino acid sequence of the light chain variable region is shown in SEQ ID NO: 20.

[0077] In an optional embodiment, the heavy chain variable region and light chain variable region defined in the antibody or functional fragment thereof described in the first or second aspect are selected from any one of the following combinations:

[0078] combination Heavy chain variable region Light chain variable region 1 SEQ ID NO: 17 SEQ ID NO:20 2 SEQ ID NO: 18 SEQ ID NO:20 3 SEQ ID NO: 19 SEQ ID NO:20

[0079] In an optional embodiment, the antibody or functional fragment thereof described in the first or second aspect further comprises a constant region.

[0080] In alternative embodiments, the constant region comprises a heavy chain constant region and / or a light chain constant region.

[0081] In an optional embodiment, the heavy chain constant region is selected from the heavy chain constant region of IgG1, IgG2, IgG3, IgG4, IgA, IgM, IgE or IgD, and the light chain constant region is selected from the κ type or λ type light chain constant region.

[0082] In an alternative embodiment, the species origin of the constant region is cow, horse, dairy cow, pig, sheep, rat, mouse, dog, cat, rabbit, donkey, deer, mink, chicken, duck, goose, turkey, fighting cock or human.

[0083] In an alternative embodiment, the species origin of the constant region is mouse.

[0084] In an optional embodiment, the heavy chain constant region sequence (CH) is shown as SEQ ID NO:15, and the light chain constant region (CL) sequence is shown as SEQ ID NO:16.

[0085] It should be noted that, in other embodiments, the constant region sequence may be at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to the above-mentioned constant region (SEQ ID NO: 15 or 16).

[0086] In an optional embodiment, the functional fragment is selected from any one of F(ab')2, Fab', Fab, Fv and scFv of the antibody.

[0087] The functional fragments of the above-mentioned antibodies generally have the same binding specificity as the antibody from which they are derived. Based on the disclosure herein, those skilled in the art will readily appreciate that the functional fragments of the above-mentioned antibodies can be obtained by, for example, enzymatic digestion (including pepsin or papain) and / or by chemical reduction cleavage of disulfide bonds. Based on the structure of the intact antibody disclosed herein, those skilled in the art can readily obtain the above-mentioned functional fragments.

[0088] Functional fragments of the above antibodies can also be synthesized by recombinant genetic techniques known to those skilled in the art or by, for example, an automatic peptide synthesizer, such as those sold by Applied BioSystems.

[0089] In a third aspect, the present invention provides an antibody or a functional fragment thereof, comprising a heavy chain and / or a light chain, wherein the amino acid sequence of the heavy chain is shown in any one of SEQ ID NO: 21, 22, and 23, and the amino acid sequence of the light chain is shown in SEQ ID NO: 24.

[0090] In an optional embodiment, the antibody or functional fragment thereof described in the first, second, or third aspect above comprises any combination of the following heavy chains and light chains:

[0091] combination Heavy chain light chain 1 SEQ ID NO:21 SEQ ID NO:24 2 SEQ ID NO:22 SEQ ID NO:24 3 SEQ ID NO:23 SEQ ID NO:24

[0092] In a fourth aspect, the present invention provides an antibody conjugate comprising the above-mentioned antibody or a functional fragment thereof.

[0093] In an optional embodiment, the above-mentioned antibody conjugate further comprises biotin or a biotin derivative coupled to the antibody or a functional fragment thereof.

[0094] In an optional embodiment, the antibody conjugate further comprises a label coupled to the antibody or a functional fragment thereof.

[0095] In an optional embodiment, the above-mentioned marker refers to a class of substances with properties that can be directly observed by the naked eye or detected or detected by an instrument, such as luminescence, color development, radioactivity, etc., through which qualitative or quantitative detection of the corresponding target can be achieved.

[0096] In an alternative embodiment, the label includes but is not limited to fluorescent dyes, enzymes, radioisotopes, chemiluminescent reagents and nanoparticle labels.

