1. Preheat the following to 37oC using a water bath:
(i) 200ml of TBS
(ii) 200ml of distilled water.
2. Dissolve 0.2g Trypsin 250 and 0.2g Calcium Chloride in the 200ml of TBS.
3. Once the trypsin solution is at 37oC, pH to 7.8 with 1M sodium hydroxide.
4. Place rehydrated paraffin sections in the distilled water to preheat the sections to 37oC for a minimum of 5 minutes.
5. Incubate sections in trypsin solution at 37oC. The time required will depend on the antibody and tissue, however, 30
minutes is usually sufficient.
6. Rinse sections in running tap water.
7. Proceed with immunohistochemistry protocol.
Equipment and Materials Required:
50mM Tris-buffered saline
Trypsin 250: Difco order code 0152-13 (available from Becton Dickinson).
Calcium chloride
1M Sodium Hydroxide
NB. Trypsin containing chymotrypsin should always be used. The enzyme activities can vary from a supplier and
between batches. Such Variations may affect the incubation time required.