Arginase-1 Product Manual

Arginase-1 Instruction Manual

Manual No.:MyR1-ARG1253

(This antibody is for research use only, not for clinical diagnosis)

【Product Name】

【Product No. and Packaging Specifications】

【Intended Use】

This antibody reagent is suitable for immunohistochemical staining of formalin-fixed, paraffin-embedded human tissue sections to identify the expression of Arginase-1 protein in tissues.

As a key enzyme in the urea cycle, Arginase-1 is highly specifically expressed in hepatocytes of normal liver tissue, while cholangiocytes, sinusoidal endothelial cells, Kupffer cells and vascular endothelial cells do not express it. It is expressed in malignantly transformed liver tissue, especially in well-differentiated and moderately differentiated hepatocellular carcinoma. The combined use of antibody panels including CD10, pCEA, AFP, HepPar-1, glypican-3, and Arginase-1 is of great significance for the research of benign liver lesions, well-differentiated hepatocellular carcinoma, poorly differentiated hepatocellular carcinoma, and metastatic tumors.

(Note: Interpretation of immunohistochemical staining results should be combined with pathological morphology and other data, and the staining results are not intended as a diagnostic indicator.)

【Main Components】

Monoclonal rabbit anti-human Arginase-1 protein antibody, Clone No.: MyR1-ARG1, Immunoglobulin isotype: IgG. This product is tissue culture supernatant, containing 0.05 mol/L Tris-HCl (pH 7.2), 0.015 mol/L sodium azide (NaN3) and protein stabilizers.

【Storage Conditions and Validity Period】

The reagent should be stored in the dark at 2-8℃ (not below 0℃) and immediately returned to the 2-8℃ refrigerator after each use. The validity period is indicated on the outer packaging of the product (Note: Improper storage of the reagent as specified above may affect its performance.)

【Principle of Immunohistochemical Staining】

In immunology, antigen and antibody molecules specifically bind due to structural complementarity and affinity. Based on this principle, the antibody will bind to specific antigens/proteins in the tested human tissues and cells. Subsequently, the enzyme chromogen labeled on the antibody is developed through redox chemical reactions, thereby showing the distribution of antigens in tissues and cells.

Firstly, this antibody specifically binds to the antigen on the tested tissue; secondly, the enzyme-labeled anti-mouse/rabbit IgG polymer recognizes the antibody that has bound to the antigen; thirdly, the chromogenic substrate is added, and horseradish peroxidase on the polymer can catalyze the decomposition of H2O2 in the DAB chromogenic solution, oxidizing benzidine to benzidine imine, resulting in yellow or brown-yellow staining at the antigen sites in the tissue sections; finally, the samples are counterstained and mounted. The presence and expression of the antigen on the tissue sections are inferred by observing the staining under a microscope.

【Sample Requirements】

Fresh biopsy or surgical specimens should be fixed with 10% neutral formalin solution for 6-24 hours, and processed into wax blocks by sampling, dehydration and paraffin embedding in accordance with technical specifications. Wax blocks can be stored at room temperature for a valid period of 5 years.

Section the specimen wax blocks into 3-5μm thick slices, adhere them to anti-drop slides, and bake the slides in a constant temperature incubator at 58-60℃ for 1 hour for staining. Unused unstained slides can be stored at room temperature (15-25℃) (preferably with anti-oxidation treatment). For good reproduction of antigen distribution in tissue sections, it is recommended to complete immunohistochemical staining within 7 days.

【Staining Method】

The following are the recommended configuration and procedures for manual immunohistochemistry. If automated immunohistochemical instruments are used for staining, adjustments should be made according to different instruments and chromogenic kits. A complete immunohistochemical experiment should include positive tissue control, negative tissue control and blank (or negative) reagent control. Evaluation and verification of experimental results should refer to 【Quality Control】 and 【Interpretation of Staining Results】.

1) Required Instruments and Equipment:

Induction cooker, stainless steel pot, timer, incubation wet box, staining rack, staining jar, coverslips, optical microscope (40×-200×), wash bottle, absorbent paper, pipette, etc.

2) Reagent and Material Preparation:

No dilution is required for the working solution of this antibody reagent before use. If it is a concentrate, it is recommended to dilute it into a working solution with PBS buffer or antibody diluent at a ratio of 1:100-1:200 before use. For the preparation of PBS buffer, antigen retrieval solution, secondary antibody, DAB chromogenic solution and other reagents, please refer to the respective product instruction manuals.

Other materials required for the experiment are as follows:

PBS buffer (pH7.2-7.4), Tris-EDTA antigen retrieval solution (pH9.0), endogenous peroxidase blocker, HRP-labeled anti-mouse/rabbit IgG polymer, DAB chromogenic solution, hematoxylin staining solution, blank (or negative) control reagent, positive and negative control tissue sections, xylene or xylene substitute, ethanol (anhydrous, 95%, 85%), distilled water or deionized water, mounting medium (e.g., neutral gum), anti-drop slides, coverslips, etc.

3) Experimental Temperature Conditions: Room temperature 18℃-28℃.

