Antibody diluent and antibody product and kit prepared therefrom

Abstract

The invention discloses an antibody diluent, which belongs to the technical field of antibody detection. The antibody diluent is a buffer solution containing sugars, glycerol, a surfactant and a preservative, wherein the mass fraction of the sugars is 3% to 5%, and the volume fraction of the glycerol is 4% to 16%. The antibody diluent of the invention does not contain animal serum or animal serum albumin, eliminating biosafety and ethical risks, and its ingredients are simple, all of which are routine laboratory materials, easy to obtain, and thus easy to prepare. In addition, the antibody diluted by the antibody diluent of the invention can be stored for up to 2 weeks under 37°C thermal acceleration conditions, indicating that the antibody diluted by the antibody diluent of the invention has a longer storage period (more than 1 year).

Description

Technical Field

[0001] The present invention belongs to the technical field of antibody detection. Specifically, it relates to an antibody diluent, an antibody product prepared therefrom, and a kit. Background Art

[0002] An antibody diluent, that is, a solution used to dilute antibodies, is used to detect antigens (and their components) in samples with the prepared antibodies in experiments of antigen-antibody reactions such as WB, ELISA, IF, and IHC. The concentration (titer or potency) of commonly used antibody reagents is very high, and it needs to be diluted by an appropriate multiple before being used in the test reaction for detecting antigens.

[0003] Traditional antibody diluents are mostly composed of bovine serum or bovine serum albumin (BSA), preservatives, non-ionic surfactants, and buffers. However, antibody diluents containing bovine serum or BSA have many defects: First, there are various types of bovine serum and BSA on the market, such as low endotoxin grade, microbial grade, diagnostic analysis grade, etc. The preparation process is complex, and there are risks such as mad cow disease, viruses, and mycoplasmas; second, the presence of bovine serum or BSA in antibody diluents also poses biosafety and ethical risks; third, most diluents in the prior art have complex compositions. For example, the antibody diluent disclosed in patent CN109669040A also contains various components such as sodium caseinate and p-ethylaminophenol, and the antibody diluent disclosed in patent CN109991408A also contains various components such as polyvinylpyrrolidone and magnesium adenosine triphosphate, which increases the difficulty of preparation and may also affect subsequent detections. Summary of the Invention

[0004] In order to solve at least one of the above technical problems, the purpose of the present invention is to provide an antibody diluent without serum and BSA, and to ensure that the intensity, sensitivity, and stability of immunoassay using the diluted antibody are not affected or even better.

[0005] In order to achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0006] The first aspect of the present invention provides an antibody diluent, which is a buffer solution containing saccharides, glycerol, a surfactant, and a preservative, wherein the mass fraction of the saccharides is 3% - 5%, and the volume fraction of the glycerol is 4% - 16%.

[0007] Among them, saccharides and glycerol are used as antibody stabilizers, which can play a protective role to stabilize antibody activity.

[0008] In some embodiments of the present invention, the carbohydrate is selected from at least one of monosaccharides, disaccharides and polysaccharides. That is, it can be a monosaccharide, disaccharide or polysaccharide, or it can be a mixture of the same type of sugar or different types of sugars, such as a mixture of multiple monosaccharides, or a mixture of multiple disaccharides, or a mixture of one or more monosaccharides and one or more disaccharides. Among them, the monosaccharide is selected from the group including arabinose, ribose, xylose, lyxose, glucose, mannose, fructose, and galactose, the disaccharide is selected from the group including sucrose, trehalose, and lactose, and the polysaccharide is dextran. In some specific embodiments of the present invention, the carbohydrates include sucrose and trehalose, and the mass ratio of the two is sucrose: trehalose = 4:1.

[0009] In some embodiments of the present invention, the preservative is selected from one or more of the group including sodium azide, thimerosal, gentamicin, isothiazolinone preservatives and imidazolidinyl urea preservatives. Among them, the isothiazolinone preservatives mainly have two types, namely methylisothiazolinone (abbreviated as MIT) and methylchloroisothiazolinone (abbreviated as CIR). In the prior art, such preservatives are often used together in a ratio of 3:1, and the two mixed preservatives are called "kasone". The imidazolidinyl urea preservatives include diimidazolidinyl urea (bis (hydroxy) methyl imidazolidinyl urea, diazolidinyl urea) and DMDMH hydantoin.

[0010] In some embodiments of the present invention, the volume or mass fraction of the preservative is 0.1% to 0.5%.

