Indirect immunoperoxidase and immunofluorescence staining of Bordetella bronchiseptica in formalin-fixed, paraffin-embedded lung tissues of rabbits.

Indirect immunoperoxidase (IP) and immunofluorescence (IF) techniques were developed, and used for the identification of B. bronchiseptica in formalin-fixed, paraffin-embedded lung tissues of 26 rabbits displaying focal chronic interstitial pneumonia, vascular changes, and chronic bronchitis and bronchiolitis. Labelled B. bronchiseptica organisms were observed at the level of the bronchial and bronchiolar mucosa, both in areas affected by chronic bronchitis-bronchiolitis and in zones that were free of lesions. B. bronchiseptica was not observed in areas of focal chronic interstitial pneumonia, nor in vessels exhibiting inflammatory changes. B. bronchiseptica was observed also in a few rabbits that were culturally negative for this agent. The results obtained suggest that B. bronchiseptica could have been related to the lesions of chronic bronchitis and bronchiolitis observed, but not to the changes of focal chronic interstitial pneumonia and vasculitis, as areas affected by these alterations did not exhibit B. bronchiseptica immunoreactivity.