Aldehyde-Releasing Reagent for Antigen Retrieval in Fixed Tissue

The patent applies preliminary proteolytic enzyme treatment to aldehyde-fixed tissue sections before immunohistochemical staining. This preliminary action breaks down the cross-linked protein structures formed during aldehyde fixation, thereby restoring antigen accessibility without compromising the already-preserved tissue morphology. The enzyme treatment is performed as a preparatory step that reverses the harmful cross-linking effects while maintaining the structural integrity achieved during fixation.

The patent introduces proteolytic enzymes as an intermediary substance that mediates between the conflicting requirements of preserving tissue morphology and restoring antigenicity. Rather than using extreme methods like microwave heating or alcohol fixation that directly damage tissue structure, the enzyme acts as a gentle intermediary that selectively breaks down cross-linked proteins to expose antigens while leaving the overall tissue architecture intact. This intermediary approach allows simultaneous achievement of both morphological preservation and antigen retrieval.

The patent develops a universal proteolytic enzyme treatment protocol that can be applied to multiple types of tissue samples including paraffin-embedded sections, celloidin-embedded sections, and decalcified bony tissues. The method uses proteolytic enzymes that function effectively across different embedding media and tissue types without requiring modification of the basic protocol or external heat sources. This multi-functional approach allows the same enzymatic treatment to restore antigenicity in diverse fixed tissue samples, greatly expanding the applicability of antigen retrieval techniques.