[0097] In actual use, those skilled in the art can select a suitable marker according to the detection conditions or actual needs. No matter which marker is used, it falls within the scope of protection of the present invention.

[0098] In an optional embodiment, the fluorescent dyes include but are not limited to fluorescein dyes and their derivatives (for example, including but not limited to fluorescein isothiocyanate (FITC), hydroxyfluorescein (FAM), tetrachlorofluorescein (TET), etc. or their analogs), rhodamine dyes and their derivatives (for example, including but not limited to red rhodamine (RBITC), tetramethylrhodamine (TAMRA), rhodamine B (TRITC), etc. or their analogs), Cy series dyes and their derivatives (for example, including but not limited to Cy2, Cy3, Cy3B, Cy3.5, C y5, Cy5.5, Cy3, etc. or their analogs), Alexa series dyes and their derivatives (for example, including but not limited to AlexaFluor350, 405, 430, 488, 532, 546, 555, 568, 594, 610, 33, 647, 680, 700, 750, etc. or their analogs) and protein dyes and their derivatives (for example, including but not limited to phycoerythrin (PE), phycocyanin (PC), allophycocyanin (APC), peridinin-chlorophyll protein (preCP), etc.).

[0099] In alternative embodiments, the enzyme includes, but is not limited to, horseradish peroxidase, alkaline phosphatase, β-galactosidase, glucose oxidase, carbonic anhydrase, acetylcholinesterase, and glucose-6-phosphate deoxidase.

[0100] In an optional embodiment, the radioactive isotopes include but are not limited to 212Bi, 131I, 111In, 90Y, 186Re, 211At, 125I, 188Re, 153Sm, 213Bi, 32P, 94mTc, 99mTc, 203Pb, 67Ga, 68Ga, 43Sc, 47Sc, 110mIn, 97Ru, 62Cu, 64Cu, 67Cu, 68Cu, 86Y, 88Y, 121Sn, 161Tb, 166Ho, 105Rh, 177Lu, 172Lu and 18F.

[0101] In an optional embodiment, the chemiluminescent reagent includes but is not limited to luminol and its derivatives, lucigenin, crustacean fluorescein and its derivatives, ruthenium bipyridine and its derivatives, acridinium esters and their derivatives, dioxetanes and their derivatives, lophanes and their derivatives, and peroxalates and their derivatives.

[0102] In an optional embodiment, the nanoparticle markers include but are not limited to nanoparticles, colloids, organic nanoparticles, magnetic nanoparticles, quantum dot nanoparticles and rare earth complex nanoparticles.

[0103] In alternative embodiments, the colloid includes, but is not limited to, colloidal metals, disperse dyes, dye-labeled microspheres, and latex.

[0104] In an alternative embodiment, the colloidal metal includes, but is not limited to, colloidal gold, colloidal silver, and colloidal selenium.

[0105] In an optional embodiment, the colloidal metal is colloidal gold.

[0106] In an optional embodiment, the above-mentioned antibody conjugate further comprises a solid phase carrier coupled to the antibody or its functional fragment.

[0107] In an alternative embodiment, the solid support is selected from microspheres, plates, and membranes.

[0108] In an optional embodiment, the solid phase carrier includes but is not limited to magnetic microspheres, plastic microspheres, plastic particles, microplates, glass, capillaries, nylon and nitrocellulose membranes.

[0109] In a fifth aspect, the present invention provides a reagent or a kit, which comprises the above-mentioned antibody or a functional fragment thereof or the above-mentioned antibody conjugate.

[0110] As previously mentioned, the antibodies or functional fragments thereof in some embodiments or examples of the present invention can effectively bind to influenza A virus. Therefore, the reagents or kits containing the influenza A virus antibodies or functional fragments thereof can effectively detect influenza A virus qualitatively or quantitatively. The reagents or kits provided by the present invention can be used, for example, in immunoblotting, immunoprecipitation, and other assays that utilize the specific binding properties of influenza A virus and its antibodies. As previously mentioned, the antibodies or functional fragments thereof in some embodiments or examples of the present invention have higher binding activity or affinity for influenza A virus. Therefore, the reagents or kits containing the antibodies or functional fragments thereof have higher detection sensitivity or specificity.

