re: antigen retrieval (with what?)

From:"J. A. Kiernan" <jkiernan@uwo.ca>

On Mon, 9 Jul 2001 Schmang155@aol.com wrote:
> We use Trilogy for antigen retrieval ...
> ... Trilogy is expensive though and it would be nice 
> to conserve solution if we could.

why not try to find out what's in it (almost certainly
cheap chemicals in low concentration) and then make
your own solution? The MSDS sheet should list the
ingredients but it may not give the amounts, and
some MSDS sheets quite blatantly say "TRADE SECRET"
for active components. If the maker of the solution
you like says his recipe is a secret, try one of the
dozens of published solutions. 

None are difficult to make up. For the most part they 
are water, usually buffered to a mildly alkaline pH 
(but often near neutral, and there are a few antigens 
that respond better to acidity). Something to complex 
metal ions is frequently included, such as citrate or 
EDTA. Urea (first used cold back in 1982) is another 
additive that may help in heated solutions. For 
many antigens hot water alone is OK. For some, the
older cold techniques (proteolytic enzymes, detergents)
have been shown to be better than heating in buffered
water.

There is a lot of literature in this field: far too 
many refs (even in my small collection) to put in an 
email, but two notable papers, by completely different 
groups of investigators, are worth mentioning. They 
compared retrieval solutions for several antigens of
importance in clinical pathology. 

Taylor, CR et 4 al. 1996 Biotechnic & Histochemistry 
  71: 263-270.
Pileri, SA et 15 al. 1997. Journal of Pathology
  183: 116-123. 

Look them up if you have access to a library.

If you can't do this, ask Histonetters for their
favourite in-house antigen retrieval solutions. 
You'll get many replies. Ask for the sources too,
because a peer-reviewed published procedure is
generally better than someone's anecdotal account. 

It should not be necessary for anyone to buy an 
expensive pre-made solution. I don't know the 
marketplace in this field, but surely there must 
be people selling inexpensive published antigen 
retrieval solutions with declared compositions. 

Peer-reviewed publications in the best journals 
make it quite clear that there is no single 
formulation that will unmask all the antigens in 
a section, but there are plenty of mixtures that 
do a good job for many antigens. 

----------------------------------------
John A. Kiernan
Department of Anatomy & Cell Biology
The University of Western Ontario
London,  Canada   N6A 5C1
   kiernan@uwo.ca
   http://publish.uwo.ca/~jkiernan
 
 





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