On Mon, 10 Jul 2000 kkdulany@unmc.edu wrote:

> How can you successfully perform immunohistochemistry on slides of liver
> tissue using horse-radish peroxidase and DAB?  How do you quench the
> endogenous peroxidase in the tissue so everything doesn't turn brown?  I've
> tried 3, 10 and 15 % H2O2 in both methanol and di water for 20 min. up to 1
> hour with no success.  The tissues are formalin fixed and embeded in
> paraffin.  We then used a pH 6.0 citrate buffer/microwave antigen retrieval
> system for our primary Ab detection.  Even with all that the endogenous
> enzyme caused the false positive with the DAB.  Anyone have any
> suggestions?
> Thank you for all replies.
> Karen in Omaha
> 
> 

Karen,
What antibody are you using?  Everythin you do sounds like what I do but
maybe you can skip the antigen retrieval step and see what happens.  My
guess is that omitting that will help.

Dana Settembre
Immunohistochemistry Lab
Pathology Department
University Hospital
Newark,  New Jersey
USA