Adriana,

what primary antibody are you using? what species are you working with? what
species are your reagents made in? is there staining in your sections where
you have not applied the primary antibody but applied all other reagents
(negative control)?  are the tumor cells you mentioned within the lymph
nodes?  if so, are the positive staining histiocytes close to the tumor
cells (macrophages processing the tumor antigen of interest)? i would be
interested to know your protocol for blocking for endogenous peroxidase
activity. most probably, if the staining is within your negative control
sections I would think that you might need to block with H2O2 longer.  Are
the RBCs also slightly positive?  I would suggest to try going to a
different detection system like alk phos (with levamisol treatment) and see
if you still have the same artefact.

rob


-----Original Message-----
From: Turriago, Adriana [mailto:ATURRIAGO@chromavision.com]
Sent: February 24, 2000 6:17 PM
To: histonet@pathology.swmed.edu
Subject: Sentinel Node


Hi all,

I was wandering if any of you have encountered problems with histiocytes
picking up the stain when staining with AE1/AE3.  I have run a couple of
lymph nodes and I get a granular staining with a different pattern than the
tumor cells. I am using LSAB2 as a detection system.

Any recommendations will be appreciated

Thanks,

Adriana


Adriana Turriago
Assay Development
Chromavision Medical Sytems
Phone # (949) 443-3355
Fax (949) 443-3366
e-mail: Aturriago@Chromavision.com