Non-specific reaction inhibitor, method for inhibiting non-specific reaction, reagent for biochemical measurement, reagent kit for biochemical measurement, and biochemical measurement method

Abstract

This non-specific reaction inhibitor used for biochemical measurement comprises as active ingredients: (a) an antibody or a fragment thereof; and (b) a copolymer containing (1) a first repeating unit having a linear or branched alkyl group having 12-40 carbon atoms and (2) a second repeating unit having a cationic moiety and an anionic moiety.

Description

Non-specific reaction inhibitor, non-specific reaction inhibition method, biochemical measurement reagent, biochemical measurement reagent kit, and biochemical measurement method

[0001] The present invention relates to a non-specific reaction inhibitor, a method for inhibiting a non-specific reaction, a reagent for biochemical measurement, a reagent kit for biochemical measurement, and a biochemical measurement method. This application claims priority to provisional application No. 63 / 572,367, filed in the United States on April 1, 2024, the contents of which are incorporated herein by reference.

[0002] Biochemical assays have been known as a means of detecting various components contained in human biological samples. Among these biochemical assays, immunoassays are highly specific because they utilize specific binding between proteins, such as antigen-antibody reactions.

[0003] However, because various substances other than the target substance are present in biological samples, binding not based on the original specific reaction may occur or the specific immune reaction may be hindered. These are called non-specific reactions, and the substances that cause them are sometimes called non-specific factors. When non-specific reactions occur in biochemical measurements, measurement errors occur. For this reason, various non-specific factors have been elucidated, and methods to suppress non-specific reactions have been investigated.

[0004] For example, Patent Document 1 discloses a method of adding an animal-derived antibody such as an anti-human IgG antibody, an anti-human IgA antibody, or an anti-human IgM antibody to a reagent as a method of suppressing non-specific reactions, and Patent Document 2 discloses a method of using a polycarboxylic acid surfactant.

[0005] JP 07-012818 A JP 2013-205408 A

[0006] The method of suppressing nonspecific reactions using animal-derived antibodies, etc., described in Patent Document 1, is still in practical use with various reagents. However, even these antibodies cannot suppress some nonspecific reactions. The method using surfactants described in Patent Document 2 has the problem of reduced measurement sensitivity depending on the concentration added. For this reason, the antibody-based nonspecific reaction suppression method described in Patent Document 1 remains the mainstream. However, the inventors' tests have revealed that conventional antibody-based nonspecific reaction suppression methods have a so-called "compatibility" with the measurement sample. In other words, a nonspecific reaction suppressor that is effective for a specific sample can increase nonspecific reactions for another sample, reducing measurement accuracy. This has been a major obstacle to developing more accurate biochemical measurement reagents. Therefore, there is a need for a nonspecific reaction suppressor that is broadly effective for a variety of samples.

[0007] One object of the present invention is to provide a non-specific reaction inhibitor, a method for inhibiting a non-specific reaction, a biochemical assay reagent, a biochemical assay reagent kit, and a biochemical assay method. As a result of extensive research, the inventors have discovered that by combining (a) a non-specific reaction inhibitor containing an antibody or a fragment thereof (hereinafter sometimes simply referred to as "antibody, etc.") as an active ingredient with (b) a non-specific reaction inhibitor containing a copolymer (hereinafter sometimes simply referred to as "copolymer") as an active ingredient, which includes (1) a first repeating unit having a linear or branched alkyl group having 12 to 40 carbon atoms and (2) a second repeating unit having both a cationic moiety and an anionic moiety, non-specific reactions can be inhibited without impairing the non-specific reaction inhibitory effects of both. Furthermore, the inventors have obtained the unexpected effect that, when used in combination with a sample in which non-specific reactions have been increased by the antibody, etc., the increase in non-specific reactions caused by the antibody, etc., is prevented. This is an achievement that will greatly contribute to the development of highly accurate biochemical assay reagents.

[0008] The present invention encompasses the following aspects: [1] A non-specific reaction inhibitor for use in biochemical measurements, comprising, as active ingredients, (a) an antibody or a fragment thereof, and (b) a copolymer comprising (1) a first repeating unit having a linear or branched alkyl group having 12 to 40 carbon atoms, and (2) a second repeating unit having a cationic moiety and an anionic moiety. [2] The non-specific reaction inhibitor according to [1], wherein the first repeating unit has a structure represented by formula (1). (In formula (1), R １ is a hydrogen atom or a methyl group, X is NH or an oxygen atom, and A is a linear or branched alkyl group having 12 to 40 carbon atoms.) [3] The non-specific reaction inhibitor according to [1] or [2], wherein the cationic moiety of the second repeating unit is a quaternary ammonium group. [4] The non-specific reaction inhibitor according to any one of [1] to [3], wherein the second repeating unit has a structure represented by formula (2) and / or formula (3). (In formula (2), R ２ is a hydrogen atom or a methyl group, and R ３ and R ４ are each independently a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and Y １ is an NH or oxygen atom, and Z is SO ３ － or COO － wherein n and m are each independently an integer of 1 to 5. (In formula (3), R ５ is a hydrogen atom or a methyl group, and R ６ , R ７ , R ８ are each independently a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and Y ２ is NH or an oxygen atom, and k and l each independently represent an integer of 1 to 5. [5] The non-specific reaction inhibitor according to any one of [2] to [4], wherein A in the formula (1) is a linear or branched alkyl group having 12 to 28 carbon atoms. [6] R in the formula (2) ３ and R ４ [7] The non-specific reaction inhibitor according to [4] or [5], wherein R in the formula (3) is a methyl group. ６ , R７ and R ８ is a methyl group, and k and l are 2. [8] The non-specific reaction inhibitor according to any one of [1] to [7], wherein the copolymer further contains a third repeating unit having a molecular weight of 1,000 or less. [9] The non-specific reaction inhibitor according to [8], wherein the third repeating unit is a repeating unit formed by any one monomer selected from the group consisting of (meth)acrylic acid, methyl (meth)acrylate, 2-methoxyethyl acrylate, and vinylpyrrolidone.

[10] The non-specific reaction inhibitor according to any one of [1] to [9], wherein the antibody or fragment thereof is at least one selected from the group consisting of an antibody against an immunoglobulin or a fragment thereof, an anti-M protein antibody, an anti-cryoglobulin antibody, an anti-pyroglobulin antibody, an anti-rheumatoid factor antibody, an anti-complement antibody, and a decoy antibody.

[11] The non-specific reaction inhibitor according to

[10] , wherein the immunoglobulin or a fragment thereof is an immunoglobulin or a fragment thereof derived from any one animal selected from the group consisting of human, mouse, rat, rabbit, cow, goat, sheep, alpaca, dog, cat, and bird.

[12] The non-specific reaction inhibitor according to any one of [1] to

[11] , wherein the antibody or a fragment thereof is an antibody or a fragment thereof derived from any one animal selected from the group consisting of mouse, rat, rabbit, cow, goat, sheep, and alpaca.

[13] The non-specific reaction inhibitor according to any one of [1] to

[12] , wherein the antibody or a fragment thereof is an antibody or a fragment thereof derived from a mouse.

[14] The non-specific reaction inhibitor according to any one of [1] to

[13] , wherein the antibody or a fragment thereof is an antibody or a fragment thereof modified with a polymer compound.

[0009]

[15] A non-specific reaction suppression method, comprising mixing the non-specific reaction suppressor according to any one of [1] to

[14] with a biological sample, and suppressing a non-specific reaction of a target substance contained in the biological sample when measuring the target substance.

[0010]

[16] A reagent for use in biochemical measurements, the reagent comprising (a) an antibody or a fragment thereof, and (b) a copolymer comprising (1) a first repeating unit having a linear or branched alkyl group having 12 to 40 carbon atoms, and (2) a second repeating unit having a cationic moiety and an anionic moiety.

[17] The reagent for biochemical measurements according to

[16] , wherein the first repeating unit has a structure represented by formula (1): (In formula (1), R １ is a hydrogen atom or a methyl group, X is NH or an oxygen atom, and A is a linear or branched alkyl group having 12 to 40 carbon atoms.)

[18] The reagent for biochemical measurements according to

[16] or

[17] , wherein the cationic site of the second repeating unit is a quaternary ammonium group.

[19] The reagent for biochemical measurements according to any one of

[16] to

[18] , wherein the second repeating unit has a structure represented by formula (2) and / or formula (3). (In formula (2), R ２ is a hydrogen atom or a methyl group, and R ３ and R ４ are each independently a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and Y １ is an NH or oxygen atom, and Z is SO ３ － or COO － wherein n and m are each independently an integer of 1 to 5. (In formula (3), R ５ is a hydrogen atom or a methyl group, and R ６ , R ７ , R ８ are each independently a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and Y ２ is NH or an oxygen atom, and k and l each independently represent an integer of 1 to 5.

[20] The reagent for biochemical measurements according to

[17] , wherein A in the formula (1) is a linear or branched alkyl group having 12 to 28 carbon atoms.

[21] R in the formula (2) ３ and R ４

[22] The reagent for biochemical measurement according to

[19] , wherein R in formula (3) is a methyl group. ６ , R ７ and R ８is a methyl group, and k and l are 2.

[23] The reagent for biochemical measurements according to any one of

[16] to

[22] , wherein the copolymer further comprises a third repeating unit having a molecular weight of 1,000 or less.

[24] The reagent for biochemical measurements according to

[23] , wherein the third repeating unit is a repeating unit formed by any one monomer selected from the group consisting of (meth)acrylic acid, methyl (meth)acrylate, 2-methoxyethyl acrylate, and vinylpyrrolidone.

[25] The reagent for biochemical measurements according to any one of

[16] to

[24] , wherein the antibody or fragment thereof is at least one selected from the group consisting of an antibody against an immunoglobulin or a fragment thereof, an anti-M protein antibody, an anti-cryoglobulin antibody, an anti-pyroglobulin antibody, an anti-rheumatoid factor antibody, an anti-complement antibody, and a decoy antibody.

[26] The reagent for biochemical measurements according to

[25] , wherein the immunoglobulin or a fragment thereof is an immunoglobulin or a fragment thereof derived from any one animal selected from the group consisting of human, mouse, rat, rabbit, cow, goat, sheep, alpaca, dog, cat, and bird.

[27] The reagent for biochemical measurements according to any one of

[16] to

[26] , wherein the antibody or a fragment thereof is an antibody or a fragment thereof derived from any one animal selected from the group consisting of mouse, rat, rabbit, cow, goat, and alpaca.

[28] The reagent for biochemical measurements according to any one of

[16] to

[27] , wherein the antibody or a fragment thereof is an antibody or a fragment thereof derived from a mouse.

[29] The reagent for biochemical measurements according to any one of

[16] to

[28] , wherein the antibody or a fragment thereof is an antibody or a fragment thereof modified with a polymer compound.

[30] The reagent for biochemical measurements according to any one of

[16] to

[29] , wherein the biochemical measurement is performed by a homogeneous method.

[31] The reagent for biochemical measurement according to any one of

[16] to

[30] , wherein the biochemical measurement is a measurement based on an antigen-antibody reaction.

[32] The reagent for biochemical measurement according to any one of

[16] to

[31] , wherein the biochemical measurement is a latex immunoturbidimetric method.

[0011]

[33] A reagent for use in biochemical measurements, comprising (a) an antibody or a fragment thereof, and (b) a copolymer as a non-specific reaction inhibitor, the copolymer including (1) a first repeating unit having a linear or branched alkyl group having 12 to 40 carbon atoms, and (2) a second repeating unit having a cationic moiety and an anionic moiety. This reagent for biochemical measurements may be the reagent for biochemical measurements described in any one of

[16] to

[32] .

[0012]

[34] A reagent kit for biochemical measurements, comprising the reagent for biochemical measurements according to any one of

[16] to

[33] .

[0013]

[35] A biochemical measurement method comprising the following steps (1) to (4): (1) mixing a measurement sample containing a substance to be measured with a non-specific reaction inhibitor containing an antibody or a fragment thereof as an active ingredient, (2) mixing a measurement sample containing the substance to be measured with a non-specific reaction inhibitor containing, as an active ingredient, a copolymer including (i) a first repeating unit having a linear or branched alkyl group having 12 to 40 carbon atoms, and (ii) a second repeating unit having a cationic moiety and an anionic moiety, (3) adding an antibody specific to the substance to be measured, and (4) detecting a signal resulting from the reaction of the substance to be measured with the specific antibody.

[36] The biochemical measurement method according to

[35] , wherein the copolymer is the copolymer according to any one of [2] to [9].