[0011] In some preferred embodiments of the present invention, diazolidinyl urea is used as an antibacterial agent, and its principle is to release formaldehyde slowly, and it has an antibacterial effect on Gram-positive bacteria, Gram-negative bacteria, including Pseudomonas, and selectively inhibits yeast and mold. The diazolidinyl urea antibacterial agent is easy to use, stable in performance, safe and reliable, and the low concentration of formaldehyde released at the concentration used is non-irritating to the skin and mucous membranes, and does not pollute the environment. The antibacterial agent has a broad-spectrum antibacterial effect, can effectively inhibit most bacteria, and has a good antibacterial effect on Gram-negative bacteria. Its antibacterial ability is not affected by additives such as surfactants, proteins and enzymes in in vitro diagnostic reagents, and can be used to replace sodium azide in conventional solutions, and can be used in combination with commonly used antibacterial agents.

[0012] In some embodiments of the present invention, the surfactant is a nonionic surfactant selected from one or more of the group consisting of poloxamer, Surfynol surfactant, Triton, Tween, and Brij bio-based nonionic surfactants.

[0013] As a nonionic surfactant, the surface activity of poloxamer is related to its structure. The hydrophilic-lipophilic balance (HLB value) of poloxamer ranges from extremely hydrophobic Poloxamer 401 (HLB=0.5) to extremely hydrophilic Poloxamer 108 (HLB=30.5). The larger the proportion of polyoxyethylene segments, the higher the HLB value; when the proportion of polyoxyethylene segments is the same, the lower the relative molecular mass, the higher the HLB value. Selecting appropriate poloxamer to use alone or in combination can easily obtain the appropriate HLB value required for emulsified liquids.

[0014] Surfynol surfactant is an acetylenediol ethoxylate compound with low dynamic tension, low foam, low HLB value and other characteristics, and has excellent hydrophilicity, wetting and defoaming properties.

[0015] Triton is a commonly used nonionic surfactant. It is a colorless or almost transparent viscous liquid. It is soluble in water, toluene, xylene and ethanol, but insoluble in petroleum ether. The commonly used ones are Triton-100 and Triton-114. Triton-100 is polyethylene glycol monooctylphenyl ether, and Triton-114 is diethylene glycol mono[(1,1,3,3-tetramethylbutyl)phenyl] ether.

[0016] Tween (or polysorbate) is a non-ionic surfactant with a peculiar smell, warm and slightly bitter. It is a series of partial fatty acid esters of polyoxyethylene sorbitan. It is widely used as an emulsifier and solubilizer for oily substances. Polysorbate is generally considered to be a non-toxic and non-irritating material.

[0017] The Brij nonionic surfactant series is derived from naturally derived primary fatty alcohol ethoxylates. For example, Brij 35 is a stable Brij-35 surfactant solution for various protein methods. Brij 35 is most commonly used as a cell lysis buffer component and surfactant for various HPLC applications.

[0018] In some embodiments of the present invention, the volume or mass fraction of the non-ionic surfactant is 0.1% to 0.5%.

[0019] In some preferred embodiments of the present invention, Tween is selected as the surfactant, which can achieve unexpected technical effects. More preferably, the Tween is Tween-20.

[0020] In some embodiments of the present invention, the buffer is a PBS buffer. In some specific embodiments of the present invention, the PBS buffer is prepared as follows: 8.0 parts of sodium chloride, 0.2 parts of potassium chloride, 2.9 parts of disodium hydrogen phosphate dodecahydrate and 0.2 parts of potassium dihydrogen phosphate are weighed and dissolved in 800 parts of purified water, and the pH value is adjusted to 7.2-7.6, preferably 7.4, with 1M sodium hydroxide solution, and finally purified water is added to make the volume 1000 parts, and then filtered with a 0.22μm filter membrane and stored for later use.

[0021] In some other embodiments of the present invention, the buffer is a Tris-HCl buffer. In some specific embodiments of the present invention, the pH value of the Tris-HCl buffer is 7.2-7.6, preferably, 7.4.

[0022] In the present invention, Tris-HCl buffer is used as the buffer solvent, which has simpler ingredients and is easier to prepare than PBS buffer, making the preparation process of the antibody diluent faster, more convenient and easier to operate.

[0023] In some embodiments of the present invention, the antibody diluent is a Tris-HCl buffer containing 3% to 5% sugar by mass, 0.1% to 0.5% diazolidinyl urea by volume, 0.01% to 0.1% Tween by volume, and 4% to 16% glycerol by volume.

