Role of calcium chelation in high-temperature antigen retrieval at different pH values

J. M. Morgan, H. Navabi, B. Jasani

Research output: Contribution to journalArticlepeer-review

55 Citations (Scopus)


Recent work by Shi et al. on the mechanism of high-temperature antigen retrieval has claimed that the antigen retrieval process is pH-dependent, with different antigens benefitting at high or low pH values of antigen retrieval solutions. It has previously been claimed2 that chelation of Ca2+ at high temperature is an essential feature of the antigen retrieval process. In order to resolve this apparent dichotomy, the relative antigen retrieval effects were analysed using the buffers employed by Shi et al. in both a facilitating and an inhibitory mode. The results show that calcium- related effects are optimal at high pH values and do not operate at very low pH. The relative antigen retrieval effectiveness of hydrochloric acid and its metal halide solutions were also investigated in relation to pH. The results of these experiments showed that whilst HCl alone produced antigen retrieval (AR), it also produced severe tissue damage, which was reduced by the inclusion of inorganic salts. These results suggest that antigen retrieval at low pH may be achieved through the dissociation of Ca2+ complexes by high concentrations of H+ ions and/or the breaking up of cross-links from formalin fixation. Results are also presented to show that chaotropic denaturants such as urea and guanidine hydrochloride also function principally through calcium chelation, whilst detergents have no role to play in high-temperature retrieval.

Original languageEnglish
Pages (from-to)233-237
Number of pages5
JournalJournal of Pathology
Issue number2
Publication statusPublished - Jun 1 1997


  • Antigen retrieval
  • Calcium chelation
  • EDTA
  • High temperature
  • Ki-67
  • pH

ASJC Scopus subject areas

  • Pathology and Forensic Medicine

Fingerprint Dive into the research topics of 'Role of calcium chelation in high-temperature antigen retrieval at different pH values'. Together they form a unique fingerprint.

Cite this