Hi,
    I am a firm believer that everything depends upon the proper processing
of the tissue for optimal results. Fixation is the key to the whole thing,
thats why we target retrieve the antigens. My best advise is to try to titer
out your antibodies until they just about disappear completely, then increase
your incubation time to compensate. Haste makes waste.
Amos Brooks

Peter Poon wrote:

> Can backround in IHC be caused by poor fixation or any other part of the
> tissue processing? I'm using an ABC kit to stain mouse brain tissue. When
> I omit primary antibody, my section is completely blank. I've tried three
> different rabbit polyclonal antibodies and I've blocked with peroxide,
> goat and rabbit serum. In every case the backround is unchanged. When I
> decrease primary concentration, the backround and signal decreases.
>
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