[37] The biochemical measurement method according to

[35] or

[37] , wherein the antibody or fragment thereof is the antibody or fragment thereof according to any one of

[10] to

[14] .

[0014] According to the above aspects, it is possible to provide a non-specific reaction inhibitor, a non-specific reaction inhibition method, a reagent for biochemical measurement, a reagent kit for biochemical measurement, and a biochemical measurement method.

[0015] The phrase "suppressing nonspecific reactions" used herein means reducing nonspecific reactions originating from the sample, which may occur for some reason, so that the measured value approaches the original measured value (true value). For a target component for which a standard measurement method exists, the true value is the measurement value obtained by the standard measurement method. For a target component for which no standard measurement method exists, measurements using a heterogeneous method (a measurement method that includes a washing step or B / F separation step during measurement) are generally considered to be less likely to cause nonspecific reactions than homogeneous methods (a measurement method that does not include a washing step or B / F separation step during measurement). Even heterogeneous methods may be affected by nonspecific reactions and may fail to obtain true values. In such cases, the sample may be diluted with a component that does not contain the target component, such as saline, and then remeasured to determine whether the measured value corresponds to the dilution ratio, thereby determining the extent of the influence of nonspecific reactions. To suppress nonspecific reactions, a method of covering all components involved in the reaction with some kind of component may be considered. For example, this applies when a non-specific adsorption inhibitor is used, but in this case, the desired biochemical reaction may not occur easily, resulting in a decrease in measurement sensitivity. In this specification, it is intended to suppress non-specific reactions without causing such a decrease in measurement sensitivity.

[0016] 1 shows the correlation between the measurement values ​​of the LTIA reagent for measuring sIL-2R in Comparative Example 6 and the measurement values ​​of an approved reagent. 2 shows the correlation between the measurement values ​​of the LTIA reagent for measuring sIL-2R in Example 5 and the measurement values ​​of an approved reagent. 3 shows the correlation between the measurement values ​​of the LTIA reagent for measuring sIL-2R in Comparative Example 6 and the measurement values ​​of an approved reagent. 4 shows the correlation between the measurement values ​​of the LTIA reagent for measuring sIL-2R in Example 5 and the measurement values ​​of an approved reagent.

[0017] <Non-specific reaction inhibitor> (First embodiment) The non-specific reaction inhibitor of this embodiment contains, as active ingredients, an antibody or a fragment thereof, and a copolymer including (1) a first repeating unit having a linear or branched alkyl group having 12 to 40 carbon atoms, and (2) a second repeating unit having a cationic moiety and an anionic moiety. Here, the term "polymer" may be interchangeable with "polymer." Furthermore, the term "copolymer" may be interchangeable with "copolymer."

[0018] (Antibody or Fragment Thereof) The antibody or fragment thereof of this embodiment can be any antibody or fragment thereof that specifically binds to a substance that induces a nonspecific reaction (hereinafter also referred to as a nonspecific reaction-causing substance) and thereby inhibits the nonspecific reaction of the substance in a biochemical measurement system. Specific examples include antibodies against immunoglobulins or fragments thereof, anti-M protein antibodies, anti-cryoglobulin antibodies, anti-pyroglobulin antibodies, anti-rheumatoid factor antibodies, anti-complement antibodies, and decoy antibodies. Among these, antibodies selected from the group consisting of antibodies against immunoglobulins or fragments thereof, anti-rheumatoid factor antibodies, anti-complement antibodies, and decoy antibodies are preferred. The antibody exhibiting the nonspecific reaction-inhibiting effect may be a polyclonal antibody or a monoclonal antibody. Furthermore, the antibody exhibiting the nonspecific reaction-inhibiting effect may be a recombinant antibody produced by introducing the monoclonal antibody gene into an appropriate host or host cell using genetic engineering technology. Monoclonal antibodies or recombinant antibodies are preferred because there is little difference in performance due to differences in production lots.

[0019] (Monoclonal antibody) As used herein, the term "monoclonal antibody" refers to an antibody or antibody molecule obtained from a single antibody-producing cell. In the present invention, an antibody fragment (also referred to as an antigen-binding fragment) having the antigen-binding activity of this monoclonal antibody can also be used, as long as the effects of the present invention are obtained. The antibody fragment having the antigen-binding activity of a monoclonal antibody may be any antibody fragment as long as it has antigen-binding activity, and examples thereof include antigen-binding fragments containing the Fab portion of the monoclonal antibody obtained by enzymatic digestion of the monoclonal antibody, and Fab, Fab', and F(ab') containing the antigen-binding fragment of the monoclonal antibody produced by genetic recombination. ２ , scFv, Fv fragments, and VHH fragments.

[0020] (Antibodies against immunoglobulins or fragments thereof) In the present invention, an embodiment of the immunoglobulin or fragment thereof includes an immunoglobulin or fragment thereof derived from a human. Furthermore, the immunoglobulin or fragment thereof is preferably an immunoglobulin or fragment thereof derived from the same animal species as the specific antibody against the substance to be measured. Examples of animal species include mouse, rat, rabbit, cow, goat, sheep, and alpaca. Furthermore, the immunoglobulin or fragment thereof may be an immunoglobulin or fragment thereof derived from any animal selected from dog, cat, and bird.

[0021] Examples of immunoglobulins include immunoglobulin M (IgM), immunoglobulin A (IgA), immunoglobulin G (IgG), immunoglobulin D (IgD), immunoglobulin E (IgE), and immunoglobulin Y (IgY) produced in the egg yolk of birds. The recognition site of the immunoglobulin to which the antibody or the like used in the present invention binds may be the entire immunoglobulin, a variable region, Fc, a heavy chain (H chain), a light chain (L chain), or a partial fragment of any of them. In the case of a light chain (L chain), it may be either a κ chain or a λ chain.

[0022] As the antibody exhibiting the nonspecific reaction inhibitory effect used in the present invention, any antibody can be used as long as it can inhibit nonspecific reactions by binding to the aforementioned immunoglobulin. Specific examples include anti-human IgM antibodies, anti-human IgA antibodies, anti-human IgG antibodies, anti-human IgL (κ chain) antibodies, and anti-human IgL (λ chain) antibodies (International Publication No. WO 2024 / 048583). Other known antibodies include anti-mouse IgG antibodies, anti-dog IgM antibodies (JP 2019-140987 A), anti-cat IgM antibodies (International Publication No. WO 2018-203572 A), and anti-avian IgY antibodies (JP 2012-47481 A). These antibodies are preferably used as nonspecific reaction inhibitors. It is also preferable to use heterophile antibody interference inhibitors as nonspecific reaction inhibitors. Heterophilic antibodies are a general term for human antibodies that exhibit reactivity with animal-derived antibodies, which are the main components of immunological assays. HAMA (human anti-mouse immunoglobulin antibody) is known as a representative example. Commercially available heterophilic antibody interference inhibitors include Heteroblock (registered trademark), manufactured by Omega Biologicals, and HBR-1 (manufactured by Scantibodies Laboratory).

[0023] (Anti-rheumatoid factor antibody) Rheumatoid factor (RF) is an autoantibody against the Fc of IgG. There are five types of RF: IgG, IgA, IgM, IgD, and IgE, with the most common being IgM. As a nonspecific reaction inhibitor, it is preferable to use an antibody against IgM RF.

[0024] (Anti-M protein antibody) M protein is a monoclonal immunoglobulin. When plasma cells become cancerous, the corresponding monoclonal immunoglobulin and its partial structures are produced in large quantities, resulting in an abnormal increase in blood concentration. Depending on the antibody class, M protein types include immunoglobulin molecules such as IgG, IgA, IgM, IgD, and IgE, as well as partial structures such as heavy chain gamma chains, alpha chains, mu chains, delta chains, and epsilon chains, light chain kappa chains and lambda chains, and half-molecular immunoglobulins. Anti-M protein antibodies can be used as non-specific reaction inhibitors.

[0025] (Anti-cryoglobulin antibody) Cryoglobulin is an immunoglobulin that has the property of precipitating at temperatures below 37° C. (body temperature) and redissolving when heated back to 37° C. Anti-cryoglobulin antibody can be used as a non-specific reaction inhibitor.

[0026] (Anti-pyroglobulin antibody) Pyroglobulin is a temperature-dependent protein, an abnormal immunoglobulin that gels when heated at around 56°C for 30 minutes and does not dissolve again even when heated to 100°C or returned to room temperature. Anti-pyroglobulin antibody can be used as a non-specific reaction inhibitor.

[0027] (Anti-complement antibody) Complement is a collective term for a group of proteins that assist antibodies and phagocytes when the body eliminates pathogens, and there are C1 to C8. Known anti-complement antibodies as non-specific reaction inhibitors include anti-C1 antibody, anti-C2 antibody (International Publication No. WO2024 / 004805), and anti-C3 antibody (International Publication No. WO2022 / 163605). In the present invention, these can be used alone or in combination.

[0028] (Decoy antibody) In this specification, the term "decoy antibody" refers to an antibody that has a similar structure to a specific antibody for the substance to be measured (antigen), but in which the binding activity of the specific antibody for the antigen is reduced or absent. In the absence of a decoy antibody, the substance that causes the nonspecific reaction binds to the specific antibody and causes the nonspecific reaction. In contrast, in the presence of a decoy antibody, the substance that causes the nonspecific reaction is made to react with the decoy antibody, making it unreactive with the specific antibody, thereby suppressing the nonspecific reaction.

[0029] Such a decoy antibody can be an antibody, as disclosed in Japanese Patent Application Laid-Open No. 9-288108, which is a conjugate obtained using the same antibody molecule and / or antibody fragment as the antibody used for the labeled antibody, and in which the specific antigen-binding activity of the antibody has been reduced or completely or substantially lost. Methods for losing the antigen-binding activity of an antibody include known methods such as heat treatment, enzymatic degradation, chemical treatment with acid, alkali, or reducing agent, and ultrasonic treatment.

[0030] Furthermore, as disclosed in International Publication WO 2023 / 127881, modified antibodies can be used in which part or all of the variable regions of the L chain and / or H chain of a specific antibody have been modified by genetic engineering techniques. The term "modified" is used to encompass any of substitution, deletion, and addition. Specifically, such modified antibodies include modified antibodies in which part or all of the regions (generally CDRs) that are particularly involved in antigen-antibody reactions within the variable regions of the L chain and / or H chain of a specific antibody have been modified, or modified antibodies in which part or all of the regions involved in the three-dimensional structure of the CDRs have been modified. It is desirable that the modified regions in modified antibodies be as small as possible. Examples of regions involved in the three-dimensional structure of the CDRs include the regions adjacent to the N-terminus and / or C-terminus of the amino acid sequence of each CDR, and regions that interact with the three-dimensional structure of each CDR. Decoy antibodies can be produced using any of the above methods, or by combining these methods.

[0031] (Method for Preparing Monoclonal Antibodies) Monoclonal antibodies can be prepared by dissolving the above-mentioned mammalian immunoglobulin or fragments thereof, rheumatoid factor, complement, or the like as an antigen (also referred to as an immunogen) in a solvent such as phosphate-buffered saline, and administering this solution to a non-human animal for immunization. If necessary, an appropriate adjuvant may be added to the solution, and the resulting emulsion may be used for immunization. Examples of adjuvants that can be used include commonly used adjuvants such as water-in-oil emulsions, water-in-oil-in-water emulsions, oil-in-water emulsions, liposomes, and aluminum hydroxide gel, as well as proteins or peptide substances derived from biological components. For example, Freund's incomplete adjuvant or Freund's complete adjuvant can be suitably used. The administration route, dosage, and timing of the adjuvant are not particularly limited, but are desirably selected appropriately to enhance the desired immune response in the animal immunized with the antigen.

[0032] The type of animal used for immunization is not particularly limited, but mammals such as mice, rats, cows, rabbits, goats, sheep, alpacas, mice, or rats are preferred. Mice, rats, or rabbits are more preferred, and mice are particularly preferred. Animal immunization can be carried out according to a conventional method, for example, by injecting a solution of an antigen, preferably a mixture with an adjuvant, into the animal subcutaneously, intradermally, intravenously, or intraperitoneally. Since immune responses generally vary depending on the type and strain of the animal being immunized, it is desirable to appropriately set the immunization schedule depending on the animal used. It is preferable to repeat antigen administration several times after the initial immunization.

