recovery in ELISA

[Patricia Werner]

Hi all,
I did express a recombinant protein in E.coli (His-tagged), purified it
and produced polyclonal antibodies in guinea pig and chicken. Next I
started doing a sandwich ELISA. My standards, that are dilutions of
recombinant protein in TBS-BSA, work nice. When I add the same amounts
of recombinant protein to my testserum, I would expect to find a
"background", that is the endogenous protein, plus the added standards.
But the recovery of recombinant protein is almost zero.
Can anybody imagine whats happening here ?

Thank you,
Patricia