[Histonet] Granzyme B and F4/80 immunostaining

[Jennifer Campbell]

Hi All,
 
  I'm currently trying to work up Granzyme B and F4/80 on FFPE mouse tissue.  I seemed to get a bit of non-specific staining for both and was wondering if there is any way I can eliminate some of this.  For Granzyme B I am using a rabbit polyclonal from Abcam.  My protocol goes like this: H202 block, citrate buffer HIER, Powerblock (casein-based, non-serum protein block), primary antibody, secondary antibody (rabbit-on rodent HRP polymer, from biocare), DAB, counterstain.  My F4/80 is a rat anti-mouse primary from Serotec and the protocol is as follows: H202 block, citrate buffer HIER, Powerblock, avidin/biotin blocks, primary antibody, secondary antibody (Goat anti-rat, biotinylated, mouse-absorbed, from Biocare), HRP Label, DAB, counterstain.  Is it true that if I switched to a serum block from the species in which the secondary was raised, instead of my non-serum protein block, it may help?  Thank you in advance!
 
Jennifer