[0033] To obtain the monoclonal antibody of the present invention, the following procedures can be subsequently carried out, but are not limited to these. Methods for producing monoclonal antibodies themselves are well known and widely used in the art. Therefore, those skilled in the art can prepare the monoclonal antibody of the present invention by using the above-mentioned antigen (see, for example, Chapter 6 of "Antibodies, A Laboratory Manual" (Cold Spring Harbor Laboratory Press, (1988)).

[0034] After the final immunization, antibody-producing spleen cells or lymph node cells are extracted from the immunized animal and fused with a myeloma-derived cell line with high proliferation potential to produce hybridomas. For cell fusion, it is preferable to use cells with high antibody production capacity (quality and quantity). It is also more preferable that the myeloma-derived cell line is compatible with the animal from which the antibody-producing cells to be fused are derived. Cell fusion can be performed using methods known in the art. For example, the polyethylene glycol method, a method using Sendai virus, or a method using electric current can be used. The obtained hybridomas can be grown under conditions commonly used in the art. The desired hybridomas can be selected while confirming the properties of the produced antibodies. Hybridoma cloning can be performed using well-known methods, such as limiting dilution and soft agar.

[0035] After the cloning step, the binding ability of the produced monoclonal antibodies to the antigen can be assayed using methods such as ELISA, RIA, or fluorescent antibody assay, etc. These procedures can confirm whether the selected hybridomas produce monoclonal antibodies with the desired properties.

[0036] Monoclonal antibodies with desired characteristics can be produced by mass-culturing the hybridomas selected as described above. The mass-culturing method is not particularly limited, but examples include culturing hybridomas in an appropriate medium to produce monoclonal antibodies in the medium, and injecting hybridomas into the abdominal cavity of a mammal to grow them and produce monoclonal antibodies in the ascites. Monoclonal antibodies can also be produced using insects such as silkworms. In addition to the method of producing antibodies by immunizing animals as described above, desired antibodies can also be produced using phage display methods, which do not require animal immunization. Furthermore, the genes of the monoclonal antibodies obtained in this manner can be introduced into host cells using genetic recombination techniques to produce recombinant antibodies, which can then be used as nonspecific reaction inhibitors.

[0037] (Modification of Antibodies) The antibodies or fragments thereof obtained as described above can be modified with any compound before use. The compound can be selected from the group of polymeric compounds consisting of polysaccharides, proteins, and organic polymers, for example, polyethylene glycol. Methods for chemically modifying proteins with polymers are known. The main methods are described in the reviews by Roberts M. J. et al. (Advanced Drug Delivery Reviews 2002, 54, 459-476) and Francesco M. et al. (Biomaterials 2001, 22, 405-417). For example, methods of conjugating a polymer targeting the amino group in the side chain of an amino acid constituting a protein, the thiol group of a cysteine ​​residue, the carboxyl group at the carboxyl terminal, or the amino group at the amino terminal, or the hydroxyl group of a serine or threonine residue, etc., have been mentioned. Methods for binding polymers to antibodies or antibody fragments are also known. In particular, when chemically modifying antibodies, it is considered useful to prepare chemically modified antibodies using a method that does not eliminate the antigen-binding ability.

[0038] (Modification of Nonspecific Reaction-Inhibiting Antibodies) The antibodies or fragments thereof obtained as described above can also be used as chimeric antibodies by recombining them with the constant region of another animal species. For example, the constant region of a mouse anti-human IgM antibody obtained by immunizing a mouse can be modified to that of a rabbit to be used as an anti-human IgM rabbit-mouse chimeric antibody. Taking into consideration the animal species from which the specific antibody to be used in immunological assays is produced, those skilled in the art can appropriately chimerize the antibody and use it.

[0039] (Copolymer) The copolymer of this embodiment is a copolymer containing (1) a first repeating unit having a linear or branched alkyl group having 12 to 40 carbon atoms, and (2) a second repeating unit having a cationic moiety and an anionic moiety. Here, the "repeating unit" may be referred to as a segment.

[0040] (First Repeating Unit) The polymerizable group of the monomer that becomes the first repeating unit is preferably a polymerizable group having a carbon-carbon double bond. Examples of the linear or branched alkyl group having 12 to 40 carbon atoms include linear alkyl groups having 12 to 40 carbon atoms and branched alkyl groups having at least one branch point and having a total carbon number of 12 to 40 in the main chain and each branch chain. The branched alkyl group may have 1 to 5 branch points, or preferably 1 to 3 branch points, and more preferably 1 branch point.

[0041] A more specific example of the structure of the first repeating unit is a structure represented by formula (1).

[0042] (In formula (1), R １ is a hydrogen atom or a methyl group, X is an NH or an oxygen atom, and A is a linear or branched alkyl group having 12 to 40 carbon atoms.

[0043] (In formula (4), R ９ is a hydrogen atom or a methyl group, Z is an NH or an oxygen atom, and R １０ , R １１ are each independently a linear or branched alkyl group having 1 to 30 carbon atoms, and R １０ and R １１ The total number of carbon atoms is 10 to 38.

[0044] R １ is a hydrogen atom or a methyl group. X is NH (i.e., an -NH- group) or an oxygen atom. A is a linear or branched alkyl group having 12 to 40 carbon atoms, preferably 12 to 28 carbon atoms. When A is a linear alkyl group, A preferably has 12 to 40 carbon atoms, more preferably 12 to 28 carbon atoms, and even more preferably 12 to 22 carbon atoms. When A is a branched alkyl chain, A preferably has 12 to 40 carbon atoms, more preferably 12 to 30 carbon atoms. Furthermore, when A is a branched alkyl chain, the structure shown in formula (4) is preferred. In formula (4), R ９ is a hydrogen atom or a methyl group, and Z is an NH or an oxygen atom. １０ , R １１are each independently preferably a linear or branched alkyl group having 1 to 30 carbon atoms, more preferably 8 to 22 carbon atoms, and particularly preferably 10 to 14 carbon atoms. １０ and R １１ The total number of carbon atoms in A is preferably 10 to 38, more preferably 20 to 30, and particularly preferably 22 to 26. When A is a linear or branched alkyl group having 12 to 40 carbon atoms, the effect of suppressing non-specific reactions is high.

[0045] Specific examples of the first repeating unit, when A is a linear alkyl group and Z is an oxygen atom, are preferably lauryl (meth)acrylate, tetradecyl (meth)acrylate, cetyl (meth)acrylate, stearyl (meth)acrylate, oleyl (meth)acrylate, icosyl (meth)acrylate, and behenyl (meth)acrylate. Furthermore, lauryl (meth)acrylate, stearyl (meth)acrylate, and behenyl (meth)acrylate are even more preferable. Furthermore, when A of the first repeating unit is a linear alkyl group and Z is NH, are preferably lauryl (meth)acrylamide, tetradecyl (meth)acrylamide, cetyl (meth)acrylamide, stearyl (meth)acrylamide, oleyl (meth)acrylamide, icosyl (meth)acrylamide, and behenyl (meth)acrylamide. Furthermore, lauryl (meth)acrylamide, stearyl (meth)acrylamide, and behenyl (meth)acrylamide are even more preferable. When A is a branched alkyl chain, the structure shown in formula (4) is preferred. １０ is a linear alkyl group having 10 carbon atoms, R １１ is a linear alkyl group having 12 carbon atoms), dodecylhexadecyl methacrylate (R １０ is a linear alkyl group having 12 carbon atoms, R １１ is a linear alkyl group having 14 carbon atoms).

[0046] When the first repeating unit has the structure of formula (1), the copolymer has a peak at 2870 to 2833 cm in a spectrum of Fourier transform infrared spectroscopy by attenuated total reflectance (ATR) measurement.－１ When a repeating unit having a peak in this range is contained in a copolymer, the effect of suppressing non-specific reactions is high (see the pamphlet of International Publication No. WO2024 / 075847).

[0047] (Infrared absorption spectrum) An infrared absorption spectrum is a graph that shows the vibrational frequencies specific to each functional group that are generated from each functional group in a molecule when the molecule is irradiated with infrared light. In the present invention, the infrared absorption spectrum is a value measured by Fourier transform infrared spectroscopy (FT-IR) analysis using an attenuated total reflectance (ATR) method. The infrared absorption spectrum has transmittance (%) on the vertical axis and wavenumber (unit: cm) on the horizontal axis. －１ ) and is shown as a graph of a curve connecting successive measured values. When there is a peak with maximum absorption in a specific wavenumber range, the graph changes from decreasing to increasing at that peak.

[0048] The infrared absorption spectrum values ​​described in this specification are based on values ​​measured using the following equipment and measurement conditions. The same measurement results can be obtained by using a measurement equipment with performance equivalent to or better than those listed below and applying equivalent measurement conditions. <Measurement equipment> Thermo Scientific Nicolet™ iS5 FT-IR <Measurement conditions> Crystal: Diamond Incident angle: 45° Correction: None

[0049] The infrared absorption spectrum of the copolymer is 3000 to 2800 cm －１ There can be two maximum absorption peaks. When there are two maximum absorption peaks in this range, the wavenumber ranges of the peak on the high wavenumber side (hereinafter sometimes referred to as P1) and the peak on the low wavenumber side (hereinafter sometimes referred to as P2) are as follows: P1 is 3000 to 2880 cm －１ The absorption maximum of P1 appears at 2946-2906 cm －１ , preferably 2936 to 2916 cm －１ P2 is in the range of 2879 to 2800 cm －１ The absorption maximum of P2 appears at 2870-2833 cm －１ , preferably 2865 to 2833 cm －１, more preferably 2863 to 2843 cm －１ The range is as follows. The number of peaks having an absorption maximum in the range of P1 or the range of P2 is not particularly limited, taking into consideration that it may be affected by the resolution of the infrared absorption spectrometer, but is preferably 1 to 5, more preferably 1 to 3, even more preferably 1 to 2, and particularly preferably 1. The transmittance (%) at the absorption maximum may be P1 > P2, or P1 = P2, or P1 ≈ P2, or may be P1 < P2. It is preferable that P1 < P2.

[0050] Generally, 3000 to 2800 cm －１ The region is CH stretching, CH ２ Symmetric stretching, CH ３ Symmetric stretching, CH ２ Antisymmetric stretching, CH ３ This is the region where the peaks of antisymmetric stretching appear, and it is presumed that P1 and P2 belong to one of these. ２ Symmetrical stretching is 2853 cm －１ Nearby, CH ２ The antisymmetric stretch is 2926 cm －１ There is a peak in the vicinity of 3000-2800 cm (Spectroscopic Identification of Organic Compounds, 8th Edition, Tokyo Kagaku Dojin Publishing, 2016, p. 84). Generally, the peak of the infrared absorption spectrum shifts depending on the surrounding molecular structure. －１ For the region, the peak fluctuation is approximately ±10 cm －１ It is said to be within the range of

[0051] (Second Repeating Unit) The cationic moiety of the second repeating unit may be directly bonded to the polymerizable group of the monomer that becomes the second repeating unit, or may exist as a partial structure of a substituent bonded to the polymerizable group. The polymerizable group is preferably a polymerizable group having a carbon-carbon double bond. When the cationic moiety is a partial structure of a substituent, it may be present in the middle of the substituent or at the end of the substituent. The anionic moiety may be directly bonded to the polymerizable group, or may exist as a partial structure of a substituent bonded to the polymerizable group. When the anionic moiety is a partial structure of a substituent, it may be present in the middle of the substituent or at the end of the substituent. The cationic moiety and the anionic moiety may be adjacent to each other or may be separated from each other. A structure having both a cationic moiety and an anionic moiety is also called a zwitterion. The second repeating unit can also be said to have a zwitterionic structure.

[0052] Examples of the cationic moiety include a quaternary ammonium group and a sulfonium group, with a quaternary ammonium group being preferred. Examples of the anionic moiety include a sulfo group, a carboxy group, a phosphoryl group, and an oxide group, with a sulfo group, a carboxy group, and a phosphoryl group being preferred. Examples of structures having both a cationic moiety and an anionic moiety include sulfobetaine, carbobetaine, phosphorylcholine (phosphobetaine), dimethylamine oxide, and dimethylsulfoniopropionate. Among these, sulfobetaine, carbobetaine, and phosphorylcholine are preferred.

[0053] A more specific example of the structure of the second repeating unit is a structure represented by formula (2) or (3).

[0054] (In formula (2), R ２ is a hydrogen atom or a methyl group, and R ３ and R ４ are each independently a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and Y １ is an NH or oxygen atom, and Z is SO ３ － or COO － wherein n and m are each independently an integer of 1 to 5.

