I hope someone out there in histoland can help me with this...We have been
trying to get a new antibody on line in our lab and each time we try,there is a
very distinct pattern of staining on the negative control.  The tissue being
used is a pancreas and the antibody is Tradd which is a rabbit polyclonal.
Somebody thought that  the cells staining were plasma cells(they do have
eccentric nuclei and a relatively large amount of cytoplasm) so I tried using
biotinylated F(ab')2 fragments in place of the Dako biotinylated universal
secondary.  The amount and intensity of the staining on the negative control
seems to have decreased somewhat but it is still there enough to cause problems
in reading the rest of the staining pattern.  Should I try using Fc fragments to
block the Fc receptors on the plasma cells as an extra blocking step or is this
worthless?  I don't think avidin-biotin blocking will help but I am willing to
try anything at this point.
Any help would as usual be greatly appreciated.

Sincerely,
Christine Klein
MD Anderson Cancer Center
Houston, Tx.