We have a project that is continually giving us background problems.  At 
low dilutions of normal rabbit serum used as a control (for hyper-immune 
rabbit serum) in lung tissue from sheep and human, we have background 
staining of respiratory epithelial cells.  We have tried blocking with: 5% 
BSA, with 5% BSA with 20% normal goat serum(as that is the species of our 
secondary), with 5% BSA with 2% casein, and Biogenix powerblock.
	Does anyone have any good ways to inhibit background staining of normal 
rabbit serum in sheep and/or human lung?

Thanks!