[0055] (In formula (3), R ５ is a hydrogen atom or a methyl group, and R ６ , R ７ , R ８ are each independently a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and Y ２ is NH or an oxygen atom, and k and l each independently represent an integer of 1 to 5.

[0056] In formula (2), R ２ is a hydrogen atom or a methyl group. ３ and R ４ are each independently a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and a methyl group is preferred. １ is an NH or oxygen atom, and Z is SO ３ － or COO － n and m each independently represent an integer of 1 to 5, and preferably an integer of 1 to 4.

[0057] Specific examples of the second repeating unit represented by formula (2) include 4-[(3-methacrylamidopropyl)dimethylammonio]butane-1-sulfonic acid, 3-[[2-(methacryloyloxy)ethyl]dimethylammonio]propane-1-sulfonic acid, 2-[[2-(methacryloyloxy)ethyl]dimethylammonio]acetic acid, 3-[[2-(methacryloyloxy)ethyl]dimethylammonio]propionate, 3-[[2-(acryloyloxy)ethyl]dimethylammonio ]propane-1-sulfonic acid, 4-[[2-(methacryloyloxy)ethyl]dimethylammonio]butane-1-sulfonic acid, 3-[(3-methacrylamidopropyl)dimethylammonio]propane-1-sulfonic acid, 3-[(3-acrylamidopropyl)dimethylammonio]propane-1-sulfonic acid, 2-[[2-(methacryloyloxy)ethyl]dimethylammonio]acetic acid, 3-[(3-acrylamidopropyl)dimethylammonio]propanoate. Among these, 4-[(3-methacrylamidopropyl)dimethylammonio]butane-1-sulfonic acid, 3-[[2-(methacryloyloxy)ethyl]dimethylammonio]propane-1-sulfonic acid, 3-[[2-(methacryloyloxy)ethyl]dimethylammonio]propionate, or 3-[[2-(acryloyloxy)ethyl]dimethylammonio]propane-1-sulfonic acid is more preferred.

[0058] In formula (3), R ５ is a hydrogen atom or a methyl group. ６ , R ７ , R ８ are each independently a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and a methyl group is preferred. ２ is NH or an oxygen atom, and preferably an oxygen atom. k and l each independently represent an integer of 1 to 5, and preferably both are 2.

[0059] Specific examples of the second repeating unit represented by formula (3) include compounds having a 2-methacryloyloxyethyl phosphorylcholine skeleton, such as 2-(meth)acryloyloxyethyl-2'-(trimethylammonio)ethyl phosphate, 2-(meth)acryloyloxypropyl-2'-(trimethylammonio)ethyl phosphate, 2-(meth)acryloyloxyethoxyethyl-2'-(trimethylammonio)ethyl phosphate, 2-(meth)acryloyloxydiethoxyethyl-2'-(trimethylammonio)ethyl phosphate, and 2-(meth)acryloyloxytriethoxyethyl-2'-(trimethylammonio)ethyl phosphate. Among these, 2-(meth)acryloyloxyethyl-2'-(trimethylammonio)ethyl phosphate is preferred, and 2-methacryloyloxyethyl-2'-(trimethylammonio)ethyl phosphate (sometimes referred to as "2-methacryloyloxyethyl phosphorylcholine" or "MPC") is more preferred because of its easy availability. This compound is represented by the R ５ , R ６ , R ７ and R ８ is a methyl group, and Y ２ is an oxygen atom, and k and l are 2.

[0060] The second repeating unit may have either a structure represented by formula (2) or a structure represented by formula (3), or may have both structures represented by formula (2) and formula (3).

[0061] The copolymer of this embodiment may have a third repeating unit derived from a polymerizable compound having a molecular weight of 1000 or less. Specific examples of the third repeating unit include methyl methacrylate, methyl acrylate, methacrylic acid, 2-methoxyethyl acrylate, vinylpyrrolidone, N-acryloyltris(hydroxymethyl)aminomethane, vinylphosphonic acid, acrylic acid, acrylamide, methacrylamide, potassium 3-sulfopropyl acrylate, sodium 2-methyl-2-[(1-oxo-2-propenyl)amino]-1-propanesulfonate, 2-acrylamido-2-methylpropanesulfonic acid, sodium methacrylate, sodium acrylate, 2-methoxyethyl acrylate, 3-methoxypropyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, isobutyl acrylate, cyclohexyl acrylate, 1-methylcyclopentyl acrylate, phenyl acrylate, benzyl acrylate, 2-(dimethylamino)ethyl acrylate, 2-(diethylamino)ethyl acrylate, and potassium acrylate. ammonium, mono(2-acryloyloxyethyl) succinate, 2-hydroxyethyl acrylate, 4-hydroxybutyl acrylate, 2-(2-oxopyrrolidin-1-yl)ethyl acrylate, glycidyl acrylate, 2-cyanoethyl acrylate, 2-methoxyethyl methacrylate, 2-ethoxyethyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, isobutyl methacrylate, cyclohexyl methacrylate, methacrylate 1-methylcyclopentyl methacrylate, 2-oxotetrahydrofuran-3-yl methacrylate, 5-oxotetrahydrofuran-3-yl methacrylate, phenyl methacrylate, benzyl methacrylate, furfuryl methacrylate, 2-aminoethyl methacrylate hydrochloride, 2-(dimethylamino)ethyl methacrylate, 2-(diethylamino)ethyl methacrylate, 2-(tert-butylamino)ethyl methacrylate, 2-(methacryloyloxy)-N,N,N-Trimethylethanaminium methylsulfate, 1-[2-(methacryloyloxy)ethyl] succinate, 2-hydroxyethyl methacrylate, methacryloylcholine chloride, 2-morpholinoethyl methacrylate, 2-(2-oxopyrrolidin-1-yl)ethyl methacrylate, glycidyl methacrylate, potassium 3-sulfopropyl methacrylate, 2-hydroxyethyl methacrylic acid phosphate, N,N-dimethylacrylamide, N,N-diethylacrylamide, N-isopropylacrylamide, N-propylacrylamide, N-butylacrylamide, 3-acryloyl-2-oxazolidinone, N-phenylacrylamide, N-benzylacrylamide, N-(methoxymethyl)acrylamide, N-(isobutoxymethyl)acrylamide, N-(butoxymethyl)acrylamide, N-[3-(dimethylamino)propyl]acrylamide, N-[2-(dimethylamino)ethyl] Examples of suitable compounds include acrylamide, N-[2-(diethylamino)ethyl]acrylamide, 6-acrylamidohexanoic acid, (3-acrylamidopropyl)trimethylammonium chloride, N-(hydroxymethyl)acrylamide, N-(2-hydroxyethyl)acrylamide, N-(2-amino-2-oxoethyl)acrylamide, N-methylmethacrylamide, N,N-dimethylmethacrylamide, N-isopropylmethacrylamide, N-phenylmethacrylamide, N-(methoxymethyl)methacrylamide, N-(3-aminopropyl)methacrylamide hydrochloride, N-(3-dimethylaminopropyl)methacrylamide, N-[2-(dimethylamino)ethyl]methacrylamide, N-(hydroxymethyl)methacrylamide, N-(2-hydroxypropyl)methacrylamide, maleic acid, fumaric acid, itaconic acid, citraconic acid, maleic anhydride, itaconic anhydride, and citraconic anhydride. Among these, repeating units derived from one or more of methyl methacrylate, methyl acrylate, methacrylic acid, 2-methoxyethyl acrylate, and vinylpyrrolidone are preferred, and repeating units derived from methyl methacrylate are more preferred. The inclusion of a third repeating unit may enhance solubility. Furthermore, the inclusion of a third repeating unit may enhance the effect of suppressing non-specific reactions.

[0062] The weight-average molecular weight of the copolymer is preferably 1,000 to 5,000,000, more preferably 1,000 to 1,000,000, and particularly preferably 1,000 to 500,000. When the weight-average molecular weight is 1,000 or more, the affinity with non-specific reaction substances is increased, making it easier for the copolymer to fully exert its effect as a non-specific reaction inhibitor. Furthermore, when the weight-average molecular weight is 5,000,000 or less, the viscosity of the reagent according to the present invention containing the copolymer is prevented from becoming too high, making it easier for the intended measurement to be carried out smoothly.

[0063] The weight-average molecular weight of the copolymer is measured by gel filtration chromatography, and reference can be made to the pamphlet of International Publication No. WO 2022 / 124288. Specifically, the weight-average molecular weight can be measured by gel filtration chromatography under the following conditions using polyethylene oxide and polyethylene glycol as standard samples. <Measurement device> Device: HLC-8420GPC (manufactured by Tosoh Corporation) Detector: HLC-8420GPC built-in RI detector (manufactured by Tosoh Corporation) Sample column: TSKgel SuperMultiporePW-H (6.0 mm I.D. x 15 cm x 2) (manufactured by Tosoh Corporation) Reference column: TSKgel SuperH-RC (manufactured by Tosoh Corporation) Guard column: TSKgel guardcolumn SuperMP(PW)-H (manufactured by Tosoh Corporation) <Measurement conditions> Eluent: 0.2 M aqueous sodium nitrate solution / methanol = 80 / 20 (volume ratio) Flow rate: 0.4 mL / min Injection volume: 40 μL Column temperature: 40°C Standard samples: polyethylene oxide (Tosoh Corporation), polyethylene glycol (Fujifilm Wako Pure Chemical Industries, Ltd.)

[0064] The molar fraction of the substance amount of the first repeating unit relative to the substance amount of all repeating units constituting the copolymer, when the total of the first repeating unit and the other repeating units is taken as 100 mol %, can be 1 to 50 mol %, can be 1 to 40 mol %, and is more preferably 3 to 40 mol %. When the molar fraction of the substance amount of the first repeating unit relative to the substance amount of all repeating units constituting the copolymer is 1 to 50 mol %, a high effect of suppressing nonspecific reactions can be obtained. Note that the molar fraction is equivalent to the blending ratio of each monomer during polymerization of the copolymer.

[0065] The molar fraction of the substance amount of the second repeating unit relative to the substance amount of all repeating units constituting the copolymer, when the total of the second repeating unit and the other repeating units is taken as 100 mol %, can be 50 to 99 mol %, preferably 60 to 97 mol %, and more preferably 60 to 85 mol %. When the molar fraction of the substance amount of the second repeating unit relative to the substance amount of all repeating units constituting the copolymer is 50 to 99 mol %, a high effect of suppressing nonspecific reactions can be obtained. In addition, the improved water solubility of the copolymer makes it easier to handle.

[0066] The molar fraction of the amount of substance of the third repeating unit relative to the amount of substance of all repeating units constituting the copolymer is preferably 0 to 49 mol %, and more preferably 1 to 25 mol %, with the total amount of the third repeating unit and the other repeating units being 100 mol %. When the molar fraction of the amount of substance of the third repeating unit relative to the amount of substance of all repeating units constituting the copolymer is 0 to 49 mol %, the effect of suitably suppressing nonspecific reactions can be obtained.

[0067] The copolymer of this embodiment can be produced by polymerizing the monomer that will form the first repeating unit, the monomer that will form the second repeating unit, and, if necessary, the monomer that will form the third repeating unit. For example, the monomer that will form the first repeating unit, the monomer that will form the second repeating unit, and, if necessary, the monomer that will form the third repeating unit are dissolved in a solvent, heated under a nitrogen atmosphere, stirred, and then a polymerization initiator is added to obtain the copolymer. The monomer refers to a compound that has a polymerizable functional group and constitutes the minimum repeating unit in the synthesized polymer.

[0068] Examples of the solvent include methanol, ethanol, 2-propanol, TFE (2,2,2-trifluoroethanol), 1,1,1,3,3,3-hexafluoro-2-propanol, THF (tetrahydrofuran), 2-methyltetrahydrofuran, cyclopentyl methyl ether, dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide, toluene, o-xylene, m-xylene, p-xylene, ethyl acetate, propyl acetate, isopropyl acetate, isobutyl acetate, water, and mixed solvents thereof. Examples of polymerization initiators include AIBN (2,2'-azobisisobutyronitrile), V-601 (dimethyl 2,2'-azobis(2-methylpropionate)), VR-110 (2,2'-azobis(2,4,4-trimethylpentane)), VAm-110 (2,2'-azobis(N-butyl-2-methylpropionamide)), V-40 (1,1'-azobis(cyclohexane-1-carbonitrile)), and VE-073 (dimethyl 2,2'-azobis(2-methylpropionate)). 1,1'-azobis (1-cyclohexanecarboxylate)), V-70 (2,2'-Azobis (4-methoxy-2,4-dimethylvaleronitrile)) , V-65 (2,2'-Azobis (2,4-dimethylvaleronitrile)), V-59 (2,2'-Azobis (2-methylbutyronitrile)), and the like.