[0024] In some specific embodiments of the present invention, the antibody diluent is a Tris-HCl buffer containing 4% by mass of sugars, 0.2% by mass of diazolidinyl urea, 0.05% by volume of Tween, and 8% by volume of glycerol.

[0025] In other specific embodiments of the present invention, the antibody diluent is a Tris-HCl buffer containing 3.2% sucrose by mass, 0.5% trehalose by mass, 0.2% diazolidinyl urea by mass, 0.05% Tween by volume, and 8% glycerol by volume.

[0026] The second aspect of the present invention provides an antibody product, which is obtained by diluting an antibody with any antibody diluent described in the first aspect of the present invention.

[0027] In some embodiments of the invention, the antibody is a monoclonal antibody to Ki-67, CD68, CD3 or PSA.

[0028] The third aspect of the present invention provides a kit for immunohistochemical detection, comprising any antibody diluent described in the first aspect of the present invention or any antibody product described in the second aspect of the present invention.

[0029] In some embodiments of the present invention, the kit further comprises an antibody. In some specific embodiments of the present invention, the antibody is premixed with the antibody diluent. In some embodiments of the present invention, the kit further comprises a negative quality control sample and / or a positive quality control sample.

[0030] In some embodiments of the present invention, the kit further comprises a substrate solution and / or a stop solution.

[0031] The fourth aspect of the present invention provides a method for preparing any one of the antibody diluents described in the first aspect of the present invention, comprising the steps of mixing the sugar, preservative, surfactant, glycerol and buffer and stirring the mixture evenly.

[0032] In some embodiments of the present invention, sugars, preservatives, surfactants and glycerol may also be added to the buffer solution simultaneously or separately and mixed. Of course, those skilled in the art may prepare the antibody diluent in any manner, but all fall within the scope of the present invention.

[0033] Beneficial effects of the present invention

[0034] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0035] The antibody diluent of the invention does not contain animal serum or animal serum albumin, thereby eliminating biosafety and ethical risks.

[0036] The antibody diluent of the present invention has simple ingredients, all of which are conventional laboratory materials and are easy to obtain, so it is easy to prepare.

[0037] The antibodies diluted with the antibody diluent of the present invention can be stored for up to 2 weeks under the heat accelerated condition of 37° C., indicating that the antibodies diluted with the antibody diluent of the present invention have a longer storage period (more than 1 year). BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 The staining results after PSA antibody was diluted with antibody diluent #1 and stored at 2-8°C for 2 weeks in Example 3 of the present invention are shown.

[0039] Figure 2 The staining results after PSA antibody was diluted with antibody diluent #1 and stored at 37° C. for 2 weeks in Example 3 of the present invention are shown.

[0040] Figure 3 The staining results after PSA antibody was diluted with antibody diluent #2 and stored at 2-8°C for 2 weeks in Example 3 of the present invention are shown.

[0041] Figure 4The staining results after PSA antibody was diluted with antibody diluent #2 and stored at 37° C. for 2 weeks in Example 3 of the present invention are shown.

[0042] Figure 5 The staining results after the PSA antibody was diluted with antibody diluent 5 and stored at 2-8° C. for 2 weeks in Example 3 of the present invention are shown.

[0043] Figure 6 The staining results after PSA antibody was diluted with antibody diluent #5 and stored at 37° C. for 2 weeks in Example 3 of the present invention are shown.

[0044] Figure 7 The staining results after PSA antibody was diluted with antibody diluent #8 and stored at 2-8°C for 2 weeks in Example 3 of the present invention are shown.

[0045] Figure 8 The staining results after PSA antibody was diluted with antibody diluent #8 and stored at 37° C. for 2 weeks in Example 3 of the present invention are shown. DETAILED DESCRIPTION

[0046] Unless otherwise indicated, implied from the context, or customary in the prior art, all parts and percentages in this application are based on weight, and the test and characterization methods used are all current as of the filing date of this application. Where applicable, the contents of any patent, patent application or publication referred to in this application are fully incorporated herein by reference, and their equivalent patent families are also incorporated by reference, especially the definitions of synthesis techniques, product and processing designs, polymers, comonomers, initiators or catalysts disclosed in these documents in the art. If the definition of a specific term disclosed in the prior art is inconsistent with any definition provided in this application, the definition of the term provided in this application shall prevail.

