We have been trying to stain for PSA-NCAM in free-floating 30 micron coronal mouse brain sections, but have had trouble getting any results. Our antibody is the 2-2b clone from EMD Millipore. So far, we have tried several dilutions (1:2000, 1:1000, 1:500, and 1:100), have tried using Fab fragments (Jackson), are using a biotinylated anti-mouse secondary (Jackson), and use DAB as the chromogen. Staining of dendritic projections in hippocampus between + and - primary is too similar to distinguish (we are looking to eventually colocalize with doublecortin). Any ideas on protocols specific for this antibody would be greatly appreciated!