[0069] <Uses of Nonspecific Reaction Inhibitor> A nonspecific reaction inhibitor containing the copolymer of this embodiment is mixed with a biological sample to suppress nonspecific reactions that occur when measuring a substance to be measured contained in the biological sample. A "biological sample" is also sometimes referred to as a "specimen." Hereinafter, a "biological sample" may be simply referred to as a "sample." By "suppressing nonspecific reactions," measurement errors can be reduced when measuring a substance to be measured contained in the sample, and measurements can be made closer to the true measurement value. Examples of the nonspecific reactions include reactions that reduce or inhibit interactions between desired components, reactions that cause interactions between undesired components, and reactions that promote reactions between components that have such a weak interaction that they are not detectable.

[0070] The biological sample may be derived from a human or an animal. The sample may be blood, culture supernatant, urine, feces, cerebrospinal fluid, saliva, sweat, ascites, or cell or tissue extract. The blood may be whole blood, plasma, serum, or blood that has been subjected to any treatment, such as dilution with an appropriate buffer or purification.

[0071] Examples of the substance to be measured include substances to be measured by biochemical measurement methods described below.

[0072] The non-specific reaction inhibitor of this embodiment can suppress non-specific reactions.

[0073] <Non-specific reaction inhibition method> In the non-specific reaction inhibition method of this embodiment, a non-specific reaction inhibitor is mixed with a biological sample, and when measuring a target substance contained in the biological sample, a non-specific reaction inhibitor is suppressed. As the non-specific reaction inhibitor in the non-specific reaction inhibition method, the non-specific reaction inhibitors described above can be applied, and therefore a redundant description will be omitted.

[0074] By sufficiently dispersing the nonspecific reaction inhibitor in a mixture obtained by mixing the nonspecific reaction inhibitor with a sample, nonspecific reactions can be sufficiently suppressed when measuring the substance to be measured contained in the sample.

[0075] An example of this embodiment is an analytical method in which at least one of a biochemical reaction and a measurement is carried out in the presence of the non-specific reaction inhibitor of the first embodiment.

[0076] In the nonspecific reaction inhibition method of this embodiment, the method for mixing the nonspecific reaction inhibitor with the biological sample is not particularly limited. For example, a method may be used in which the nonspecific reaction inhibitor is added to a buffer solution at a desired concentration to prepare a reagent S, which is then mixed with the sample. The reagent S may be any of a reagent included in a reagent kit for biochemical measurements, a sample diluent, a sample suspension, and a pretreatment solution.

[0077] When Reagent S is a reagent included in a biochemical measurement reagent kit, Reagent S is generally added in a volume 10 to 100 times that of the sample. In this case, the concentration of the antibody or the like, which is the active ingredient of the nonspecific reaction inhibitor in Reagent S, is, for example, preferably 0.1 μg / mL to 5 mg / mL, more preferably 1 μg / mL to 1 mg / mL, even more preferably 5 to 750 μg / mL, and particularly preferably 10 to 500 μg / mL. The concentration of the copolymer, which is the active ingredient of the nonspecific reaction inhibitor in Reagent S, is, for example, preferably 0.001 to 5.00% (w / v), more preferably 0.002 to 2.00% (w / v), even more preferably 0.003 to 1.00% (w / v), and particularly preferably 0.005 to 0.50% (w / v). Within these preferred ranges, the nonspecific reaction can be sufficiently suppressed.

[0078] When Reagent S is a sample dilution solution or a pretreatment solution, Reagent S is generally added in an amount 1 to 10 times the volume of the sample. In this case, the concentration of the antibody or the like, which is the active ingredient of the nonspecific reaction inhibitor in Reagent S, is preferably, for example, 0.1 μg / mL to 5 mg / mL, more preferably 1 μg / mL to 1 mg / mL, even more preferably 5 to 750 μg / mL, and particularly preferably 10 to 500 μg / mL. The concentration of the copolymer, which is the active ingredient of the nonspecific reaction inhibitor in Reagent S, is preferably, for example, 0.001 to 5.00% (w / v), more preferably 0.002 to 4.50% (w / v), even more preferably 0.003 to 3.00% (w / v), and particularly preferably 0.005 to 2.00% (w / v). Within these preferred ranges, the nonspecific reactions can be sufficiently suppressed.

[0079] In order to ensure that the nonspecific reaction inhibitor contacts, binds to, or reacts with components contained in the sample in a mixed solution obtained by mixing the nonspecific reaction inhibitor with the sample, the mixed solution is preferably left for 5 minutes or more, for example, at room temperature or 37° C. By allowing such a mixing time, nonspecific reactions can be sufficiently suppressed when measuring the analyte contained in the sample.

[0080] The concentration of the antibody or fragment thereof, which is the active ingredient of the nonspecific reaction inhibitor, in the mixed solution is, for example, preferably 0.01 μg / mL to 5 mg / mL, more preferably 0.1 μg / mL to 1 mg / mL, even more preferably 0.5 to 750 μg / mL, even more preferably 1 to 500 μg / mL, and particularly preferably 10 to 500 μg / mL. The concentration of the copolymer, which is the active ingredient of the nonspecific reaction inhibitor, in the mixed solution is, for example, preferably 0.0001 to 5.00% (w / v), more preferably 0.0002 to 2.00% (w / v), even more preferably 0.0003 to 1.00% (w / v), even more preferably 0.0005 to 0.5% (w / v), and particularly preferably 0.005 to 0.50% (w / v). Within these preferred ranges, the nonspecific reaction can be sufficiently suppressed.

[0081] Furthermore, at least one of a biochemical reaction and a measurement may be performed in the presence of a nonspecific reaction inhibitor. As an example, a reaction product between a target substance and a substance that specifically binds to the target substance (specific affinity substance) may be measured in a liquid phase containing a biological sample in the presence of a nonspecific reaction inhibitor. To perform this measurement, a solution containing a specific affinity substance may be further added to a mixture obtained by mixing the nonspecific reaction inhibitor with the sample.

[0082] Here, the concentration of the antibody or fragment thereof, which is the active ingredient of the nonspecific reaction inhibitor, in the liquid phase in which the resulting reaction product is measured is, for example, preferably 0.01 μg / mL to 4 mg / mL, more preferably 0.1 μg / mL to 0.8 mg / mL, even more preferably 0.5 to 600 μg / mL, even more preferably 1.0 to 400 μg / mL, and particularly preferably 5 to 400 μg / mL. The concentration of the copolymer, which is the active ingredient of the nonspecific reaction inhibitor, in the liquid phase is, for example, preferably 0.0001 to 4.00% (w / v), more preferably 0.0002 to 1.60% (w / v), even more preferably 0.0003 to 0.80% (w / v), even more preferably 0.0005 to 0.40% (w / v), and particularly preferably 0.003 to 0.40% (w / v). Within these preferred ranges, the nonspecific reaction can be sufficiently suppressed. These preferred concentration ranges are also suitable for other examples and other aspects of this embodiment.

[0083] The method for inhibiting non-specific reactions in this embodiment can be applied to the biochemical measurement method described below.

[0084] <Biochemical Measurement Method> This embodiment includes the following steps (1) to (4): (1) mixing a measurement sample containing a substance to be measured with a non-specific reaction inhibitor containing an antibody or a fragment thereof as an active ingredient, (2) mixing the measurement sample containing the substance to be measured with a non-specific reaction inhibitor containing, as an active ingredient, a copolymer including (i) a first repeating unit having a linear or branched alkyl group with 12 to 40 carbon atoms and (ii) a second repeating unit having a cationic moiety and an anionic moiety, (3) adding a substance with specific affinity for the substance to be measured, and (4) detecting a signal resulting from the reaction of the substance to be measured with the specific affinity substance.

[0085] The non-specific reaction inhibitor in the biochemical measurement method can be the non-specific reaction inhibitor of the first embodiment described above, and therefore a duplicated description will be omitted. However, the non-specific reaction inhibitor used in step (1) above may or may not contain a copolymer containing the first repeating unit and the second repeating unit described in the first embodiment. The non-specific reaction inhibitor used in step (2) above may or may not contain the antibody or a fragment thereof described in the first embodiment.

[0086] Steps (1) and (2) may be performed simultaneously, or either step (1) or step (2) may be performed first. It is preferable to perform steps (1) and (2) first, followed by steps (3) and (4) in this order.

[0087] In biochemical measurements, a substance with specific affinity for the substance to be measured is used. If the substance to be measured is an antibody, the specific affinity substance can be the corresponding antigen. If the substance to be measured is an antigen, the specific affinity substance can be the corresponding antibody. Furthermore, if the substance to be measured is labeled with avidin or biotin, the specific affinity substance can be biotin or avidin. Of these, measurements that utilize antigen-antibody reactions are called immunological measurements.

[0088] The type of immunological measurement is not particularly limited, and various known methods can be applied, such as turbidimetric immunoassay (TIA), latex turbidimetric immunoassay (LTIA), immunochromatography (lateral flow type, flow-through type), electrochemiluminescence assay (ECLIA), chemiluminescence assay (CLIA), chemiluminescent enzyme immunoassay (CLEIA), and enzyme-linked immunosorbent assay (ELISA).

[0089] When the biochemical measurement method is LTIA, the non-specific reaction inhibition method may include contacting a biological sample with insoluble carrier particles carrying a substance with specific affinity for the substance to be measured in a liquid phase in the presence of a non-specific reaction inhibitor, and measuring a signal generated by an agglutination reaction between the substance to be measured and the insoluble carrier particles.

[0090] Generally, biochemical measurements are broadly divided into homogeneous and heterogeneous methods. The homogeneous method is a method that does not involve a washing process (so-called binding (B) / non-binding (F) separation process) for separating reaction products generated in a mixed solution of a biological sample and a reagent solution involving the substance to be measured from other substances (such as contaminants) contained in the biological sample. The reagent of this embodiment (a biochemical measurement reagent described below) can suppress nonspecific reactions in the sample and improve the detection accuracy of antigen-antibody reactions. For this reason, the reagent of this embodiment is preferably used in the homogeneous method. In particular, it is widely used in biochemical measurements. Furthermore, it is more preferably used in LTIA.

[0091] LTIA is described in detail below as an example of a biochemical measurement method. LTIA is a method for measuring a target substance using latex particles to which a substance with specific affinity for the target substance, such as an antigen or antibody, is immobilized, and is widely used in the field of clinical testing.

[0092] Methods for measuring antigens, which are analytes, using LTIA can be broadly divided into two types: (a) a method in which latex particles onto which antibodies against the analyte are immobilized react with the analyte antigen to form a sandwich-type immune complex, and the analyte (antigen) is measured based on the degree of agglutination of the latex particles associated with immune complex formation; and (b) a method in which the antigen-immobilized latex particles and the antigen (analyte) in a sample compete with free antibodies added to a separate reagent to inhibit the formation of an immune complex between the latex particles and the antibody, and the analyte (antigen) is measured based on the degree of inhibition of agglutination of the latex particles associated with the inhibition of immune complex formation. This method can also use a combination of free antibodies added to the reagent and latex particles onto which antibodies against the analyte are immobilized. Both the antibody and the antigen can be immobilized to latex particles.

[0093] In LTIA, some components contained in the sample may cause agglutination that should not occur (positive measurement error) or agglutination that should occur may not occur (negative measurement error) in latex particles that have immobilized a substance with specific affinity for the substance to be measured. These are called non-specific reactions, and they impair the accuracy and reliability of the measurement.

[0094] By suppressing non-specific reactions, the measurement error can be reduced, and the positive or negative measurement error of the above-mentioned measurement value can be brought closer to the original measurement value (true value). Although the cause of non-specific reactions is not necessarily clear, there are cases in which immunoglobulins such as HAMA and rheumatoid factor, chyle, simple lipids, neutral lipids, and the like are thought to be involved.

[0095] In LTIA, the test substance can be measured by optically or electrochemically observing the degree of agglutination. Optical observation methods include methods (endpoint method, rate method, etc.) that measure scattered light intensity, absorbance, or transmitted light intensity using optical equipment. The measured values, such as absorbance, obtained by measuring a sample are compared with the measured values, such as absorbance, obtained by measuring a standard substance (a sample with a known concentration of the substance to be measured), to calculate the concentration (quantitative value) of the substance to be measured contained in the sample. Measurement of absorbance, such as transmitted light or scattered light, may be performed using either a single wavelength or a dual wavelength (the difference or ratio between two wavelengths). Measurement wavelengths are generally selected from 500 to 900 nm.

