strange precipitate on western blot

Sheryl White slw at
Thu Oct 25 11:35:46 EST 2001

> From: Ricky Boernke <ricky_boernke at>

> we have raised this antiserum against our protein by immunizing a little
> bunny. However, when we do western blot with this serum all we see are
> millions of little spots on the membrane but no specific signal. Looks
> like
> something precipitated onto the membrane resembling kind of hot spots
> in northern blots. We checked all our reagents but it seems that this
> phenomenon only occurs with this specific antiserum. Have you ever
> observed
> something like this and how to solve this problem?
> Any input welcome.
> Best wishes
> Ricky

I have seen this before, and solved the problem by filtering the antiserum
through a 0.45 uM syringe filter.  I don't know what is causing the
particulate adhering to the blot, but others in the lab have run into the
same thing on occasion with various antibodies, some of them commercially
made.  Good luck,

Sheryl White

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