Immunohistochemistry Protocol for Formalin-Fixed, Paraffin Embedded Tissues Using Steam Based Antigen Retrieval
Tissue Sectioning, Deparaffinization, and Rehydration
- Section paraffin blocks into 4 micron sections with microtome and place on charged microscope slides (Fisher, ProbeOn, Cat. #22230900).
- Heat slides in a tissue-drying oven for 45 minutes at 60°C.
- Wash slides in 3 changes of xylene for 5 minutes each at room temperature.
- Wash slides in 3 changes of 100% alcohol for 3 minutes each at room temperature.
- Wash slides in 2 changes of 95% alcohol for 3 minutes each at room temperature.
- Wash slides in 1 change of 80% alcohol for 3 minutes at room temperature.
- Rinse slides in running distilled water for 5 minutes at room temperature.
Antigen Retrieval
- Steam slides in 0.01 M sodium citrate buffer, pH 6.0, for 20 minutes at 99-100°C.
- Remove slides from heat and hold in citrate buffer for 20 minutes at room temperature.
- Rinse slides in 1X TBS with Tween (TBST) for 1 minute at room temperature.
The following steps are to be conducted at room temperature. Do not allow tissues to dry at any time during the staining procedure.
Immunostaining with AP-Vector Red Detection System
- Apply a Universal Protein Block (Dako, Cat. #X0909) to the slides and incubate for 20 minutes.
- Drain protein block from slides.
- Apply diluted primary antibody to the slides and incubate for 45 minutes.
- Rinse slides in 1X TBST for 1 minute.
- Apply a biotinylated secondary antibody to the slides (specific to the host of the primary antibody) and incubate for 30 minutes.
- Rinse slides in 1X TBST for 1 minute.
- Apply Alkaline Phosphatase Streptavidin (Vector, Cat. #AK5000) to the slides and incubate for 30 minutes.
- Rinse slides in 1X TBST for 1 minute.
- Apply Alkaline Phosphatase Chromogen Substrate (Vector, Cat. #SK5100) to the slides and incubate for 30 minutes.
- Wash slides in distilled water for 1 minute.
Immunostaining with HRP-DAB Detection System
- Apply peroxidase block (3% hydrogen peroxide) to the slides and incubate for 5 minutes.
- Rinse slides in 1X TBST for 1 minute.
- Apply DAKO Universal Protein Block (Dako, Cat. #X0909) to the slides and incubate for 5 minutes.
- Drain protein block from the slides.
- Apply primary antibody to the slides and incubate for 45 minutes.
- Rinse slides in 1X TBST for 1 minute.
- Apply LSAB2 System-HRP LINK solution (DAKO, Cat. #K0679) to the slides and incubate for 15 minutes.
- Rinse slides in 1X TBST for 1 minute.
- Apply LSAB2 System-HRP Streptavidin-HRP solution (DAKO, Cat. #K0679) to the slides and incubate for 10 minutes.
- Rinse slides in 1X TBST for 1 minute.
- Apply prepared DAB Substrate-Chromogen solution (DAKO, Cat. #K3468) to the slides and incubate for 5 minutes.
- Rinse slides in 1X TBST for 1 minute.
Counterstaining with Hematoxylin
- Stain slides with 65% Harris' Hematoxylin for 1 minute. Hematoxylin stains nucleic acids (nuclei) a deep blue-purple.
Dehydration and Coverslipping
This method should only be used if the chromogen substrate used is alcohol insoluble (e.g. Vector Red or DAB).
- Wash slides in 2 changes of 80% alcohol for 1 minute each.
- Wash slides in 2 changes of 95% alcohol for 1 minute each.
- Wash slides in 3 changes of 100% alcohol for 1 minute each.
- Wash slides in 3 changes of xylene for 1 minute each.
- Apply coverslip with a drop of permanent mounting medium.
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