阅读说明：本技术 一种抗原修复液及采用其制备的细胞爬片、以及细胞爬片的制备方法和应用 (Antigen repairing liquid, cell climbing sheet prepared by using antigen repairing liquid, and preparation method and application of cell climbing sheet ) 是由 闫亚平 郝文斌 封雪 李科 于 2021-09-01 设计创作，主要内容包括：本发明公开了一种抗原修复液及采用其制备的细胞爬片、以及细胞爬片的制备方法和应用,属于生物技术领域。该抗原修复液是浓度为1～1000mM的铵盐缓冲液,所述铵盐缓冲液能够与醛基反应。本发明首次将铵盐缓冲液用于固定后细胞的抗原修复上,有效的恢复或暴露被屏蔽或封闭的抗原(或抗原表位),因此避免了检测当中假阴性结果的出现,增加了检测的正确率,同时有助于寻找的新的自身抗体。本发明还公开了采用上述抗原修复液制备细胞爬片的方法,具有操作时间短,步骤简单、细胞不掉片、实验结果一致性好等特点,制备得到的细胞爬片保质期长,抗原的信号在较长的一段时间维持不变。(The invention discloses an antigen repairing solution, a cell slide prepared by the antigen repairing solution, and a preparation method and application of the cell slide, and belongs to the technical field of biology. The antigen retrieval liquid is an ammonium salt buffer solution with the concentration of 1-1000 mM, and the ammonium salt buffer solution can react with aldehyde groups. The invention uses the ammonium salt buffer solution for the antigen restoration of the fixed cells for the first time, and effectively restores or exposes the shielded or blocked antigen (or epitope), thereby avoiding the occurrence of false negative results in the detection, increasing the accuracy of the detection and being beneficial to searching for new autoantibodies. The invention also discloses a method for preparing the cell slide by adopting the antigen repairing liquid, which has the characteristics of short operation time, simple steps, no cell drop, good consistency of experimental results and the like, the quality guarantee period of the prepared cell slide is long, and the signal of the antigen is kept unchanged for a long period of time.)

1. The antigen retrieval solution is characterized by being an ammonium salt buffer solution with the concentration of 1-1000 mM, wherein the ammonium salt buffer solution can react with aldehyde groups.

2. The antigen retrieval fluid of claim 1, wherein sodium dodecyl sulfate is further added to the ammonium salt buffer solution, and the sodium dodecyl sulfate accounts for 0.025-0.25% of the mass of the antigen retrieval fluid.

3. The antigen retrieval solution of claim 1 or 2, wherein the ammonium salt comprises NH₄Cl、(NH₄)₂SO₄、NH₄NO₃、(NH₄)₂CO₃、NH₄COOH、NH₄HCO₃And tris (hydroxymethyl) aminomethane.

4. A method for preparing a cell slide by using the antigen retrieval solution according to any one of claims 1 to 3, comprising the steps of:

1) fixing the growing cell climbing sheet by using a formaldehyde solution, a paraformaldehyde solution or a glutaraldehyde solution, and washing after fixing;

2) stopping the slide processed in the step 1) by using the antigen retrieval solution;

3) washing the cell slide processed in the step 2) by using a phosphate buffer solution;

4) drying and storing the climbing tablets washed in the step 3) to obtain the cell climbing tablets.

5. The method for preparing cell slide according to claim 4, wherein the growing cell slide is prepared by the following steps:

transferring the cell-paved slide into a recombinant vector through transient transfection, and obtaining the cell after the cell grows for 24-72 hours; alternatively, the first and second electrodes may be,

recovering the stable cell line obtained by stable transfection, spreading on a creeping sheet, and obtaining the cell after the cell density grows to be more than or equal to 80%.

