Hi Russ and John,
I seem to have missed the beginning of this debate, but assume it is more
about heat in processing than the effect of formalin.  If you read the paper
by Morgan et al J Pathol 1994;174:301-307, ("possible role of tissue-bound
calcium ions in citrate-mediated high temperature antigen retrieval"), they
imply that heat alone (e.g. microwaving dry) does not retrieve antigenicity.
You have to have the tissues in an ionic salt solution.  This suggests that
the buffer solution implements the major effect, whatever that is!

Phil Hall
St Michael's Hospital
BRISTOL	UK

	----------
	From:  RUSS ALLISON[SMTP:Allison@Cardiff.ac.uk]
	Sent:  05 August 1999 09:24
	To:  LOVE, JOHN E. (JSC-SD)
	Cc:  histonet@pathology.swmed.edu
	Subject:  Re: Paraffin embedding and immunocytochemistry

	John,
	Simple question you raised.  We are working on the answer - not easy

	but very interesting!
	If the heat of molten paraffin "destroys" immuno-reactivity, how
come 
	we use heat for antigen retrieval?
	Russ Allison, Wales