[0047] Numerical ranges in this application are approximate values, so unless otherwise specified, they may include numerical values ​​outside the range. Numerical ranges include all numerical values ​​from the lower limit to the upper limit increased by 1 unit, provided that there is an interval of at least 2 units between any lower value and any higher value. For example, if the recorded component, physical or other properties (such as molecular weight, melt index, etc.) are 100 to 1000, it means that all single values ​​are clearly listed, such as 100, 101, 102, etc., and all sub-ranges, such as 100 to 166, 155 to 170, 198 to 200, etc. For a range comprising a numerical value less than 1 or comprising a fraction greater than 1 (such as 1.1, 1.5, etc.), 1 unit is appropriately regarded as 0.0001, 0.001, 0.01 or 0.1. For a range comprising a single digit less than 10 (such as 1 to 5), 1 unit is usually regarded as 0.1. These are only specific examples of what is intended, and all possible combinations of numerical values ​​between the lowest value and the highest value enumerated are to be considered to be expressly stated in this application.

[0048] When used with respect to chemical compounds, unless expressly specified otherwise, the singular includes all isomeric forms and vice versa (e.g., "hexane" includes all isomers of hexane, individually or collectively). In addition, nouns using "a," "an," or "the" also include their plural forms unless expressly specified otherwise.

[0049] The terms "comprising", "including", "having" and their derivatives do not exclude the presence of any other components, steps or processes, and are irrelevant to whether these other components, steps or processes are disclosed in this application. To eliminate any doubt, unless explicitly stated, all compositions using the terms "comprising", "including", or "having" in this application may include any additional additives, adjuvants or compounds. On the contrary, except for those necessary for operating performance, the term "essentially consisting of..." excludes any other components, steps or processes from the scope of any description of the term below. The term "consisting of..." does not include any components, steps or processes that are not specifically described or listed. Unless explicitly stated, the term "or" refers to the listed individual members or any combination thereof.

[0050] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments.

[0051] Example

[0052] The following examples are used to demonstrate preferred embodiments of the present invention. It will be appreciated by those skilled in the art that the techniques disclosed in the following examples represent techniques discovered by the inventors that can be used to implement the present invention and therefore can be considered as preferred embodiments of the present invention. However, it will be appreciated by those skilled in the art based on this specification that many modifications may be made to the specific embodiments disclosed herein and still achieve the same or similar results without departing from the spirit or scope of the present invention.

[0053] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs, and the disclosure and materials cited therein are hereby incorporated by reference.

[0054] Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many technical equivalents to the specific embodiments of the invention described herein. Such equivalents are intended to be encompassed by the claims.

[0055] The molecular biology experimental methods not specifically described in the following examples are all carried out in accordance with the specific methods listed in the book Molecular Cloning Experiment Guide (4th Edition) (J. Sambrook, MR Green, 2017), or in accordance with the kits and product instructions. Other experimental methods are conventional methods unless otherwise specified. The instruments and equipment used in the following examples are conventional laboratory instruments and equipment unless otherwise specified; the experimental materials used in the following examples are purchased from conventional biochemical reagent stores unless otherwise specified.

[0056] Example 1 Preparation of Antibody Dilutions #1-#8

[0057] This embodiment provides 8 kinds of antibody diluents #1-#8, wherein antibody diluent #8 is a formula protected by Chinese invention patent ZL202110511412.1, and as a control in the present invention, it does not use sugar as a protein protective agent, but uses BSA as a protein protective agent. The specific formula is shown in Table 1.

[0058] Table 1 Antibody diluent #1-#8 formula

[0059]

[0060] The preparation method is as follows:

[0061] Accurately weigh or measure the material components except the buffer in the above table into a clean sterilized container, add the corresponding buffer (pH 7.4), stir well, filter with a 0.22μm filter membrane and store for later use.

[0062] The preparation method of 1× PBS buffer is as follows:

[0063] Weigh 8.0 g of sodium chloride, 0.2 g of potassium chloride, 2.9 g of disodium hydrogen phosphate dodecahydrate and 0.2 g of potassium dihydrogen phosphate, dissolve in 800 mL of purified water, adjust the pH value to 7.4 with 1 M sodium hydroxide solution, and finally add purified water to make up to 1 liter, filter with a 0.22 μm filter membrane and store for later use.

[0064] Example 2 Effect Detection of Antibody Dilutions #1-#8

[0065] 1. Antibody Dilution

[0066] The antibodies were diluted according to the appropriate dilutions using the antibody diluents #1-#8 prepared in Example 1. The antibody item numbers, clone numbers, and dilutions are shown in Table 2.