[0111] In a sixth aspect, the present invention provides a method for detecting influenza A virus, comprising: a) contacting the above-mentioned antibody or functional fragment thereof, antibody conjugate, reagent or kit with influenza A virus in a sample to be detected under conditions sufficient for an antibody / antigen binding reaction to occur, to form an immune complex; and b) detecting the presence of the immune complex, wherein the presence of the complex indicates the presence of the influenza A virus in the test sample;

[0112] In an optional embodiment, the immune complex further comprises a second antibody, which binds to the antibody or a functional fragment thereof.

[0113] In an alternative embodiment, the immune complex further comprises a second antibody, which binds to influenza A virus.

[0114] In a seventh aspect, the present invention provides a nucleic acid molecule encoding the above-mentioned antibody or a functional fragment thereof.

[0115] In an eighth aspect, the present invention provides a vector comprising the above-mentioned nucleic acid molecule.

[0116] In a ninth aspect, the present invention provides cells containing the above-mentioned nucleic acid molecule or vector.

[0117] In a tenth aspect, the present invention provides a method for preparing an antibody or a functional fragment thereof, comprising: culturing the cell as described above.

[0118] In an eleventh aspect, the present invention provides uses of the above-mentioned antibodies or functional fragments thereof, antibody conjugates, or the above-mentioned reagents or kits in detecting influenza A virus, diagnosing influenza A virus infection, or preparing products for detecting influenza A virus.

[0119] In a twelfth aspect, the present invention provides a method for diagnosing influenza A virus infection in a subject, comprising: a) contacting the above-mentioned antibody or its functional fragment, antibody conjugate, reagent or kit with a sample from the subject under conditions sufficient for an antibody / antigen binding reaction to form an immune complex; and b) detecting the immune complex.

[0120] Based on the amino acid sequence of the antibody or its functional fragment disclosed in the present invention, those skilled in the art can easily conceive of using genetic engineering technology or other technologies (chemical synthesis, recombinant expression) to prepare the antibody or its functional fragment. For example, the antibody or its functional fragment can be isolated and purified from the culture product of a recombinant cell that can recombinantly express the antibody or its functional fragment as described in any of the above items. This is easy to achieve for those skilled in the art. Based on this, no matter what technology is used to prepare the antibody or its functional fragment of the present invention, it falls within the scope of protection of the present invention.

[0121] To make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer are used. Where the manufacturer of the reagents or instruments is not specified, all are conventional products that can be purchased commercially.

[0122] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art to which this disclosure belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the preparations or unit doses herein, some methods and materials are now described. Unless otherwise indicated, the techniques employed or contemplated herein are standard methods. Materials, methods, and examples are illustrative and non-limiting only.

[0123] The practice of the present invention will employ, unless otherwise indicated, conventional techniques of cell biology, molecular biology (including recombinant techniques), microbiology, biochemistry, and immunology, which are within the capabilities of a person skilled in the art. The technique is fully explained in the literature, for example, in Molecular Cloning: A Laboratory Manual, 2nd ed. (Sambrook et al., 1989); Oligonucleotide Synthesis (MJ Gait, ed., 1984); Animal Cell Culture (RI Freshney, ed., 1987); Methods in Enzymology (Academic Press, Inc.); Handbook of Experimental Immunology (DM Weir and CC Blackwell, eds.); Gene Transfer Vectors for Mammalian Cells (JM Miller and MP Calos, eds., 1987); Current Protocols in Molecular Biology (FM Ausubel et al., eds., 1987); and PCR: The Polymerase Chain Reaction. Reaction" (Mullis et al., eds., 1994); and Current Protocols in Immunology (JE Coligan et al., eds., 1991), each of which is expressly incorporated herein by reference.

