removing e.coli non-specific activity from antisera

[DAVID PULFORD]

Hi,  I'm looking for a rapid technique I might employ for removing
background non-specific activity from rabbit sera to E.coli proteins to
screen a fusion protein library. I've tried psuedoscreening with wildtype
bacteria on filters but have found it laborious and expensive in time and
materials.  I read a method recently that employed formalised bacteria that
was robust and quick but cannot find the reference again. Can anybody help
with ideas or a citation of this method.  Thanks.

dave p