[0067] Table 2 Antibody information

[0068] Antibody Targets Part Number Clone number Dilution supplier ki-67 BX50128 BP6132 1:100 Hangzhou Bailing Biotechnology Co., Ltd. CD68 BX50031 BP6036 1:200 Hangzhou Bailing Biotechnology Co., Ltd. CD3 BX50034B BP6039 1:200 Hangzhou Bailing Biotechnology Co., Ltd. PSA BX50038B BP6043 1:200 Hangzhou Bailing Biotechnology Co., Ltd. Collagen Type IV BX50067 BP6072 1:200 Hangzhou Bailing Biotechnology Co., Ltd. CD30 BX50005 BP6012 1:200 Hangzhou Bailing Biotechnology Co., Ltd.

[0069] 2. Antibody detection

[0070] Place the slices containing tissue samples in a 62°C oven for 1 hour. Immerse the slides in two cylinders of dewaxing solution in a fume hood for 15 minutes each time. Immerse the slices in anhydrous ethanol, 95% ethanol, and 75% ethanol in turn, soaking each solution twice for 5 minutes each time. Take out the slices and rehydrate for 5 minutes. Place the slices in an antigen retrieval solution that has been preheated to a boiling state, keep it slightly boiling for 15 minutes, and take out the sample slices after returning to room temperature. Add 3% hydrogen peroxide solution and incubate at room temperature for 10 minutes to remove endogenous peroxidase. Incubate the slices with the above-diluted primary antibody and incubate at room temperature for 30 minutes. Add HRP-conjugated polymer secondary antibody and incubate at room temperature for 30 minutes. Add DAB colorimetric solution and incubate at room temperature for 2 minutes. After the color development is completed, perform hematoxylin counterstaining and dehydration to make it transparent. After the slices are taken out and blown dry, they are sealed with neutral gum.

[0071] 3. Staining results

[0072] The monoclonal antibodies were diluted with the antibody diluents #1-#8 prepared in the examples at appropriate dilutions, and then tissue staining was performed. The staining results are shown in Table 3.

[0073] Table 3 Monoclonal antibody names and corresponding tissue staining

[0074] Antibody Targets organize #1 #2 #3 #4 #5 #6 #7 #8 Ki-67 tonsil qualified qualified qualified qualified qualified Weak Background Background CD68 tonsil qualified qualified qualified Background qualified qualified Background Background CD3 tonsil qualified qualified qualified Background qualified qualified Background Background PSA Prostate cancer qualified qualified Weak qualified qualified Weak Background Negative Collagen Type IV kidney Weak Weak Weak Weak Weak Weak Weak qualified CD30 Hodgkin lymphoma Weak Weak Weak Weak Weak Weak Weak qualified

[0075] As can be seen from Table 3, for Ki-67, CD68, CD3 and PSA monoclonal antibodies, after dilution and detection using antibody diluent #1, antibody diluent #2 and antibody diluent #5, the staining of the four antibodies all met the requirements; after dilution and detection using antibody diluent #3, the staining of one antibody (PSA) was weak, and the staining of three antibodies met the requirements; after dilution and detection using antibody diluent #4, the staining of two antibodies (CD68 and CD3) showed background, and the staining of the other two antibodies met the requirements; after dilution and detection using antibody diluent #6, the staining of two antibodies (Ki-67 and PSA) was weak, and the staining of the other two antibodies met the requirements; after dilution and detection using antibody diluent #7, the staining of the four antibodies all showed background; after dilution and detection using antibody diluent #8, the staining of three antibodies showed background, and the staining result of one antibody (PSA) was negative. For Collagen Type IV and CD30 monoclonal antibodies, the staining results of the dilution tests using antibody diluents #1-#7 were all weak, while the results of the dilution tests using antibody diluent #8 all met the requirements, indicating that antibody diluents #1-#7 are not suitable for Collagen Type IV and CD30 monoclonal antibodies.

[0076] It can be seen that for Ki-67, CD68, CD3 and PSA monoclonal antibodies, the staining effect is better after diluting the antibodies with Antibody Diluent #1, Antibody Diluent #2 and Antibody Diluent #5.