[0124] The features and performance of the present invention are further described in detail below with reference to the embodiments.

[0125] Example 1 Preparation of Anti-FLUA 10D9 Monoclonal Antibody

[0126] In this example, restriction endonucleases and Prime Star DNA polymerase were purchased from Takara. MagExtractor-RNA extraction kit was purchased from TOYOBO. BD SMART TMThe RACE cDNA Amplification Kit was purchased from Takara. The pMD-18T vector was also purchased from Takara. The plasmid extraction kit was purchased from Tiangen. Primer synthesis and gene sequencing were performed by Invitrogen. The hybridoma cell line secreting the anti-FLUA 10D9 monoclonal antibody was a pre-existing hybridoma cell line generated in our laboratory and revived for future use.

[0127] (1) Antibody gene preparation

[0128] mRNA was extracted from a hybridoma cell line secreting the Anti-FLUA 10D9 monoclonal antibody. DNA products were obtained by RT-PCR. This product was PCR-amplified with rTaq DNA polymerase and inserted into the pMD-18T vector. The resulting cells were transformed into DH5α competent cells. After colonies grew, the Heavy Chain and Light Chain gene clones were obtained, and four clones each were sent to a gene sequencing company for sequencing.

[0129] (2) Sequence analysis of the variable region gene of Anti-FLUA 10D9 antibody

[0130] The gene sequences obtained by the above sequencing were placed in the Kabat antibody database for analysis, and VNTI11.5 software was used for analysis to determine that the genes amplified by the heavy chain and light chain primer pairs were correct. Among them, in the gene fragment amplified by the Light Chain, the VL gene sequence was 321 bp, preceded by a 57 bp leader peptide sequence; in the gene fragment amplified by the Heavy Chain primer pair, the VH gene sequence was 348 bp, belonging to the VH1 gene family, and preceded by a 57 bp leader peptide sequence.

[0131] (3) Construction of recombinant antibody expression plasmid

[0132] pcDNA TM 3.4 The vector is a recombinant antibody eukaryotic expression vector constructed by using the pMD-18T vector. Multiple cloning restriction sites such as HindIII, BamHI, and EcoRI have been introduced into the vector, and the vector is named pcDNA3.4A expression vector, hereinafter referred to as 3.4A expression vector. Based on the sequencing results of the antibody variable region genes in the pMD-18T vector, specific primers for the VL and VH genes of the antibody were designed, with HindIII and EcoRI restriction sites and protective bases at both ends, respectively. PCR amplification was used to amplify a 0.72kb Light Chain gene fragment and a 1.42kb Heavy Chain gene fragment.

[0133] The Heavy Chain and Light Chain gene fragments were digested with HindIII / EcoRI, and the 3.4A vector was digested with HindIII / EcoRI. After the fragments and vectors were purified and recovered, the Heavy Chain gene and Light Chain gene were respectively connected to the 3.4A expression vector to obtain the recombinant expression plasmids of Heavy Chain and Light Chain, respectively.

[0134] 2. Recombinant Antibody Production

[0135] Resuscitate HEK293 cells in advance and subculture them into 200 ml system to make the cell density reach 3-5×10 6 cells / ml cell density reaches the selected antibody concentration and cells, cell viability>95%; centrifuge and wash the cells, re-dissolve with culture medium, and adjust the cell density to 2.9×10 6 Cells were washed with 100 μg of culture medium and re-dissolved. This was also used as a cell diluent. Plasmid DNA and transfection reagent diluents were prepared separately using culture medium. The transfection reagent diluent was added to the plasmid DNA diluent, mixed, and allowed to stand at room temperature for 15 minutes. The mixture was slowly added to the cell diluent over 1 minute, mixed, and sampled. The viability of the cells after transfection was recorded and observed. The cells were cultured in a 35°C constant temperature incubator at 120 rpm and 8% CO2. After 13 days, the samples were collected by centrifugation. The supernatant was affinity purified using a protein A affinity chromatography column. 6 μg of the purified antibody was subjected to reducing SDS-PAGE. The electrophoresis pattern is shown in the figure. Two bands were shown after reducing SDS-PAGE, one with an Mr of 50 KD (heavy chain) and the other with an Mr of 28 KD (light chain).

