Detection of Mycoplasma ovipneumoniae and Pasteurella haemolytica antigens by an immunoperoxidase technique in pneumonic ovine lungs.

Four hundred twenty pneumonic lungs from lambs were examined for Mycoplasma ovipneumoniae and Pasteurella haemolytica by an immunoperoxidase technique using an extravidin-biotin-peroxidase complex method in formalin-fixed, paraffin-embedded sections. Histologic examination of tissue sections revealed strong positive reactions in 60.9% and 68.3% of the lungs against M. ovipneumoniae and P. haemolytica, respectively. M. ovipneumoniae and P. haemolytica antigens were observed at the surface and/or within the epithelial cells, macrophages, leucocytes, and bronchiolar exudate. The location of M. ovipneumoniae in the cytoplasm of the epithelial cells and P. haemolytica in the neutrophils was detected immunohistochemically.