Antigen unmasking

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With antigen retrieval , epitope unmasking or antigen retrieval is in the biochemistry and immunohistochemistry the procedure referred to with which the lost immunoreactivity of formalin-fixed and paraffin-embedded tissue ( FFPE ) can be partially restored. Combinations of enzymatic digestion in so-called retrieval solutions with steam heat or microwave ovens are used. It is a method for restoration of antigens .

By fixing tissue and cells, the proteins are cross-linked with one another and sometimes also modified. Some epitopes are then no longer recognized by their associated antibody. The “antigenicity” of the protein is partially or completely destroyed by the fixation process . The cross-links (masking) can be partially reversed by the antigen unmasking. For immunostaining , the paraffin in FFPE tissues is extracted with xylene . With a descending alcoholic series , the tissue is hydrophilized with several solutions of descending concentrations of ethanol in xylene , so that the immunostaining can then take place with aqueous solutions. When extracting proteins, FFPE tissues are usually heated to 100 ° C before extraction.

history

Antigen unmasking for the use of FFPE tissues in immunostaining was first carried out in 1991 using metal ion solutions and heating with microwaves to 100 ° C.

literature

  • M. Werner, A. Chott, A. Fabiano, H. Battifora: Effect of formalin tissue fixation and processing on immunohistochemistry. In: Am J Surg Pathol . 24 (7), 2000 Jul, pp. 1016-1019.

Individual evidence

  1. ^ Gudrun Lang: Histotechnology. Springer-Verlag, 2013, ISBN 978-3-7091-1190-1 , Chapter 8.3.2.3 Reagents.
  2. ^ SR Shi, Y. Shi, CR Taylor: Antigen retrieval immunohistochemistry: review and future prospects in research and diagnosis over two decades. In: The journal of histochemistry and cytochemistry: official journal of the Histochemistry Society. Volume 59, number 1, January 2011, ISSN  1551-5044 , pp. 13-32, doi: 10.1369 / jhc.2010.957191 , PMID 21339172 , PMC 3201121 (free full text).
  3. ↑ SR Shi, ME Key, KL Kalra: Antigen retrieval in formalin-fixed, paraffin-embedded tissues: an enhancement method for immunohistochemical staining based on microwave oven heating of tissue sections. In: The journal of histochemistry and cytochemistry: official journal of the Histochemistry Society. Volume 39, Number 6, June 1991, ISSN  0022-1554 , pp. 741-748. PMID 1709656 .