[0136] The obtained antibody was named Anti-FLUA 10D9Rmb1. Anti-FLUA10D9Rmb1 was mutated to obtain a mutant antibody. The sequences of the heavy chain (H) and light chain (L) of the above antibody are shown in the following table:

[0137] Table 2 Antibody sequences

[0138] Antibody name Heavy chain light chain Anti-FLUA 10D9 Rmb1 SEQ ID NO:21 SEQ ID NO:24 Anti-FLUA 10D9Rmb2 SEQ ID NO:22 SEQ ID NO:24 Anti-FLUA 10D9Rmb3 SEQ ID NO:23 SEQ ID NO:24

[0139] Example 2 Performance testing of antibodies

[0140] 1. Affinity Analysis

[0141] Purified antibodies were diluted in advance, and recombinant influenza A antigen (obtained from Feipeng Bio) was serially diluted. Binding and dissociation curves were measured on a Biacore 8K+ instrument using a CM5 chip pre-coupled with goat anti-mouse IgG. The instrument automatically fitted the affinity constant, association rate, and dissociation rate. (KD represents the equilibrium dissociation constant, also known as the affinity constant; ka represents the association rate; and kd represents the dissociation rate.)

[0142] Table 3 Affinity data

[0143] Sample name KD ka kd comparison 4.91E-10 1.27E+06 6.23E-04 Anti-FLUA 10D9 Rmb1 2.43E-12 3.15E+07 7.66E-05 Anti-FLUA 10D9Rmb2 2.38E-12 3.05E+07 7.26E-05 Anti-FLUA 10D9Rmb3 2.49E-12 3.27E+07 8.14E-05

[0144] 2. Activity Identification

[0145] Dilute influenza A recombinant antigen (obtained from Feipeng Bio) to 3 μg / ml in coating buffer (mainly NaHCO₃), add 100 μL per well, and incubate at 4°C overnight. The next day, wash twice with wash buffer (mainly Na₂HPO₄ + NaCl) and pat dry. Add blocking buffer (20% BSA + 80% PBS) at 120 μL per well and incubate at 37°C for 1 hour, then pat dry. Add diluted purified antibody and control antibody at 100 μL / well and incubate at 37°C for 30 minutes. Wash five times with wash buffer and pat dry. Add goat anti-mouse IgG-HRP at 100 μL per well and incubate at 37°C for 30 minutes. Wash five times with wash buffer and pat dry. Add chromogen solution A (50 μL / well) and chromogen solution B (50 μL / well) for 10 minutes. Add stop solution (50 μL / well). Read the OD value at 450 nm (reference 630 nm) on a microplate reader.

[0146] Note: Solution A (main ingredients: citric acid + sodium acetate + acetanilide + urea peroxide); Solution B (main ingredients: citric acid

[0147] + EDTA·2Na+TMB+concentrated HCL); stop solution (EDTA·2Na+concentrated H2SO4)

[0148] Table 4 Activity data

[0149] Concentration (ng / ml) 19.531 9.766 4.883 2.441 1.221 0.000 comparison 0.998 0.602 0.391 0.267 0.167 0.029 Anti-FLUA 10D9 Rmb1 1.503 0.841 0.508 0.334 0.126 0.056 Anti-FLUA 10D9Rmb2 1.513 0.839 0.498 0.350 0.201 0.045 Anti-FLUA 10D9Rmb3 1.506 0.844 0.503 0.322 0.132 0.042

[0150] 3. Stability assessment

[0151] The above-mentioned antibody was placed at 4°C (refrigerator), -80°C (freezer), and 37°C (incubator) for 21 days. Samples were collected at 7, 14, and 21 days for status observation, and the 21-day sample was tested for activity. The results showed that no significant changes in protein status were observed under the three test conditions for 21 days, and the activity did not show a downward trend with increasing test temperature, indicating that the above-mentioned antibody is stable. Table 5 below shows the OD results of the enzyme immunoassay activity assay of the antibody Anti-FLUA10D9Rmb1 after 21 days of testing.