[0096] The LTIA may be performed using a measuring device. The measuring device may be a general-purpose analyzer or a dedicated automatic measuring device. The LTIA is generally performed in multiple steps, such as a two-step method (two-reagent method).

[0097] The substance to be measured in the non-specific reaction inhibition method of this embodiment is not particularly limited as long as it is a substance that can be measured by a known immunological measurement method, and examples thereof include proteins (antigens, haptens, antibodies, etc.), carbohydrates, lipids, glycoproteins, glycolipids, nucleic acids, chemical substances (hormones, drugs), etc. Among these, antigens or antibodies are preferred, and antigens consisting of proteins are more preferred. Specific examples include soluble interleukin-2 receptor (sIL-2R), CRP, fibrin and fibrinogen degradation products, D-dimer, soluble fibrin (SF), lipoprotein(a) (Lp(a)), matrix metalloproteinase-3 (MMP-3), prostate-specific antigen (PSA), IgG, IgA, IgM, IgE, IgD, antistreptolysin O antibody, rheumatoid factor, transferrin, haptoglobin, α1-antitrypsin, α1-acidoglycoprotein, α2-macroglobulin, hemopexin, Antithrombin-III, α-fetoprotein, carcinoembryonic antigen (CEA), ferritin, HBs-Ag (hepatitis B envelope antigen), anti-HBs (anti-hepatitis B envelope antibody), HBe-Ag (hepatitis B e antigen), anti-HBe (anti-hepatitis B e antibody), anti-HBc (anti-hepatitis B core antibody), SARS-Cov-2, human brain natriuretic peptide (BNP), pulmonary surfactant protein D (SP-D), thymus and activation-regulated chemokine (TARC, CCL-17), and procalcitonin.

[0098] Substances that have a specific affinity for the substance to be measured and are carried on insoluble carrier particles such as latex include proteins, peptides, amino acids, lipids, carbohydrates, glycoproteins, glycolipids, nucleic acids, and haptens that are used in known biochemical measurement methods. Generally, antibodies or antigens are often used.

[0099] The antibody may be a polyclonal antibody or a monoclonal antibody. The antibody may be a whole antibody molecule or a functional fragment having antigen-antibody activity. The antibody may be obtained by immunizing an animal such as a mouse, or may be synthesized by protein engineering. Examples of such antibodies include antibodies treated with protease, F(ab')2, Fab', single-chain antibodies (scFv), chimeric antibodies, humanized antibodies, and bispecific antibodies (BsAb). The antibody may be obtained by known methods.

[0100] The latex particles used in LTIA are not particularly limited, and any latex particles commonly used as reagents for biochemical measurements can be used. The latex particles are formed, for example, by polymerizing one or more of the following monomers: Specific examples of the monomer include polymerizable monomers having a phenyl group such as styrene, α-methylstyrene, o-methylstyrene, p-methylstyrene, p-chlorostyrene, 4-vinylbenzoic acid, divinylbenzene, and vinyltoluene; polymerizable monomers having a phenyl group and a sulfonate such as styrene sulfonate, divinylbenzene sulfonate, o-methylstyrene sulfonate, and p-methylstyrene sulfonate; polymerizable unsaturated aromatics such as polymerizable monomers having a naphthyl group such as 1-vinylnaphthalene, 2-vinylnaphthalene, α-naphthyl (meth)acrylate, and β-naphthyl (meth)acrylate; polymerizable unsaturated carboxylic acids such as (meth)acrylic acid, itaconic acid, maleic acid, and fumaric acid; methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, and (meth)acrylic acid; polymerizable unsaturated carboxylic acid esters such as 2-hydroxyethyl (meth)acrylate, glycidyl (meth)acrylate, ethylene glycol-di-(meth)acrylate, and tribromophenyl (meth)acrylate; polymerizable unsaturated nitriles such as (meth)acrylonitrile; polymerizable unsaturated aldehydes such as (meth)acrolein; polymerizable unsaturated ketones such as 3-methyl-3-buten-2-one; polymerizable unsaturated carboxylic acid amides such as (meth)acrylamide, N-methylol-(meth)acrylamide, and methylenebis(meth)acrylamide; conjugated dienes such as butadiene and isoprene; vinyl esters such as vinyl acetate; polymerizable unsaturated heterocyclic rings such as vinylpyridine; vinyl amides such as N-vinylpyrrolidone; and vinyl halides such as vinyl chloride, vinylidene chloride, and vinyl bromide.

[0101] The average particle size of the latex particles used in LTIA can be selected from, for example, 0.02 to 1.6 μm, preferably 0.1 to 0.4 μm, taking into consideration the concentration of the substance to be measured in the sample or the detection sensitivity of the measuring instrument, etc. Here, the average particle size can be measured using a particle size distribution analyzer.

[0102] The method for loading one or more of the specific affinity substances onto latex particles used in LTIA is not particularly limited, and loading may be performed by known methods such as physical adsorption (hydrophobic bonding), chemical bonding, etc. For the purpose of preventing nonspecific adsorption of contaminant substances to latex particles loaded with a specific affinity substance, the latex particles may be subjected to a known blocking treatment (masking treatment) in which the latex particles are brought into contact with a protein such as bovine serum albumin (BSA), casein, gelatin, egg albumin or a salt thereof, a polymer compound such as a polysaccharide, a surfactant, or skim milk powder.

[0103] <Reagent for Biochemical Measurements> The reagent for biochemical measurements in this embodiment contains (a) an antibody or a fragment thereof, and (b) a copolymer containing (1) a first repeating unit having a linear or branched alkyl group having 12 to 40 carbon atoms, and (2) a second repeating unit having both a cationic moiety and an anionic moiety. (a) and (b) can be included as non-specific reaction inhibitors. The non-specific reaction inhibitor in the reagent for biochemical measurements can be the same as the non-specific reaction inhibitor of the first embodiment described above, and therefore a redundant description will be omitted.

[0104] The biochemical measurement reagent is a reagent used to measure a biochemical reaction that occurs in a biological sample and detects the binding between a biochemical substance to be measured and a substance that has specific affinity for the substance to be measured. The biochemical measurement reagent includes the non-specific reaction inhibitor of the first embodiment described above. The non-specific reaction inhibitor is included as an active ingredient that inhibits non-specific reactions in the biological sample. As the non-specific reaction inhibitor described above can be applied, a redundant description will be omitted. Furthermore, as the biochemical reaction is also as described above, a redundant description will be omitted.

[0105] A typical example of the binding occurring in the sample is an antigen-antibody reaction. In the antigen-antibody reaction, the substance to be measured may be an antigen or an antibody. Examples of binding other than the antigen-antibody reaction include binding between avidin and biotin, binding between protein A and the Fc region of immunoglobulin, binding between protein G and the Fc region of immunoglobulin, and binding between protein L and the κ chain of immunoglobulin.

[0106] (Configuration of the Reagent for Biochemical Measurement) The configuration of the reagent for biochemical measurement of this embodiment may be any configuration containing the nonspecific reaction inhibitor of the first embodiment, for example, a two-reagent configuration in which the first reagent contains the nonspecific reaction inhibitor and the second reagent contains latex particles. Furthermore, the reagent may be a multi-reagent configuration containing a third or subsequent nth reagent (n represents an integer of 3 or greater) containing other components. The nonspecific reaction inhibitor may be contained in a second reagent other than the first reagent or in the nth reagent together with other components. The antibody and the copolymer may be contained in different reagents. The nonspecific reaction inhibitor is preferably contained in the first reagent.

[0107] The biochemical assay reagent of this embodiment may contain other components to the extent that the nonspecific reaction inhibitory effect is not impaired. Examples of other components include buffers, proteins, peptides, amino acids, nucleic acids, lipids, phospholipids, sugars, inorganic salts, polymeric compounds, surfactants, other nonspecific reaction inhibitors, and preservatives. Components that buffer or adjust the pH, ionic strength, osmotic pressure, etc. of the sample may include buffers such as acetic acid, citric acid, phosphoric acid, Tris, glycine, boric acid, carbonate, phthalic acid, succinic acid, maleic acid, and imidazole, as well as Good's buffers and their sodium, potassium, and calcium salts. Polymers such as polyvinylpyrrolidone and phospholipid polymers may also be included as components that enhance agglutination formation.

[0108] A specific example of the reagent configuration is a two-reagent type biochemical measurement reagent, in which the first reagent is a solution in which a non-specific reaction inhibitor has been added to a buffer solution for diluting the sample, and the second reagent is a solution in which latex particles carrying a specific affinity substance are dispersed in a buffer solution or the like.

[0109] Furthermore, when a diluent, a pretreatment liquid, or the like is added to a sample before subjecting the sample to biochemical measurement, the nonspecific reaction inhibitor of the first embodiment may be contained in the diluent or pretreatment liquid. Furthermore, one type of nonspecific reaction inhibitor of the first embodiment may be contained in the diluent or pretreatment liquid, and one type may be contained in the nth reagent. For example, a nonspecific reaction inhibitor having an antibody or the like as an active ingredient may be contained in the diluent, and a nonspecific reaction inhibitor having a copolymer as an active ingredient may be contained in the first reagent. Furthermore, a nonspecific reaction inhibitor having an antibody or the like as an active ingredient may be contained in the first reagent, and a nonspecific reaction inhibitor having a copolymer as an active ingredient may be contained in the pretreatment liquid.

[0110] <Concentration of Non-Specific Reaction Inhibitor> In the reagent for biochemical measurements of this embodiment, when the first reagent contains a non-specific reaction inhibitor, the concentration of the antibody or fragment thereof, which is the active ingredient of the non-specific reaction inhibitor in the first reagent, is preferably, for example, 0.1 μg / mL to 5 mg / mL, more preferably 1 μg / mL to 1 mg / mL, even more preferably 5 to 750 μg / mL, and particularly preferably 10 to 500 μg / mL. The concentration of the copolymer, which is the active ingredient of the non-specific reaction inhibitor in the first reagent, is preferably, for example, 0.001 to 5.00% (w / v), more preferably 0.002 to 2.00% (w / v), even more preferably 0.003 to 1.00% (w / v), and particularly preferably 0.005 to 0.50% (w / v). Within these preferred ranges, the non-specific reaction inhibitory effect is high.

[0111] <Method of Using the Reagent for Biochemical Measurement> Examples of methods of using the reagent for biochemical measurement of this embodiment include the following methods (1) to (4), in which a biological sample containing a substance to be measured is brought into contact with latex particles carrying a substance with specific affinity for the substance to be measured in the presence of a non-specific reaction inhibitor. (1) A method of mixing a biological sample with a first reagent containing a non-specific reaction inhibitor and a buffer solution of an optional component, etc., and then mixing this mixture with a second reagent containing latex particles carrying a substance with specific affinity for the substance to be measured and a buffer solution of an optional component, etc. (2) A method of simultaneously mixing a biological sample with a first reagent containing a non-specific reaction inhibitor and a buffer solution of an optional component, etc., and a second reagent containing latex particles carrying a substance with specific affinity for the substance to be measured and a buffer solution of an optional component, etc. (3) A method of mixing a biological sample with a second reagent containing latex particles carrying a substance with specific affinity for the substance to be measured and a buffer solution of an optional component, etc., and then adding the first reagent containing a non-specific reaction inhibitor and a buffer solution of an optional component, etc., to this mixture and mixing them together (4) A method of mixing a first reagent containing a non-specific reaction inhibitor and a buffer solution of an optional component, etc., with a second reagent containing latex particles carrying a substance with specific affinity for the substance to be measured and a buffer solution of an optional component, etc., and then adding the biological sample to this mixture and mixing them together

[0112] Among the above methods, from the viewpoint of suppressing non-specific reactions, method (1), (2) or (4) is preferred, (1) or (4) is more preferred, and method (1) is particularly preferred.

[0113] <Biochemical Measurement Reagent Kit> The biochemical measurement reagent kit of this embodiment is a reagent kit including the above-described biochemical measurement reagent. The biochemical measurement reagent in the biochemical measurement reagent kit of this embodiment has been described above, so duplicated description will be omitted.

[0114] Components other than the biochemical measurement reagent that may be included in the biochemical measurement reagent kit of this embodiment include, for example, instructions for use of the reagent, blood sample collection tools (collection pipettes, syringes, cotton swabs, filtration filters, etc.), a detection device, an analysis device, etc.

[0115] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the examples described below.

