[Histonet] very specific background immunofluorescence in mouse embryo sections

[Anna Elisse Beaudin]

Hello,

  We've been doing some immunofluorescence in mouse embryos sections
(E9-10), and have recently encountered a problem involving very specific
immunofluorescent 'staining' in our negative controls.  the staining
looks to be in specific cells in specific regions, and occurs in both
our no-primary and no-secondary controls.   we are staining with a
rabbit anti-caspase, followed by an alexafluor-conjugated donkey
anti-rabbit. the background 'staining' if very bright and can be seen
with several different filters.  has anyone else ever experienced
anything like this?  we are stumped.  I have never had this kind of
problem previously in other mouse tissues.  if anyone has any insight, I
would greatly appreciate your input.

Thanks in advance,

Anna Beaudin
Division of Nutritional Sciences
Cornell University