1. Combine Trypsin concentrate with buffer in 1:3 (one part to three parts) for a working solution of 0.125% Trypsin solution.
2. Incubate the Trypsin mixture on the tissue section for 10 minutes at 37°C.
3. Rinse with cool buffer solution to stop the digestive action, and proceed with remainder of immunohistochemical protocol (i.e., application of the primary antibody).