Thanks Gayle,
               We are using peroxidase so  I,m glad you told me that it can
,t be quenched before I rush off and try the Zinc-Tris but thanks to
pharmingen
for suggesting it.She the student did another run over the weekend and even
tissue which was positive last time didn,t react so I think  the problem
lies in the freezing of the antibody or her procedure and solutions. Cheers
..Jill....