Most fixatives immobilize the tissue antigens by forming cross linkages.
Sometimes extensive cross-linking of proteins in high concentrations can also lead to the masking or destruction of antigens, which leads to poor staining or no staining at all. This loss of staining can be restored to a certain extent by pretreatment of tissue sections with proteolytic enzymes. The unmasking of tissue sections is an important requirement for the optimal staining of antigens like immunoglobulins, keratins, carcinoembryonic antigen, factor VIII related antigen, testosterone, and to a lesser degree, S-100 protein. Product Size Catalog No. All rights reserved.