[mephamah]

Hello,

I have been trying to perform immunocytochemistry on a sample of two cell types mixed together. One group expresses cytokeratin while the other expresses CD45.  When I stain with fluorophore-conjugated monoclonal antibodies, I can stain the populations clearly (one is stained by the anti CK antibody, one is stained with the anti-CD45 antibody).  However, when I try to do the same with polyclonal antibodies, I either get no staining at all or the antibody sticks to both cells types.  I have tried 5 or 6 different sets of polyclonal antibodies, all with the same results.  Any suggestions?