Dear Cynthia,

Endogenous peroxidase activity should be blocked prior to the 1st antibody
incubation. I recommend that the endogenous peroxidase activity be blocked
following deparaffinization and prior to antigen retrieval. For paraffin
embedded tissues endogenous blocking reagent can be prepared by adding 1
part of 30% hydrogen peroxide to 9 parts absolute methanol (mix well). The
tissue should be incubated in solution for 10 minutes at room temperature.

Best regards,

Aaron Levin
Zymed Laboratories
1-800-874-4494


-----Original Message-----
From: Cynthia Favara <cfavara@niaid.nih.gov>
To: 'HistoNet Server' <HistoNet@Pathology.swmed.edu>
Date: Friday, April 02, 1999 8:13 AM
Subject: IHC endogenous peroxidase block


>Netters,
> Curious as to when people block for endogenous peroxidase. Before or
>after 1st/link antibody. Has anyone done any experiments for epitope
>destruction caused by the peroxidase block?
>Thanks for the input.
>
>Cynthia Favara
>Rocky Mountain Laboratories
>903 S 4th Street
>Hamilton, MT 59840
>ph: 406-363-9317
>FAX: 406-363-9286
>e-mail: cfavara@nih.gov
>
>