Do you do the following controls?
(Ctrl 1: no prim antibody but everything else is there.
Ctrl 2: no prim ab, no sec antibody but streptavidin conj and substrate is
used.
Ctrl 3:  no prim ab, no sec ab, no streptavidin conjugate, only substrate is
applied to the section)
Based on these controls you can figure out what may be causing the background.

I have summarized the possible  results below
("1" means background staining, "0" means none)
Ctrl1: Ctrl2: Ctrl3 = interpretation
1:1:1 = staining is possibly due to endogenous enzymes
1:1:0 = staining is possibly due to endogenous biotin
1:0:0 = staining is possibly due to the sec antibody binding to endogenous
immunoglobulins
hope this pseudo-computer language makes some sense 8^}
Good luck
Abizar
www.innogenex.com
1-877-IGX-INFO


"Philopena, Jennifer" wrote:

> Hi to all.  I am having a very very difficult time getting clean results
> from IHC on nude mouse tissue (livers particularly).  I have background on
> tissues using both fluorescence (no avidin or biotin - staining is light)
> and chromogen, with both antibodies (polyclonal anti-E1a and ctrl.) from
> Sant-Cruz.  Thanks for all your input.
>
> Jennifer M. Philopena
> Scientist 1
> Canji, Inc.
> 3525 John Hopkins Court
> San Diego, CA 92121
> jennifer.philopena@canji.com