Hi Dolf,
Perhaps the following story about cryostat section storage is helpful to you:
Some years ago we used to store our cryo's acetone-fixed at -20C. 
Unfortunately, it appeared that for example CD4 was lost after 2-3 months 
of storage; CD3 was lost after 4-6 months. For a while I believed that 
cryostat sections could not be stored much longer than a couple of weeks. 
Then, a rheumatology research group explained me that they store their very 
small biopsies fully cut as cryostat sections unfixed at -80C. They claimed 
to have no loss of antigens, after 1-2 years of storage.
We have successfully adopted this method for our coronary artery 
atherectomy specimens. Our oldest cyrostat sections are stored unfixed at 
-80C for a couple of years now and so far they are still working for a lot 
of antigens (CD3, CD4, CD8, CD68, T-cell activation markers, actin, etc.).

Chris van der Loos
Dept. of Cardiovascular Pathology
Academic Medical Center H0-120
Meibergdreef 9
NL-1105 AZ Amsterdam
The Netherlands

Dolf Segers wrote:
 >Date: 9 Dec 2002 03:45:12 -0600
 >From: d.segers@planet.nl
 >Subject: Storage of frozen sections
 >Dear Histonetters,
 >Just a simple question. How long can frozen unfixed sections be stored in a
 >-60 C freezer. Sections are mounted on superfrost plus slides. Does anyone
 >have experience with storage of sections, or does anyone have some advice on
 >how to optimally store our material.
 >Dolf Segers
 >Dept. Experimental Cardiology, Thoraxcenter
 >Erasmus MC, Rotterdam