Effects of Interactions BetweenPasteurella haemolyticaandBordetella parapertussisonin vitroPhagocytosis by Lung Macrophages

The aim of the work was to determine the effect of exposing ovine bronchoalveolar macrophages (BAM)in vivotoPasteurella haemolyticaand/orBordetella parapertussison the subsequent uptake and killing ofP. haemolyticaby these cellsin vitro. Exposurein vivotoP. haemolyticadid not affect the uptake ofP. haemolyticaby BAMin vitrobut reduced (P< 0·05) the intracellular killing of bacteria. Exposurein vivotoB. parapertussishad no significant effect on either the uptake of killing ofP. haemolytica in vitro. However, sequential exposurein vivotoB. parapertussisandP. haemolyticareduced both the ingestion (P< 0·05) and killing (P< 0·001) ofP. haemolytica in vitro. These results indicate that exposure toP. haemolyticacompromised the bacterial killing mechanisms of BAM and that synergy betweenB. parapertussisandP. haemolyticareduced the ability of BAM to ingest bacteria.