6. The method for preparing a cell slide according to claim 4, wherein in step 1):

when the concentration of the used formaldehyde, paraformaldehyde or glutaraldehyde is more than 0.5%, the use of the repair liquid can recover positive signals, and the shelf life is prolonged;

when the concentration of the used formaldehyde, paraformaldehyde or glutaraldehyde is less than or equal to 0.5%, the shelf life of the repair liquid can be prolonged.

7. The method for preparing a cell slide according to claim 4, wherein the terminating treatment time in step 2) is 1-10 min.

8. The method for preparing the cell slide according to claim 4, wherein in the step 4), the drying method comprises oven drying, microwave oven drying, metal bath drying, and hot air drying, the drying time is only required for completely drying the cell slide, and the dried cell slide is stored in a sealed manner at a temperature of less than or equal to 4 ℃.

9. The cell climbing sheet prepared by the method for preparing the cell climbing sheet according to any one of claims 4 to 8.

10. Use of the cell slide of claim 9 for the preparation of an immunofluorescence autoantibody diagnostic kit.

Technical Field

The invention belongs to the technical field of biology, and relates to an antigen repairing liquid, a cell slide prepared from the antigen repairing liquid, and a preparation method and application of the cell slide.

Background

In the field of bioscience, immunocytochemistry is used to detect antigens in cells and tissues, providing important information for localization and characterization of antigens, and thus, is widely used in diagnosis and differential diagnosis. Since tissue or cell slide is fixed with chemical reagents during the manufacturing process, part of the fixed antigen may not be detected during subsequent staining, thus creating the concept of "shielding or blocking" of the antigen, in which case the antigen (or a specific epitope) is hidden, thus rendering the antibody recognizing the antigen (or specific epitope) unable to bind to it. In order to solve the above problems and to better expose the antigen, the method adopted is to perform antigen retrieval.

At present, the main antigen repairing methods comprise thermal repairing and enzymatic repairing, the two methods are more applied to immunohistochemistry with tissues as carriers, and research and application are less aiming at repairing by an immunofluorescence method with cells as carriers. The reason for this may be: (1) the cell climbing sheet is easy to fall off at high temperature in the thermal repair, the time consumption is long, and the operation is complicated; (2) enzymatic repair is susceptible to factors such as the type of enzyme, the acting time, the acting temperature and the like, so that the result consistency is poor; (3) even when the repair is carried out by a thermal repair method or an enzymatic method, it is difficult to achieve a good repair effect. In 1992, Soltypes B J et al applied SDS to antigen retrieval of fixed cells based on the denaturation of sodium dodecyl benzene sulfonate (SDS) (interactions of endogenous antibodies, mitochondria, intercalaries, and microtubulas & ndash; a square fluorescence labeling study. biochem Cell Biol,70: 1174. sup. 1186.). Robinson in his paper indicated that although SDS can repair some epitopes, not all epitopes can be repaired (J.M.Robinson, D.D.Vandr é. Department Antigen retrieval in cells and properties: enhancement with a sodium pathogen subset. Histochem Cell Biol 2001,116: 119-. The use of SDS for antigen retrieval, if SDS cannot be washed thoroughly, will result in denaturation of the incubated antibody, which in turn will affect the experimental results.

The main problems of the current detection technology are as follows:

(1) the immunofluorescence method using cells as a substrate leads to the blocking of antigens (or specific epitopes) due to the use of a fixing agent, thus seriously reducing the accuracy and sensitivity of detection;

(2) the immunofluorescence method using cells as a substrate blocks antigens (or specific epitopes) due to the use of a fixing agent, so that the application of the method in searching for new autoantibodies is limited;

(3) the existing method for repairing the antigen has complicated operation steps, and the repairing conditions and the repairing result are influenced by various factors, so that the existing method is not beneficial to obtaining a stable and good experimental result.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention aims to provide an antigen retrieval solution, a cell slide prepared by the antigen retrieval solution, a preparation method of the cell slide and application of the cell slide.

