Application of the avidin-biotin-peroxidase complex (ABC) technique for detecting avian reovirus in chickens.

An immunoperoxidase technique, avidin-biotin-peroxidase complex (ABC), was used for detecting avian reovirus in glutaraldehyde-formalin-fixed, paraffin-embedded tissues. A peroxidase-positive reaction, characterized by the presence of dark brown granules in the cytoplasm of affected cells, was found in the liver (Kupffer cells, macrophages, and hepatocytes) and bursa of Fabricius (epithelial cells, stromal cells, and/or macrophages). The early presence of peroxidase activity in the bursa of Fabricius supports our previous idea that the bursa of Fabricius may serve as a primary site of replication for natural reovirus infection.