Induction of bronchial hyperresponsiveness by Bordetella bronchiseptica infection in dogs

Six beagles were examined for time-related changes of bronchial responsiveness to methacholine, plasma histamine and thromboxane B2, and biopsy of bronchial tissues after intratracheal injection of Bordetella bronchiseptica. A progressive increase in bronchial responsiveness was induced after injection. The mediators, however, did not elevate and tissue neutrophil counts did not correlate with increased airway hyperresponsiveness. Intratracheal injection of heat-killed Bordetella bronchiseptica produced no alteration in these parameters. Thus, it is speculated that airway epithelial damage and effects on ciliostatic function induced by the organism are primarily involved in the pathogenesis.