[0077] Example 3 Antibody dilution heat acceleration experiment

[0078] The known document "Application of the Arrhenius Equation in Predicting the Shelf Life of In Vitro Diagnostic Reagents" proves that the accelerated stability test of liquid reagents can quickly determine the long-term storage shelf life of the reagents and shorten the reagent development cycle. Based on the research in this document, the present invention uses a comparison of the test after 2 weeks of thermal acceleration at 37°C and 2 weeks of storage at 2-8°C to simulate the long-term stability of the test reagent; based on this document, it is speculated that the test reagent can be thermally accelerated at 37°C for 2 weeks to simulate storage at 2-8°C for no less than 12 months.

[0079] The antibodies were diluted with antibody diluent #1, antibody diluent #2, and antibody diluent #5 prepared in Example 1 at appropriate dilutions, and then tested and compared at 37°C for 2 weeks and stored at 2-8°C for 2 weeks. Antibody diluent #8 was used as a control. The staining results are shown in Table 4.

[0080] Table 4 Comparison of thermal acceleration at 37°C for 2 weeks and storage at 2-8°C for 2 weeks

[0081]

[0082]

[0083] From the results in Table 4, it can be seen that the four antibodies diluted and stored in antibody diluent #1, antibody diluent #2, and antibody diluent #5 all met the staining requirements after being heat accelerated at 37°C for 2 weeks and stored at 2-8°C for 2 weeks. In contrast, after the antibodies stored in antibody diluent #8 were heat accelerated at 37°C for 2 weeks and stored at 2-8°C for 2 weeks, the staining of Ki-67, CD68, and CD34 antibodies all had background, and the PSA staining results were negative, which did not meet the requirements.

[0084] The staining results after diluting PSA antibody with antibody diluent #1, antibody diluent #2, antibody diluent #5 and antibody diluent #8, respectively, at 37°C for 2 weeks and at 2-8°C for 2 weeks were as follows: Figures 1 to 8 shown.

[0085] Depend on Figure 1 to Figure 6 It can be seen that the detection results of PSA monoclonal antibodies diluted with antibody diluent #1, antibody diluent #2, and antibody diluent #5 after 2 weeks of thermal acceleration at 37°C and 2 weeks of storage at 2-8°C are relatively ideal, and the staining effect of antibody diluent #5 is better (the staining intensity is more obvious compared with the background, and there is no non-specific staining). However, PSA monoclonal antibodies diluted and stored with antibody diluent #8 cannot be detected (the test results are negative) regardless of whether they are thermally accelerated at 37°C for 2 weeks or stored at 2-8°C for 2 weeks. The above results show that the antibody products prepared with antibody diluent #1, antibody diluent #2, and antibody diluent #5 can be stored at 2-8°C for up to one year.

[0086] In summary, the antibody diluent provided by the present invention can improve the strength, sensitivity and stability of immunohistochemical detection. The antibody diluent provided by the present invention can be used for diluting and preparing antibody products, and is particularly suitable for the production of immunohistochemical primary antibody reagents to improve the storage stability of immunohistochemical antibody reagents; the antibody product prepared therefrom can be stored for a long period of time (more than one year) at 2-8°C.

[0087] All documents mentioned in the present invention are cited as references in this application, just as each document is cited as reference individually. In addition, it should be understood that after reading the above teachings of the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the claims attached to this application.

Claims

1. Use of a buffer in the preparation of an antibody product, characterized in that, the buffer is used as an antibody diluent, and the buffer contains only saccharides, glycerol, a surfactant and a preservative. The mass fraction of the saccharides is 3% - 5%. The saccharides are sucrose and trehalose, and the mass ratio of the two is sucrose:trehalose = 4:

1. The volume fraction of the glycerol is 4% - 16%. The antibody is a monoclonal antibody of Ki-67, CD68, CD3 or PSA. The buffer is a PBS buffer or a Tris-HCl buffer. The surfactant is Tween-20, and its volume fraction is 0.01% - 0.1%.

2. The use according to claim 1, characterized in that, the preservative is selected from one or more of the group consisting of sodium azide, thimerosal, gentamicin, isothiazolinone preservatives and imidazolidinyl urea preservatives, and its volume or mass fraction is 0.1% - 0.5%.

3. The use according to claim 1, characterized in that, the pH value of the antibody diluent is 7.2 - 7.

6.

4. An antibody product, characterized in that, the antibody product is obtained by diluting an antibody with the buffer according to any one of claims 1 - 3, and the antibody is a monoclonal antibody of Ki-67, CD68, CD3 or PSA.

5. A kit for immunohistochemical detection, characterized in that, it includes the antibody product according to claim 4.

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