[0116] The materials used in this example are listed below. Stearyl methacrylate (CAS number [32360-05-7]), manufactured by Tokyo Chemical Industry Co., Ltd. 4-[3-methacrylamidopropyl]dimethylammonio]butane-1-sulfonic acid (CAS number [83623-32-9]), manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. Methyl methacrylate (CAS number [80-62-6]), manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. AIBN (2,2'-Azobis(isobutylonitrile)), manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. Acetone, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. TFE (2,2,2-Trifluoroethanol), manufactured by Tokyo Chemical Industry Co., Ltd. THF (tetrahydrofuran), manufactured by Tokyo Chemical Industry Co., Ltd. Ethanol, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. 2-Methacryloyloxyethyl-2'-(trimethylammonio)ethyl phosphate (CAS number [67881-98-5]), manufactured by Tokyo Chemical Industry Co., Ltd. Otsuka Saline Injection (0.9 w / v% sodium chloride aqueous solution), manufactured by Otsuka Pharmaceutical Factory, Ltd.

[0117] Experimental Example 1: Synthesis of Copolymer 1. Betaine-Type Copolymer 0.104 g (0.306 mmol) of stearyl methacrylate, 1.50 g (4.90 mmol) of 4-[3-methacrylamidopropyl]dimethylammonio]butane-1-sulfonic acid, and 97.8 μL (0.918 mmol) of methyl methacrylate were dissolved in a mixture of 6.36 mL of TFE and 1.59 mL of THF. After stirring at 60°C for 30 minutes under a nitrogen atmosphere, 0.119 g (0.726 mmol) of AIBN was added. After further stirring at 60°C for 20 hours, the mixture was cooled to room temperature, and the reaction solution was added to 99.0 mL of acetone, and the solid was collected by filtration. 10.0 mL of acetone was added to the obtained solid, and the mixture was stirred. The solid was then collected by filtration. This acetone washing and filtration were repeated two more times, and the obtained solid was dried under reduced pressure to obtain 1.61 g of copolymer. The copolymer was dissolved in a 0.9 w / v % aqueous sodium chloride solution and then filtered through a membrane filter (material: polyvinylidene fluoride (PVDF), pore size: 0.45 μm) to obtain a copolymer solution.

[0118] 2. Phosphorylcholine-type copolymer: 0.323 g (0.953 mmol) of stearyl methacrylate, 1.50 g (5.08 mmol) of 2-methacryloyloxyethyl-2'-(trimethylammonio)ethyl phosphate, and 33.8 μL (0.318 mmol) of methyl methacrylate were dissolved in 8.25 mL of ethanol. After stirring at 60°C for 30 minutes under a nitrogen atmosphere, 0.124 g (0.753 mmol) of AIBN was added. After stirring at 60°C for an additional 20 hours, the mixture was cooled to room temperature. 5 mL of the reaction solution was weighed out, 5 mL of water was added, and the mixture was placed in a dialysis tube (manufactured by Sekisui Material Solutions Co., Ltd., main component: regenerated cellulose, pore size: 50 Å, permeable molecular weight: 14,000). The mixture was dialyzed once against a mixture of 100 mL of ethanol and 100 mL of water, and five times against 200 mL of water. The solids concentration of the resulting dialysate was measured, and water was added to adjust the solids concentration to 5 wt %. The resulting solution was filtered through a membrane filter (material: PVDF, pore size: 0.45 μm) to obtain a copolymer solution.

[0119] 3. Measurement of Molecular Weight The weight average molecular weight of the copolymer was measured by the following method.

[0120] <Measurement apparatus> Apparatus: GPC-101 (manufactured by Shodex) Detector: RI (RI-71S manufactured by Shodex) Sample column: OHpak SB-804 HQ (manufactured by Shodex) Reference column: OHpak SB-802.5 HQ (manufactured by Shodex) Guard column: OHpak SB-G 6B (manufactured by Shodex)

[0121] <Measurement conditions> Eluent: 0.1 M Tris buffer (pH = 9) with 0.1 M potassium chloride added / methanol = 8 / 2 (volume ratio) Flow rate: 0.8 mL / min Injection volume: 100 μL Column temperature: 40°C Standard sample: PEG / PEO calibration kit (EasiVial PEG / PEO (GL Sciences), PL2080-0201 (Agilent))

[0122] <Measurement results> Betaine type copolymer: weight average molecular weight (Mw) = 23,000 Phosphorylcholine type copolymer: weight average molecular weight (Mw) = 42,000

[0123] [Experimental Example 2] Verification of Non-Specific Reaction Inhibitory Effect - 1 1. Measurement Reagents A first reagent base solution was prepared with the following composition: 100 mM Bis-Tris-HCl (pH 6.5) 600 mM NaCl 0.2% BSA A non-specific reaction inhibitor shown in Table 1 was added to the first reagent base solution to the final concentration shown in Table 1 to prepare a first reagent. However, in Comparative Example 1, the first reagent base solution was used as is without adding the non-specific reaction inhibitor. The mouse anti-human IgM antibody used in Comparative Example 2 and Examples 1 and 2 was obtained by the method described in Japanese Patent No. 4625879. Mice were used for immunization. This antibody was a monoclonal antibody. The mouse anti-human IgL chain κ antibody used in Comparative Example 5 and Examples 3 and 4 was the S06205 antibody obtained by the method described in International Publication WO 2024 / 048583. Mice were used for immunization. This antibody was a monoclonal antibody.

[0124]

[0125] 5 mM MOPS-NaOH (pH 7.0) Anti-human procalcitonin monoclonal antibody-sensitized latex (one type) Procalcitonin; Recombinant human procalcitonin: Hytest Inc. The anti-human procalcitonin monoclonal antibody was obtained using a commercially available procalcitonin antigen by a method known to those skilled in the art. The anti-human procalcitonin monoclonal antibody-sensitized latex was prepared with reference to the method described in JP 2017-181377 A. That is, an anti-human procalcitonin monoclonal antibody solution diluted to 0.36 mg / mL with an equivalent amount of 5 mM Tris-HCl (pH 8.5) was added to a 1.0% latex solution (5 mM Tris buffer solution (hereinafter referred to as Tris-HCl or simply Tris) (pH 8.5)) having an average particle size of 0.3 μm, and the mixture was stirred at 4° C. for 2 hours. Thereafter, an equal amount of 5 mM Tris-HCl (pH 8.5) containing 0.5% BSA was added, and the mixture was stirred at 4° C. for 1 hour to prepare an anti-human procalcitonin monoclonal antibody-sensitized latex particle solution. The latex particle solution was diluted with 5 mM MOPS-NaOH (pH 7.0) so that the absorbance at 600 nm became approximately 4.0 OD, and this was used as the second reagent.

[0126] 2. Sample 2-1 Chyle Sample Randomly extracted human serum was mixed to obtain pooled serum. This pooled serum was mixed with chyle from Interference Check A Plus (Sysmex Corporation) according to the method described in the manufacturer's instructions. A blank sample and chyle sample (1500 FTU (formazin turbidity)) were prepared.

[0127] 2-2 Serum samples Eight human serum samples were used, each from a different donor.

[0128] 3. Measurement Method: The first and second reagents were combined and the sample was measured using a Hitachi 7180 automatic analyzer. Specifically, 120 μL of the first reagent was added to 15.0 μL of sample, and the mixture was incubated at 37°C for 5 minutes. Then, 40 μL of the second reagent was added and stirred. The absorbance was measured over the next 5 minutes at a dominant wavelength of 570 nm and a secondary wavelength of 800 nm. The difference between the absorbance measured 5 minutes after the addition of the second reagent and the absorbance measured immediately after the addition of the second reagent was evaluated as the change in absorbance (mAbs).

[0129] 4. Measurement Results For the chyle samples, the absorbance change of the chyle sample minus the absorbance change of the blank sample (mAb) was calculated and is shown in Table 2. For the serum samples (Sample 1 to Sample 8), the absorbance change (mAb) is shown in Table 2. The degree of absorbance change for each sample in Comparative Examples 1 to 4 and Example 1 was evaluated and summarized in Table 3. ・"None" indicates an absorbance change of less than 4.0 mAb ・"Minor" indicates an absorbance change of 4.0 mAb or more but less than 10.0 mAb ・"Severe" indicates an absorbance change of 10.0 mAb or more The number of samples that fell into each category is shown.

[0130]

[0131]

[0132] 5. Discussion The antigen procalcitonin is not a polyvalent antigen, meaning it has multiple identical epitopes within the molecule. Therefore, in Experimental Example 2, in which only one type of antibody-sensitized latex was used as the second reagent, no agglutinates were formed even when the procalcitonin in the sample reacted with the antibody-sensitized latex, and the absorbance remained unchanged. In contrast, an increase in absorbance is interpreted as a nonspecific reaction, in which some component present in the sample nonspecifically agglutinated the antibody-sensitized latex.

[0133] The amount of change in absorbance for each sample is discussed below.

[0134] Samples 1 and 2 were samples in Comparative Example 1, in which no nonspecific reaction inhibitor was added, in which the absolute value of the absorbance change was 3.3 mAbs or less, and no nonspecific reaction occurred. For both samples, in Comparative Examples 2 to 4 and Example 1, the absolute value of the agglutination amount was 2.8 mAbs or less, and no nonspecific reaction occurred. The amount of absorbance change in the samples did not change even when anti-human IgM antibody, betaine-type copolymer, phosphorylcholine-type copolymer, or both anti-human IgM antibody and betaine-type copolymer were added as nonspecific reaction inhibitors.

[0135] ​Sample 3 was determined to exhibit no nonspecific reactions in Comparative Example 1. However, in Comparative Example 2, in which an anti-human IgM antibody was added, the absorbance change was 8.4 mAbs, indicating a nonspecific reaction. Anti-human IgM antibodies are a component widely used as a nonspecific reaction inhibitor, as described in Patent Document 1. In fact, nonspecific reactions are reduced or suppressed in Samples 4 to 6. However, as in Sample 3, nonspecific reactions can also occur. This phenomenon is a major obstacle to developing highly accurate biochemical assay reagents for measuring biological samples collected from an unspecified number of donors. In contrast, in Example 1, in which both an anti-human IgM antibody and a betaine-type copolymer were added, the absorbance change was reduced to 2.2 mAbs, indicating no nonspecific reaction. The copolymer eliminated nonspecific reactions caused by anti-human IgM antibodies.

[0136] Samples 4 to 8 were samples in which non-specific reactions occurred in Comparative Example 1.

[0137] For sample 4, when anti-human IgM antibody or copolymer was added alone, as in Comparative Examples 2 to 4, the non-specific reaction was reduced but not completely suppressed. When anti-human IgM antibody or copolymer was added alone, the amount of change in absorbance was roughly the same. However, as shown in Examples 1 and 2, by using anti-human IgM antibody and copolymer in combination, the amount of change in absorbance was significantly reduced to 1.8 mAbs. compared to when the antibody or copolymer was used alone, and the non-specific reaction was successfully eliminated.

[0138] When anti-human IgL chain (κ) antibody was added alone to sample 4, the nonspecific reaction was slightly reduced (Comparative Example 5). However, as shown in Examples 3 and 4, when anti-human IgL chain (κ) antibody and the copolymer were used in combination, the amount of change in absorbance was smaller than when either antibody was added alone, and the nonspecific reaction was further reduced.

[0139] In samples 5 and 6, the anti-human IgM antibody was able to suppress nonspecific reactions, but the copolymer was only able to slightly reduce the nonspecific reactions. As in Example 1, when the antibody and the copolymer were used in combination, the antibody's effect of suppressing nonspecific reactions was maintained, and nonspecific aggregation did not occur. The copolymer did not inhibit the nonspecific reaction suppression effect of the anti-human IgM antibody.

[0140] In samples 7 and 8 and the chyle sample, the copolymer was able to suppress or significantly reduce nonspecific reactions, but the antibody was unable to reduce nonspecific reactions at all. As in Example 1, when the antibody and the copolymer were used in combination, the nonspecific reaction suppression effect of the copolymer was maintained. For samples 7 and 8, the absorbance change in Example 1 was comparable to that in Comparative Examples 3 and 4. For the chyle sample, the absorbance change in Example 1 was smaller than that in Comparative Example 3. The antibody did not inhibit the nonspecific reaction suppression effect of the copolymer.

[0141] The degree of change in absorbance of the specimens in the measurements of Comparative Examples 1 to 4 and Example 1 is shown in Table 3. Only Example 1 had no "serious" results. Example 1 was able to suppress non-specific reactions in a wide variety of samples.

