Hi Greg,

I've done a lot of immuno for carbonic anhydrase, but it's been at the EM 
level rather than light microscopy.  But the main techniques should translate 
OK if you change the tracer system.

We used rabbit anti-human carbonic anhydrase, then biotinylated goat 
anti-rabbit IgG followed by streptavidin-colloidal gold.

This worked great on frozen and freeze-dried/embedded cells and tissues, and 
marginally well on regularly processed specimens.  A literature search 
revealed that carbonic anhydrase is water soluble and very labile to 
aldehyde-based fixatives.  

You should be OK for the first part if you're going to do regular frozen 
sections, but try to avoid prolonged floating and incubations.  The carbonic 
anhydrase (or most of it) may diffuse out of the tissue.  Maybe you could 
*very lightly* fix the sections before beginning the immunos?

Good luck!

Bob Chiovetti