In order to achieve the purpose, the invention adopts the following technical scheme to realize the purpose:

the invention discloses an antigen retrieval solution, which is an ammonium salt buffer solution with the concentration of 1-1000 mM, wherein the ammonium salt buffer solution can react with aldehyde groups.

Preferably, sodium dodecyl sulfate is further added into the ammonium antigen repairing liquid, and the sodium dodecyl sulfate accounts for 0.025-0.25% of the mass of the antigen repairing liquid.

Preferably, the ammonium salt comprises NH₄Cl、(NH₄)₂SO₄、NH₄NO₃、(NH₄)₂CO₃、NH₄COOH、NH₄HCO₃And tris (hydroxymethyl) aminomethane.

The invention also discloses a method for preparing a cell slide by adopting the antigen repairing liquid, which comprises the following steps:

1) fixing the growing cell climbing sheet by using a formaldehyde solution, a paraformaldehyde solution or a glutaraldehyde solution, and washing after fixing;

2) stopping the slide processed in the step 1) by using the antigen retrieval solution;

3) washing the cell slide processed in the step 2) by using a phosphate buffer solution;

4) drying and storing the climbing tablets washed in the step 3) to obtain the cell climbing tablets.

Preferably, the growing cell climbing sheet is prepared by the following steps:

transferring the cell-paved slide into a recombinant vector through transient transfection, and obtaining the cell after the cell grows for 24-72 hours; alternatively, the first and second electrodes may be,

recovering the stable cell line obtained by stable transfection, spreading on a creeping sheet, and obtaining the cell after the cell density grows to be more than or equal to 80%.

Preferably, in step 1):

when the concentration of the used formaldehyde, paraformaldehyde or glutaraldehyde is more than 0.5%, the use of the repair liquid can restore the positive signal and prolong the shelf life;

when the concentration of the used formaldehyde, paraformaldehyde or glutaraldehyde is 0.5% or less than 0.5%, the use of the repair liquid can prolong the shelf life.

Preferably, in the step 2), the treatment termination time is 1-10 min.

Preferably, in the step 4), the drying method comprises oven drying, microwave oven drying, metal bath drying, hot air blowing and other available drying instruments, the drying time is only required to completely dry the cell slide, and the dried cell slide is stored in a sealed manner at the temperature of less than or equal to 4 ℃.

The invention also discloses the cell climbing sheet prepared by the method for preparing the cell climbing sheet.

The invention also discloses application of the cell slide in preparing an immunofluorescence autoantibody diagnostic kit.

Compared with the prior art, the invention has the following beneficial effects:

the antigen repairing liquid disclosed by the invention is used for repairing the antigen of a fixed cell by using the ammonium salt buffer solution for the first time, the ammonium salt can generate a neutralization reaction with the fixing agent with aldehyde group, the shielded or closed antigen (or antigen epitope) is effectively recovered or exposed, the occurrence of false negative results in detection is avoided, the detection accuracy is increased, and meanwhile, the novel autoantibody is also beneficial to searching.

Further preferably, the ammonium salt buffer solution is mixed with SDS, and the mixture has good effect on repairing cells and tissues.

The invention also discloses a method for preparing the cell slide by adopting the antigen repairing liquid, which has the characteristics of short operation time, simple steps, no cell drop, good consistency of experimental results and the like, the prepared cell slide has long quality guarantee period, the signal of the antigen is kept unchanged for a long period of time, and the cell slide can be applied to an immunofluorescence autoantibody diagnostic kit and the research, development and application of the diagnostic kit are expanded.

Drawings

FIG. 1 is a fluorescent photograph of cell slides fixed with different concentrations of formaldehyde;

FIG. 2 shows a graph showing a band passing through 50mM (NH4)₂SO4 repaired cell slide fluorescence photographs fixed with formaldehyde at different concentrations;

FIG. 3 is a fluorescent photograph of a cell slide repaired by adding different kinds of antigen repairing solutions;

FIG. 4 is a fluorescent photograph of cell slide repaired by 0.1% trypsin and 0.4% pepsin, respectively, in comparative example 1;

FIG. 5 is a fluorescent photograph of cell slide repaired by thermal repairing method in comparative example 2.