4) Experimental Procedures:

A. Deparaffinization and Hydration

(1) Immerse the tissue sections in 2 jars of fresh xylene successively for 10 minutes each;

(2) Immerse the tissue sections in anhydrous ethanol, 95% ethanol and 85% ethanol successively for 5 minutes each;

(3) Rinse gently with distilled water for 1 minute, and soak in distilled water for retrieval after rinsing.

B. Antigen Retrieval (High Pressure Retrieval)

(1) Put the prepared Tris-EDTA antigen retrieval solution (pH9.0) into a pressure cooker, place the deparaffinized and hydrated tissue sections on a high-temperature resistant plastic slide rack, and immerse them in the retrieval solution to ensure the tissue sections are completely submerged;

(2) Cover the pressure cooker and fasten the pressure valve, heat on high fire (1600W/210℃) until steam is emitted, start timing for 2 minutes from the emission of steam and switch to medium fire (800W/130℃). After the timing, turn off the induction cooker, move the pressure cooker away from the heat source stably, and cool naturally for 5 minutes;

(3) Move the pressure cooker stably to the sink, turn on running water to pour on the pot cover to cool it down until the automatic lock core falls into place, turn off the running water, remove the pressure limiting valve, and open the pot cover carefully (beware of steam scald). Then slowly inject running water into the pot (avoid direct flushing of tissue sections with running water);

(4) When the temperature drops below 40℃ (the water temperature is not hot to the touch), take out the slide rack and immerse it in distilled water quickly (avoid drying of sections), rinse gently with distilled water for 3 minutes × 2 times, and soak in distilled water for blocking after rinsing.

(Note: Tissue sections are prone to drying after retrieval. In subsequent operations, attention should be paid to preventing the tissues from drying when "shaking off excess liquid from tissue sections", otherwise the staining effect will be affected.)

C. Blocking of Endogenous Peroxidase

(1) Shake off excess liquid from tissue sections, place the slides in peroxidase blocker (3% H2O2) and soak for 10 minutes;

(2) After blocking, rinse gently with distilled water for 3 minutes × 2 times, and soak in distilled water for circle drawing after rinsing.

D. Circle Drawing

Shake off or carefully wipe off excess liquid around the tissue sections, draw a circle around the tissue with an immunohistochemical oil pen at a distance of 2~3mm from the tissue edge. After ensuring the entire circle encloses all the tissue, rinse gently with distilled water for 3 minutes × 2 times to wash off excess oil, and soak in PBS buffer for primary antibody incubation.

E. Adding Primary Antibody or Control Reagent

(1) Shake off excess liquid from tissue sections, add the primary antibody working solution to completely cover the tissue after the circle drawn by the oil pen is fully visible, and incubate at room temperature in a wet box for 30 minutes;

(2) After primary antibody incubation, rinse with PBS buffer for 2~3 times, then transfer to a PBS jar and soak for 2 minutes × 3 times.

(Note: During the experiment, do not rinse the tissue surface directly with PBS buffer when rinsing tissue sections, otherwise section detachment may occur.)

F. Adding HRP-Labeled Secondary Antibody Polymer

(1) Shake off excess liquid from tissue sections, add the one-step secondary antibody reagent to completely cover the tissue after the circle drawn by the oil pen is fully visible, and incubate at room temperature in a wet box for 20 minutes;

(2) After secondary antibody incubation, rinse with PBS buffer for 2~3 times, then transfer to a PBS jar and soak for 2 minutes × 3 times.

G. Adding DAB Chromogenic Solution

(1) Shake off excess liquid from tissue sections, add freshly prepared DAB chromogenic solution to completely cover the tissue, and incubate at room temperature in a wet box for 5 minutes;

(2) After DAB incubation, shake off the DAB on the slides onto absorbent paper, then put the slides into distilled water and rinse thoroughly for 3 minutes × 2 times to terminate staining.

H. Counterstaining and Bluing

(1) After thorough rinsing with distilled water, immerse in hematoxylin staining solution for counterstaining for 8~10 seconds, and rinse clean with distilled water after counterstaining;

(2) After counterstaining, immerse in 1% lithium carbonate solution for bluing for 8~15 seconds, and rinse clean with distilled water after bluing.

(Note: Adjust the counterstaining time according to the intensity of different hematoxylin staining solutions, with the cell nucleus showing light to dark blue as appropriate. Over-staining or insufficient staining may affect the judgment of results.)

I. Dehydration, Clearing and Mounting

(1) Shake off excess liquid from tissue sections, immerse the tissue sections in 85% ethanol, 95% ethanol and anhydrous ethanol successively for 3 minutes each;

(2) After dehydration, immerse the tissue sections in fresh xylene for 5~10 minutes;

(3) Mount the tissue sections with neutral gum and coverslips when they become transparent.

5) Result Interpretation:

Immunohistochemical staining results should be observed and interpreted by experienced professionals under an optical microscope.

【Quality Control】

Before interpreting the staining results of the tested specimens, the staining results of a series of quality controls such as reagent controls and tissue controls should be analyzed and confirmed, compared with known positive and negative results, and referenced to previous quality control staining results. The staining results of the tested specimens are considered valid only when a series of controls show consistent staining results with the known ones. A complete immunohistochemical experiment should include positive tissue control, negative tissue control and blank (or negative) reagent control to ensure the entire experimental process is accurate and controllable.

