Antigen Retrieval
A pre-treatment step in immunohistochemistry that unmasks epitopes in formalin-fixed tissue to restore antibody-binding capacity.
Full Definition
Formalin fixation creates methylene bridges that cross-link proteins and mask antigenic epitopes, reducing or abolishing antibody binding in IHC. Antigen retrieval (also called epitope retrieval) restores these epitopes by breaking the cross-links using heat-induced epitope retrieval (HIER)—in a buffer at defined pH—or by proteolytic enzyme digestion. The choice of retrieval method, buffer pH, and incubation conditions is antibody-dependent and must be specified precisely in laboratory protocols. Editors should note that 'antigen retrieval' and 'epitope retrieval' are used interchangeably in the literature, though 'epitope retrieval' is increasingly preferred in contemporary publications.
Usage
Usage note: 'Antigen retrieval' and 'epitope retrieval' are interchangeable; choose one and apply consistently. Always accompany with the retrieval method (HIER or enzymatic), buffer, pH, and temperature in protocols.
In Context
- "Antigen retrieval was performed using citrate buffer (pH 6.0) at 95 °C for 20 minutes prior to primary antibody incubation." — IHC laboratory protocol
- "Failure to specify the antigen retrieval method in the methods section was flagged by the editor as a reproducibility concern." — Peer-review editorial comment