Detailed Description

In order to make the technical solutions of the present invention better understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the invention described herein are capable of operation in sequences other than those illustrated or described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

The invention is described in further detail below with reference to the accompanying drawings:

example 1

1. Obtaining of recombinant vectors

Carrying out plasmid big extraction on the recombinant vector pCDNA3.1-MOG constructed in the laboratory for later use;

2. cell transfection

(1)293T cell culture: preparing a 10% FBS-DMEM high-sugar medium by a DMEM high-sugar medium and FBS according to a ratio of 9:1, carrying out passage to a 6-well plate according to a ratio of 1: 5-1: 6 when cells are fully paved, paving a cell slide with the diameter of 1cm in each well, placing the cell slide at 37 ℃ and 5% CO₂Overnight culture in a cell culture box;

(2) gene transfection: and (3) transfecting the pCDNA3.1-MOG plasmid extracted in the step (1) according to a PEI transfection method, replacing a fresh culture solution after 4-6 hours of transfection, and fixing and dyeing after 48 hours to terminate growth.

Example 2

The experimental procedure was as follows:

1. washing: the cell slide transfected with plasmid pCDNA3.1-MOG of example 1 was washed 2 times with PBS;

2. fixing: adding formaldehyde with different concentrations for fixation for 4 min; the concentration of formaldehyde with different concentrations is 0.5%, 1.5%, 2.5%, 3.5%, 4.5% and 5.5% respectively.

3. Washing: washing the cell slide after fixing the formaldehyde for 3 times by using PBS;

4. drying: drying by using a 37 ℃ oven;

5. primary antibody incubation: incubating the positive sample for 1 hour;

6. washing: wash 3 times with PBST for 5min each;

7. and (3) secondary antibody incubation: incubating for 40min for the second antibody;

8. washing: wash 3 times with PBST for 5min each;

9. and (4) observing results: the results were observed under a fluorescent microscope.

The experimental results are as follows: the results of fixing formaldehyde at different concentrations are shown in FIG. 1, and it is found from the experimental results that the higher the formaldehyde concentration, the more serious the blocking degree of the signal.

Example 3

Experimental procedure

1. Taking the cell slide fixed by formaldehyde with different concentrations in the step 2 of the embodiment 2, and washing for 3 times by PBS;

2. 50mM (NH) was added₄)₂SO₄Stopping for 4min by using a buffer solution;

3. washing: the cell slide after termination was washed 3 times with PBS;

4. drying: drying by using a 37 ℃ oven;

5. primary antibody incubation: incubating the positive sample for 1 hour;

6. washing: wash 3 times with PBST for 5min each;

7. and (3) secondary antibody incubation: incubating for 40min for the second antibody;

8. washing: wash 3 times with PBST for 5min each;

9. and (4) observing results: the results were observed under a fluorescent microscope.

The experimental results are as follows: as can be seen from FIG. 2, the formaldehyde slides fixed at different concentrations passed 50mM (NH) compared to example 1₄)₂SO₄The positive signal of cell slide after termination is obviously enhanced, which indicates (NH)₄)₂SO₄Has good effect on the repair of MOG antigen.

Example 4

1. 3.5% formaldehyde fixed cell slide of step 2 of example 2 was taken and washed 3 times with PBS;

2. respectively using 50mM different ammonium salt buffer solution, 0.25% Sodium Dodecyl Sulfate (SDS), 0.25% sodium dodecyl sulfate and (NH)₄)₂SO₄Mixed buffer of (2), finallyStopping for 4 min;

wherein the different types of ammonium salt buffer and ammonium salt include (NH)₄)₂SO₄、NH₄Cl、NH₄NO₃、(NH₄)₂CO₃、NH₄COOH and Tris;

3. washing: the cell slide after termination was washed 3 times with PBS;

4. drying: drying by using a 37 ℃ oven;

5. primary antibody incubation: incubating the positive sample for 1 hour;

6. washing: wash 3 times with PBST for 5min each;

7. and (3) secondary antibody incubation: incubating for 40min for the second antibody;

8. washing: wash 3 times with PBST for 5min each;

9. and (4) observing results: the results were observed under a fluorescent microscope.