Positive Tissue Control should be fresh biopsy or surgical specimens, fixed, pretreated and made into paraffin-embedded sections by the same method as the tested specimens. An ideal positive tissue control should be known to contain both high and low expression of the detected antigen to ensure that the experimental results can reflect different antigen expression levels in different tested specimens, especially to avoid missing cases with low expression. Normal staining results of the positive tissue control indicate that the tissue preparation of the tested specimens is correct and the staining method is appropriate. A positive tissue control should be set up for each staining experiment. If the positive tissue control fails to show the correct positive staining, the staining results of the tested specimens in this experiment should be considered invalid. (Note: Normal staining results of the positive tissue control only indicate that the experimental procedure and reagent performance meet the requirements, and cannot be used as an evaluation standard for the specificity of the staining results of the tested specimens.)

Negative Tissue Control should also be fixed, pretreated and made into paraffin-embedded sections by the same method as the tested specimens, and known to have no expression of the detected antigen. A negative tissue control should be set up for each staining experiment to confirm the performance of the antibody and provide a background for specific staining. In most cases, the tissue sections of the tested specimens contain different cell types, and those negative cells can be used as internal negative tissue controls. If the negative tissue control shows specific positive staining, the staining results of the tested specimens in this experiment should be considered invalid.

Blank (or Negative) Reagent Control can be performed by replacing the primary antibody with PBS buffer or IgG homologous to the primary antibody. The purpose is to evaluate the specific staining of the primary antibody, judge the presence of non-specific staining, and provide a better explanation for the specific staining at the antigen site. The incubation time and temperature of the blank (or negative) control reagent should be consistent with those of the primary antibody.

【Interpretation of Staining Results】

Immunohistochemical staining results should be observed and interpreted by experienced professionals under an optical microscope.

A. Immunohistochemical staining results should be based on normal staining results of a series of controls, otherwise the staining results of this experiment should be considered invalid.

B. Positive staining result (+): On the basis of normal staining results of a series of controls, brown-yellow staining is seen at the specific sites of specific cells in the tested tissue sections without background staining, indicating the presence of the detected antigen.

C. Negative staining result (-): On the basis of normal staining results of a series of controls, no brown-yellow staining is seen in specific cells in the tested tissue sections, indicating no expression or extremely low expression of the detected antigen.

【Limitations of the Staining Method】

1) Changes in specimen fixation and pretreatment, tissue antigen retrieval, antibody incubation temperature and time, or other experimental conditions may affect the accuracy of staining results.

2) A blank (or negative) reagent control, positive tissue control and negative tissue control should be set up in each staining process, and all control staining results should be normal; otherwise, the experiment should be considered invalid.

3) A complete immunohistochemical experiment process includes multiple steps, including reagent selection, tissue selection, fixation and treatment, section preparation, staining and result interpretation. The treatment method of tissues before staining can directly affect the staining effect. Improper fixation, freezing, thawing, washing, drying, sectioning or contamination by other tissues or liquids may cause false positive, inaccurate antibody localization or false negative results. Different fixation and embedding methods or irregularities within the tissue may also cause abnormal staining results. At the same time, excessive or insufficient counterstaining may also affect the correct interpretation of results.

4) Interpretation of immunohistochemical staining results should be combined with pathological morphology and other data. Any interpretation of staining or its absence should be supplemented by morphology, correct controls and other tests.

5) The reagent may have unintended reactions in untested tissues. Due to the biological variability of antigen expression in tumor or other pathological tissues, the possibility of unintended reactions in the detected tissues cannot be completely eliminated.

6) False positive results may be caused by non-immunological binding of protein or substrate reaction products. They may also be caused by red blood cells and cytochrome C.

【Precautions】

1) This product is for research use only, not for other purposes.

2) This product must be used by professionals.

3) This product contains materials of biological origin, and its handling should comply with relevant requirements.

4) Appropriate protective measures should be taken to avoid contact of the reagent with skin and eyes.

5) The suitability of this product for non-formalin fixed tissues has not been confirmed.

6) This product contains sodium azide as a preservative, which can react with lead and copper to form explosive metal azides. To prevent the formation of metal azides, flush with a large amount of water to avoid accumulation.

【References】

[1] Li J, Wei LX. Significance of immune markers in the diagnosis and differential diagnosis of hepatic epithelial tumors. Chinese Journal of Pathology, 2014, 43(4):246-250.

[2] Gu CY, Xiao F, Qian Z, et al. Application of combined detection of Arginase-1 and Glypican-3 in the differential diagnosis of hepatocellular carcinoma. Chinese Journal of Digestion, 2014, 34(5):321-324.

[3] Wu BQ, Liu YF. Immunohistochemical Pathological Diagnosis [M]. Beijing: Beijing Science and Technology Press, 2007.

【Manufacturer】

Guangzhou Myabtech Biological Inc.

Myabtech Biological Inc.