[0142] Previously, it was considered to combine antibodies effective in suppressing nonspecific reactions with antibodies against different antigens, such as anti-human IgM antibodies and anti-human IgL chain (κ) antibodies. However, as shown in Sample 3 of Comparative Example 2, the antibodies added to suppress nonspecific reactions could cause new nonspecific reactions, limiting the improvement of measurement accuracy. The copolymers investigated here are all copolymers that the inventors have found to be effective in suppressing nonspecific reactions. The fact that these copolymers have the effect of suppressing nonspecific reactions caused by nonspecific reaction inhibitors whose main component is an antibody was a new property that even the inventors could not have predicted. This new property will greatly contribute to the construction of more accurate biochemical measurement reagents.

[0143] [Experimental Example 3] Verification of the effect of suppressing non-specific reactions - 2 Using the LTIA reagent, the correlation with an already approved reagent (heterogeneous method) was evaluated.

[0144] 1. Measurement by CLEIA method The CLEIA method involves a B / F separation procedure and a washing step. Therefore, it is a measurement method that is less susceptible to the influence of non-specific reactions derived from the sample. The measurement value by this method was used as the control value of the sIL-2R concentration in each specimen.

[0145] 1-1. Measurement reagent (approved reagent) Determiner CL (registered trademark) IL-2R NX (Minaris Medical Co., Ltd.) was used.

[0146] 1-2. Samples: 9 human serum samples (however, each sample comes from a different donor).

[0147] 1-3. Measurement Method Measurement was performed using CL-JACK NX (registered trademark) (Minaris Medical Co., Ltd.) according to the instructions attached to the measurement reagent.

[0148] 2. Measurement by LTIA Method (Comparative Example 6, Example 5) 2-1 Measurement Reagents A first reagent and a second reagent were prepared according to the methods described in JP 2017-181377 A and JP 2018-173429 A. In Comparative Example 6, a mouse anti-human IgM antibody was added to the first reagent to a final concentration of 100 μg / mL. In Example 5, a reagent was used in which a mouse anti-human IgM antibody was added to the first reagent to a final concentration of 100 μg / mL and the betaine copolymer synthesized in Experimental Example 1 was added to a final concentration of 0.10 wt %.

[0149] 2-2 Sample: Same as sample 1-2.

[0150] 2-3 Measurement Method: The first and second reagents were combined and the sIL-2R concentration in the sample was measured using a Hitachi 7180 automated analyzer. Specifically, 120 μL of the first reagent was added to 5.6 μL of sample and incubated at 37°C for 5 minutes. Then, 40 μL of the second reagent was added and stirred. The absorbance change associated with aggregate formation was measured over the next 5 minutes at a dominant wavelength of 570 nm and a subwavelength of 800 nm. The absorbance change was applied to a calibration curve obtained by measuring a standard substance of known concentration, and the measured value was calculated. Next, a scatter plot was created with the sIL-2R measured value of the approved reagent on the horizontal axis and the measured value of Comparative Example 6 on the vertical axis, as shown in Figure 1. Furthermore, the slope and correlation coefficient were calculated using statistical methods. Similarly, for Example 5, a scatter plot is shown in Figure 2, and the correlation coefficient was calculated. Similarly, scatter plots were prepared for six human serum samples whose values ​​measured with approved reagents were less than 1000 U / mL, and are shown in Figure 3 for Comparative Example 6 and Figure 4 for Example 5. Furthermore, correlation coefficients were calculated using statistical methods.

[0151] 3. Results In Comparative Example 6, in which only an antibody was used as the nonspecific reaction inhibitor, the correlation coefficient r was 0.992. In contrast, in Example 5, in which an antibody and a copolymer were used in combination, the correlation coefficient r improved to 0.997. The correlation coefficient r in Comparative Example 6 when analyzing human serum samples (6 samples) whose measured values ​​measured with an approved reagent were less than 1000 U / mL was 0.944. In contrast, in Example 5, the correlation coefficient r improved to 0.997. When a nonspecific reaction inhibitor containing an antibody or a fragment thereof and a copolymer with a molecular weight of 1000 or more as active ingredients was added to a biochemical measurement reagent, the measurement accuracy was improved compared to when a nonspecific reaction inhibitor containing only an antibody or a fragment thereof as an active ingredient was added.

Claims

1. A non-specific reaction inhibitor for use in biochemical measurements, comprising, as active ingredients, (a) an antibody or a fragment thereof, and (b) a copolymer comprising (1) a first repeating unit having a linear or branched alkyl group having 12 to 40 carbon atoms, and (2) a second repeating unit having a cationic moiety and an anionic moiety.

2. The non-specific reaction inhibitor according to claim 1, wherein the first repeating unit has a structure represented by formula (1). (In formula (1), R １ is a hydrogen atom or a methyl group, X is an NH or an oxygen atom, and A is a linear or branched alkyl group having 12 to 40 carbon atoms.

3. The non-specific reaction inhibitor according to claim 1, wherein the cationic moiety of the second repeating unit is a quaternary ammonium group.

4. A non-specific reaction inhibitor according to claim 1 or 2, wherein the second repeating unit has a structure represented by formula (2) and / or formula (3). (In formula (2), R ２ is a hydrogen atom or a methyl group, and R ３ and R ４ are each independently a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and Y １ is an NH or oxygen atom, and Z is SO ３ － or COO － wherein n and m are each independently an integer of 1 to 5. (In formula (3), R ５ is a hydrogen atom or a methyl group, and R ６ , R ７ , R ８ are each independently a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and Y ２ is NH or an oxygen atom, and k and l each independently represent an integer of 1 to 5.

5. The non-specific reaction inhibitor according to claim 2, wherein A in the formula (1) is a linear or branched alkyl group having 12 to 28 carbon atoms.

6. The second repeating unit contains a structure represented by formula (2), and R in formula (2) ３ and R ４ The non-specific reaction inhibitor according to claim 4, wherein is a methyl group.

7. The second repeating unit contains a structure represented by formula (3), and R in formula (3) ６ , R ７ and R ８ The non-specific reaction inhibitor according to claim 4, wherein is a methyl group, and k and l are each 2.

8. The non-specific reaction inhibitor according to claim 1, wherein the copolymer further comprises a third repeating unit having a molecular weight of 1,000 or less.

9. The non-specific reaction inhibitor according to claim 8, wherein the third repeating unit is a repeating unit formed by any one monomer selected from the group consisting of (meth)acrylic acid, methyl (meth)acrylate, 2-methoxyethyl acrylate, and vinylpyrrolidone.

10. The non-specific reaction inhibitor according to claim 1, wherein the antibody or fragment thereof is at least one selected from the group consisting of an antibody against an immunoglobulin or a fragment thereof, an anti-M protein antibody, an anti-cryoglobulin antibody, an anti-pyroglobulin antibody, an anti-rheumatoid factor antibody, an anti-complement antibody and a decoy antibody.

11. The non-specific reaction inhibitor according to claim 10, wherein the immunoglobulin or a fragment thereof is an immunoglobulin or a fragment thereof derived from any one animal selected from the group consisting of human, mouse, rat, rabbit, cow, goat, sheep, alpaca, dog, cat and bird.

12. The non-specific reaction inhibitor according to claim 1, wherein the antibody or fragment thereof is derived from any one animal selected from the group consisting of mouse, rat, rabbit, cow, goat, and alpaca.

13. The non-specific reaction inhibitor according to claim 1, wherein the antibody or fragment thereof is an antibody or fragment thereof derived from a mouse.

14. The non-specific reaction inhibitor according to claim 1, wherein the antibody or fragment thereof is an antibody or fragment thereof modified with a polymer compound.

15. A method for inhibiting non-specific reactions, comprising mixing the non-specific reaction inhibitor according to claim 1 or 2 with a biological sample, and inhibiting non-specific reactions of the object to be measured when measuring the object to be measured contained in the biological sample.

16. A reagent for biochemical measurement, comprising: (a) an antibody or a fragment thereof; and (b) a copolymer comprising: (1) a first repeating unit having a linear or branched alkyl group having 12 to 40 carbon atoms; and (2) a second repeating unit having a cationic moiety and an anionic moiety.

17. The reagent for biochemical measurements according to claim 16, wherein the first repeating unit has a structure represented by formula (1). (In formula (1), R １ is a hydrogen atom or a methyl group, X is an NH or an oxygen atom, and A is a linear or branched alkyl group having 12 to 40 carbon atoms.

18. The reagent for biochemical measurements according to claim 16, wherein the cationic moiety of the second repeating unit is a quaternary ammonium group.

19. The reagent for biochemical measurements according to claim 16 or 17, wherein the second repeating unit has a structure represented by formula (2) and / or formula (3). (In formula (2), R ２ is a hydrogen atom or a methyl group, and R ３ and R ４ are each independently a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and Y １ is an NH or oxygen atom, and Z is SO ３ － or COO － wherein n and m are each independently an integer of 1 to 5. (In formula (3), R ５ is a hydrogen atom or a methyl group, and R ６ , R ７ , R ８ are each independently a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and Y ２ is NH or an oxygen atom, and k and l each independently represent an integer of 1 to 5.

20. The reagent for biochemical measurements according to claim 17, wherein A in formula (1) is a linear or branched alkyl group having 12 to 28 carbon atoms.

21. The second repeating unit contains a structure represented by formula (2), and R in formula (2) ３ and R ４ The reagent for biochemical measurements according to claim 19, wherein is a methyl group.

22. The second repeating unit contains a structure represented by formula (3), and R in formula (3) ６ , R ７ and R ８ The reagent for biochemical measurements according to claim 19, wherein is a methyl group, and k and l are each 2.

23. The reagent for biochemical measurements according to claim 16, wherein the copolymer further comprises a third repeating unit having a molecular weight of 1,000 or less.

24. The reagent for biochemical measurements according to claim 23, wherein the third repeating unit is a repeating unit formed by any one monomer selected from the group consisting of (meth)acrylic acid, methyl (meth)acrylate, 2-methoxyethyl acrylate, and vinylpyrrolidone.

25. The reagent for biochemical measurements according to claim 16, wherein the antibody or fragment thereof is at least one selected from the group consisting of an antibody against an immunoglobulin or a fragment thereof, an anti-M protein antibody, an anti-cryoglobulin antibody, an anti-pyroglobulin antibody, an anti-rheumatoid factor antibody, an anti-complement antibody, and a decoy antibody.

26. The reagent for biochemical measurements according to claim 25, wherein the immunoglobulin or a fragment thereof is an immunoglobulin or a fragment thereof derived from any one animal selected from the group consisting of human, mouse, rat, rabbit, cow, goat, sheep, alpaca, dog, cat and bird.

27. The reagent for biochemical measurements according to claim 16, wherein the antibody or fragment thereof is derived from any one animal selected from the group consisting of mouse, rat, rabbit, cow, goat, and alpaca.

28. The reagent for biochemical measurements according to claim 16, wherein the antibody or fragment thereof is derived from a mouse.

29. The reagent for biochemical measurements according to claim 16, wherein the antibody or fragment thereof is an antibody or fragment thereof modified with a polymer compound.

30. The reagent for biochemical measurement according to claim 16, wherein the biochemical measurement is a homogeneous method.

31. The reagent for biochemical measurement according to claim 16, wherein the biochemical measurement is based on an antigen-antibody reaction.

32. The reagent for biochemical measurement according to claim 16, wherein the biochemical measurement is a latex immunoturbidimetric method.

33. A reagent for biochemical measurements, comprising: (a) an antibody or a fragment thereof; and (b) a copolymer containing (1) a first repeating unit having a linear or branched alkyl group with 12 to 40 carbon atoms, and (2) a second repeating unit having a cationic moiety and an anionic moiety, as a non-specific reaction inhibitor.

34. A reagent kit for biochemical measurements, comprising the reagent for biochemical measurements according to claim 16 or 17.

35. A biochemical measurement method comprising the following steps (1) to (4): (1) a step of mixing a measurement sample containing a substance to be measured with a non-specific reaction inhibitor containing an antibody or a fragment thereof as an active ingredient; (2) a step of mixing the measurement sample containing the substance to be measured with a non-specific reaction inhibitor containing, as an active ingredient, a copolymer including (i) a first repeating unit having a linear or branched alkyl group with 12 to 40 carbon atoms, and (ii) a second repeating unit having a cationic moiety and an anionic moiety; (3) a step of adding a substance with specific affinity for the substance to be measured; and (4) a step of detecting a signal resulting from the reaction of the substance to be measured with the specific affinity substance.

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