[0152] Table 5 Stability data

[0153] Sample concentration (ng / ml) 19.531 9.766 0.000 4℃, 21-day samples 1.487 0.837 0.014 -80℃, 21-day sample 1.495 0.842 0.002 37℃, 21-day samples 1.506 0.843 0.016

[0154] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

[0155] Some of the amino acid sequences involved in this application are as follows:

[0156] Table 6 Amino acid sequence table

[0157]

[0158]

Claims

1. An anti-influenza A virus antibody or a functional fragment thereof, characterized in that: The antibody or its functional fragment has three complementarity determining regions of the heavy chain variable region of any one of the amino acid sequences SEQ ID NO: 17, 18, and 19 and three complementarity determining regions of the light chain variable region having the amino acid sequence SEQ ID NO: 20, and the complementarity determining regions are defined by any one of the systems of Kabat, Chothia, IMGT, AbM or Contact.

2. An anti-influenza A virus antibody or a functional fragment thereof, characterized in that: The antibody or its functional fragment comprises the following complementarity determining regions: The amino acid sequence of HCDR1 is shown in SEQ ID NO: 1; The amino acid sequence of HCDR2 is shown in SEQ ID NO: 2; The amino acid sequence of HCDR3 is shown in SEQ ID NO: 3; The amino acid sequence of LCDR1 is shown in SEQ ID NO:4; The amino acid sequence of LCDR2 is shown in SEQ ID NO:5; The amino acid sequence of LCDR3 is shown in SEQ ID NO:6; The complementarity determining regions are numbered using the Kabat system.

3. The antibody or functional fragment thereof according to claim 1 or 2, characterized in that The antibody or functional fragment thereof further comprises HFR1, HFR2, HFR3, HFR4, LFR1, LFR2, LFR3 and LFR4.

4. The antibody or functional fragment thereof according to claim 3, characterized in that The HFR1 comprises SEQ ID NO: 7 or an amino acid sequence having at least 80% identity thereto; The HFR2 comprises SEQ ID NO: 8 or an amino acid sequence having at least 80% identity thereto; The HFR3 comprises SEQ ID NO: 9 or an amino acid sequence having at least 80% identity thereto; The HFR4 comprises SEQ ID NO: 10 or an amino acid sequence having at least 80% identity thereto; The LFR1 comprises SEQ ID NO: 11 or an amino acid sequence having at least 80% identity thereto; The LFR2 comprises SEQ ID NO: 12 or an amino acid sequence having at least 80% identity thereto; The LFR3 comprises SEQ ID NO: 13 or an amino acid sequence having at least 80% identity thereto; The LFR4 comprises SEQ ID NO: 14 or an amino acid sequence having at least 80% identity thereto.

5. The antibody or functional fragment thereof according to claim 1 or 2, characterized in that The antibody or its functional fragment has a KD of less than 4.91×10 -10 The affinity of M binds to influenza A virus.

6. An anti-influenza A virus antibody or a functional fragment thereof, comprising a heavy chain variable region and a light chain variable region, characterized in that: The amino acid sequence of the heavy chain variable region is shown in any one of SEQ ID NOs: 17, 18, and 19; the amino acid sequence of the light chain variable region is shown in SEQ ID NO:

20.

7. The antibody or functional fragment thereof according to any one of claims 1 to 4 and 6, characterized in that: The antibody or functional fragment thereof further comprises a constant region.

8. The antibody or functional fragment thereof according to claim 7, characterized in that The constant region includes a heavy chain constant region and a light chain constant region.

