Intended use: The Plus AP Kit, Mouse is based on the streptavidin-biotin system. It is designed for the qualitative detection of antigens in fixed paraffin-embedded tissue sections, in frozen tissue sections, and in cytological samples. The kit isdeveloped for use in combination with monoclonal primary antibodies and sera obtained from mice. The Plus AP Kit, Mouse can be used for examining tissues fixed in different solutions, e.g. formalin (neutrally buffered), B5, Bouin, ethanol, or HOPE.
Summary and explanation: The purpose of immunohistochemical staining is to make tissue and cell antigens visible. The Plus AP Kit, Mouse is a highly sensitive detection kit intended for use in immunohistochemistry and immunocytochemistry. The method is based on the streptavidin-biotin system which means that a biotinylated secondary antibody binds to several molecules of a conjugate composed of streptavidin and alkaline phosphatase. Visualisation occurs via an enzyme-substrate reaction in the presence of a colourising reagent which permits microscopical analysis. The biotinylated secondary antibody in the Plus AP Kit, Mouse binds to mouse primary antibodies. Therefore this kit can detect monoclonal primary antibodies and sera obtained from mice.
Reagents provided: 500 ml Blocking Solution Reagent 1 (ready-to-use)500 ml Biotinylated Secondary Antibody, Mouse Reagent 2 (ready-to-use) 500 ml Streptavidin-AP-Conjugate Reagent 3 (ready-to-use) Substrate systems recommended (if not included in the kit): Permanent AP Red Kit, BCIP/NBT Materials required but not suppliedPositive und negative control tissueXylene or suitable substitutesEthanol, distilled H2OReagents for enzyme digestion or heat pre-treatmentWash buffer PBS or TBSPAP Pen Primary antibody (user-defined)Primary antibody diluent Negative control reagentChromogenic substrateCounter stain solutionMounting mediumCover slips
Storage and handling: The solutions should be stored at 2-8°C without further dilution. Please store the reagents in a dark place and do not freeze them. Under these conditions the solutions are stable up to the expiry date indicated on the label. They should not be used after the expiry date. A positive and a negative control have to be carried out in parallel to the test material. If you observe unusual staining or other deviations from the expected results which could possibly be caused by the kit reagents, please contact our technical support
Principle of method: Paraffin-embedded tissue sections are first deparaffinised and rehydrated. Background staining caused by unspecific binding of the primary or secondary antibody is minimized by incubation with a protein blocking solution (“Blocking Solution” provided with the kit). This step can be omitted if the primary antibodies are diluted in an appropriate buffer. The next step is incubation with the specific primary antibody. After washing, the biotinylated secondary antibody is applied and incubated. This secondary antibody functions as a link between primary antibody and the streptavidinalkaline phosphatase-conjugate (“Streptavidin-AP-Conjugate“). A second washing is followed by the application of this conjugate. It binds to the biotin at the secondary antibody. Any excess of unbound streptavidin-AP-conjugate is thoroughly washed away after incubation. The addition of the chromogenic substrate starts the enzymatic reaction of the alkaline phosphatase which leads to colour precipitation where the primary antibody is bound. The colour can be observed with a light microscope. The chromogen used determines the colour. The chromogen Permanent Red (included only in kit MON-APP119) leads to a magenta-red product of reaction at the place of the target antigen. Other suitable chromogens are Permanent AP Red (magenta-red) or NBT (blue-black) with its substrate BCIP.
Reagent preparation: Reagents should be at room temperature when used. Deparaffinise and rehydrate paraffin-embedded tissue sections. Pre-treatment (optional) with HIER (Heat Induced Epitope Retrieval) or enzymatic digestion. Tissue sections have to be completely covered with the different reagents in order to avoid drying out. Preparation of the chromogenic substrate working solution (with MON-APP119 only): Add 2 drops (60 µl) of Permanent Red Concentrate to one bottle of Permanent Red Buffer (Substrate Buffer) and mix. This solution should be used directly after preparation.
Procedure: 1. Blocking Solution (protein block, Reagent 1) (This step is optional.) 5 min. 2. Washing with wash buffer 1 x 2 min. 3. Primary antibody (optimally diluted) or negative control reagent 30-60 min. 4. Washing with wash buffer 3 x 2 min. 5. Biotinylated Secondary Antibody, Mouse (Reagent 2, yellow) 10-15 min. 6. Washing with wash buffer 3 x 2 min. 7. Streptavidin-AP-Conjugate (Reagent 3, red) 10-15 min. 8. Washing with wash buffer 3 x 2 min. 9. Permanent Red substrate-chromogen solution (with MON-APP119) 5 min. 10. Wash with distilled H2O 1 min. 11. Permanent Red substrate-chromogen solution (with MON-APP119) 5 min. 12. Wash with destilled water 3 x 1 min. 13. Counterstaining and blueing 14. Mounting: aqueous or permanent after dehydration * The incubation times should be adjusted, when using other substrate-chromogen systems.
Expected results: During the reaction of the substrate with alkaline phosphatase in the presence of a chromogen, a coloured precipitate is formed at the location of the bound primary antibody. This reaction only takes place if the target antigen is existent in the tissue. The chromogen used determines the colour of the precipitate. The analysis is carried out using a light microscope.
References: Elias JM Immunohistopathology – A practical Approach to Diagnosis ASCP Press 2003/Nadji M and Morales AR Ann N.Y. Acad Sci 420:134-139, 1983