Dear Colleagues: We would very much appreciate suggestions on a technical
problem involving polyclonal Abs. We have a polyclonal serum from a rabbit
immunized against recombinant newt FGF-1. In trying to determine
immunoreactivity in tissues such as brain, kidney, and blastema, we cannot
see reactivity over and above that of pre-immune serum (the control). Thus
both Anti serum and pre-immune give the same immunoreactivity, each of which
appears to be non-specific. We have tried a range of anti-serum
concentrations, blocking agents (non-fat dry mild and/or bovine serum), etc.
to no avail. We know the anti-serum is specific because on dot blots and
Western blots the anti-serum gives signal but the pre-immune serum does
not. Thus the non-specific reactivity is to tissues. We have also tried
different fixations and times of fixations. Does anyone have suggestions?