9. The antibody or functional fragment thereof according to claim 8, characterized in that The heavy chain constant region is selected from the heavy chain constant region of IgG1, IgG2, IgG3, IgG4, IgA, IgM, IgE or IgD; the light chain constant region is selected from the κ type or λ type light chain constant region.

10. The antibody or functional fragment thereof according to claim 7, characterized in that: The species origin of the constant region is cow, horse, pig, sheep, goat, rat, mouse, dog, cat, rabbit, donkey, deer, mink, chicken, duck, goose or human.

11. The antibody or functional fragment thereof according to claim 7, characterized in that: The species origin of the constant region is mouse.

12. The antibody or functional fragment thereof according to claim 8, characterized in that The heavy chain constant region sequence is as shown in SEQ ID NO: 15 or has at least 80% identity thereto, and the light chain constant region sequence is as shown in SEQ ID NO: 16 or has at least 80% identity thereto.

13. The antibody or functional fragment thereof according to any one of claims 1 to 2, 4, and 6, wherein: The functional fragment is selected from any one of F(ab')2, Fab', Fab, Fv and scFv of the antibody.

14. An anti-influenza A virus antibody comprising a heavy chain and a light chain, characterized in that: The amino acid sequence of the heavy chain is shown in any one of SEQ ID NOs: 21, 22, and 23; the amino acid sequence of the light chain is shown in SEQ ID NO:

24.

15. An antibody conjugate, characterized in that The antibody conjugate comprises the antibody or functional fragment thereof according to any one of claims 1 to 13 or the antibody according to claim 14 and biotin or a label coupled to the antibody or functional fragment thereof.

16. The antibody conjugate according to claim 15, characterized in that The label is selected from fluorescent dyes, enzymes, radioisotopes, chemiluminescent reagents and nanoparticle labels.

17. An antibody conjugate, characterized in that The antibody conjugate comprises the antibody or functional fragment thereof according to any one of claims 1 to 13 or the antibody according to claim 14 and a solid phase carrier coupled to the antibody or functional fragment thereof.

18. The antibody conjugate according to claim 17, characterized in that The solid support is selected from microspheres, plates and membranes.

19. A reagent, characterized in that The reagent comprises the antibody or functional fragment thereof according to any one of claims 1 to 13, the antibody according to claim 14, or the antibody conjugate according to any one of claims 15 to 18.

20. A kit, characterized in that The kit comprises the antibody or functional fragment thereof according to any one of claims 1 to 13, the antibody according to claim 14, or the antibody conjugate according to any one of claims 15 to 18.

21. Use of the antibody or functional fragment thereof according to any one of claims 1 to 14, the antibody according to claim 14, or the antibody conjugate according to any one of claims 15 to 18 in the preparation of a product for detecting influenza A virus, characterized in that: include: a) contacting the antibody or functional fragment thereof according to any one of claims 1 to 13, the antibody according to claim 14, or the antibody conjugate according to any one of claims 15 to 18 with influenza A virus in a sample to be tested under conditions sufficient for an antibody / antigen binding reaction to form an immune complex; and b) detecting the presence of the immune complex, wherein the presence of the complex indicates the presence of the influenza A virus in the test sample.

22. The use according to claim 21, characterized in that The immune complex further comprises a second antibody that binds to the antibody or a functional fragment thereof.

23. The use according to claim 21, characterized in that The immune complex also includes a second antibody that binds to the influenza A virus.

24. A nucleic acid, characterized in that It encodes the antibody or functional fragment thereof according to any one of claims 1 to 13 or the antibody according to claim 14.

25. A carrier, characterized in that It contains the nucleic acid according to claim 24.

26. A cell, characterized in that It contains the nucleic acid according to claim 24 or the vector according to claim 25.

27. A method for preparing the antibody or functional fragment thereof according to any one of claims 1 to 13 or the antibody according to claim 14, comprising: Cultivate the cell of claim 26.

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