I would favor using Pepsin because it does not seem to eat up the tissue/cells
as fast as the others.  Also there is a new product out on the market (still
experimenting with it myself) called Cell Prep available from American
Bio-Safety Inc, #CP-60, 1-916-652-8021, which can be  used at room
temperature.

Shirley Powell
Mercer University School of Medicine

Nima Farsinejad wrote:

>         I have noticed that most antigen retrieval protocols that were
> sent to me (and many thanks to everyone that did!) included some type of
> heat treatment. However I want to perform single cell gene array studies
> and I do not wish to heat the tissue, therefore I am thinking about using
> a proteolytic enzyme instead (Proteinase K, Pepsin, pronase, or trypsin).
> However, before I do this, I want to ask the very smart people in Histonet
> :o) about your opinion on using this enzymes and the possibility of some
> other technique that might compensate the antigen masking produced by
> formaldehyde fixation of paraffin embedded tissue.
>
> Thanks,
>
> Nima Farsinejad
> Research Specialist
> Digestive Diseases
> Emory University
> Atlanta, Georgia