The experimental results are as follows: as can be seen from FIG. 3, NH in comparison with example 1₄Cl、(NH₄)₂SO₄、NH₄NO₃、(NH₄)₂CO₃、NH₄COOH, Tris, sodium dodecyl sulfate buffer solution, (NH)₄)₂SO₄The mixed buffer solution of the sodium dodecyl sulfate and the sodium dodecyl sulfate has good antigen repairing effect and obvious positive signals.

Example 5

0.5% formaldehyde-fixed cell-slide from example 2 after drying, 50mM (NH) from example 3₄)₂SO₄The repaired formaldehyde fixing slide with 0.5 percent is placed at different temperatures, namely, 37 ℃, 4 ℃ and-20 ℃ for storage, and the slide is taken out periodically to verify a positive signal. The results are shown in table 1 below:

TABLE 1

As can be seen from Table 1, the duration of the positive signal is significantly increased in cell climbing after termination with ammonium salts.

Comparative example 1

1. 3.5% formaldehyde fixed cell slide of step 2 of example 2 was taken and washed 3 times with PBS;

2. preheating 0.1% trypsin solution (prepared from PBST and containing 0.2% tween20) and 0.4% pepsin solution (prepared from PBST and containing 0.2% tween20) in a 37 ℃ incubator in advance, preheating the fixed slide in the 37 ℃ incubator, adding the enzyme solution to the cell slide when the temperature is about 37 ℃, and digesting for 20min at 37 ℃;

3. washing: washing the reprint after enzyme digestion with PBS 3 times;

4. drying: drying by using a 37 ℃ oven;

5. primary antibody incubation: incubating the positive sample for 1 hour;

6. washing: wash 3 times with PBST for 5min each;

7. and (3) secondary antibody incubation: incubating for 40min for the second antibody;

8. washing: wash 3 times with PBST for 5min each;

9. and (4) observing results: the results were observed under a fluorescent microscope.

The experimental results are as follows: referring to FIG. 4, it can be seen from FIG. 4 that the positive signal after enzymatic repair is not significantly improved compared to the 3.5% formaldehyde fixed cell slide of example 2.

Comparative example 2

1. 3.5% formaldehyde fixed cell slide of step 2 of example 2 was taken and washed 3 times with PBS;

2. antigen retrieval buffer (100mM Tris, 5% [ w/v ] urea, pH9.5) was pre-warmed to 95 ℃. The specific method comprises the following steps: placing a glass slide staining jar filled with buffer solution in a water bath kettle, wherein the temperature of the water bath kettle is set to be 95 ℃;

3. heating the cell slide at 95 ℃ for 10 minutes;

4. washing: washing the repaired slide with PBS 3 times;

5. drying: drying by using a 37 ℃ oven;

6. primary antibody incubation: incubating the positive sample for 1 hour;

7. washing: wash 3 times with PBST for 5min each;

8. and (3) secondary antibody incubation: incubating for 40min for the second antibody;

9. washing: wash 3 times with PBST for 5min each;

10. and (4) observing results: the results were observed under a fluorescent microscope.

The experimental results are as follows: referring to fig. 5, it can be seen from fig. 5 that although the signal of the thermal restoration method is clearly restored, the cell slide-off is serious.

The above-mentioned contents are only for illustrating the technical idea of the present invention, and the protection scope of the present invention is not limited thereby, and any modification made on the basis of the technical idea of the present invention falls within the protection scope of the claims of the present invention.