I haven't done a lot of work with fluorescence IHC, but we now need to do
some CD31 staining and use either an Alexa Fluor 594 or Texas Red conjugated
secondary antibody for detection. We get very nice CD31 staining, but we
also get rather strong staining of RBCs within and outside of blood vessels.
I've tried reducing the concentration of the secodaries, but the staining
still persists. Slides done with buffer control for the CD31 are clean with
the exception of the RBC staining. Both secondaries tested so far are from
Molecular Probes. I think this is a fine company and their technical
department is trying to give us assistance but so far we have not solved the
problem. This afternoon we will try a run using a secondary from another
company just to see what happens. Any suggestions for solving this problem
will be most welcome.

John E. Tarpley 5-1-A
Associate Scientist
Amgen Inc.
One Amgen Center Drive
Thousand Oaks, CA 91320