Dear Karen

Don't know whose antibody you are using, but we use Dako's. They recommend
heat mediated retrieval in citrate buffer pH 6.0, HOWEVER this was not very
successful for us. We found EDTA HCl buffer pH 8.0 in a pressure cooker gave
good staining.
As with all antibodies don't believe every thing the manufacturers say, it
may well work for them, but others may need to try something else.

Good luck

John Auld
Immunocytochemistry
Royal Free Hospital
London