Pulmonary clearance and phagocytic cell response in a murine model of Branhamella catarrhalis infection.

C5-sufficient Swiss-Webster mice (C5+) and C5-deficient DBA/2J mice (C5-) when challenged endotracheally with 2 x 10(7) cfu of Branhamella catarrhalis rapidly clear the lungs of viable bacteria in 48 h. This rapid clearance correlates with a striking influx of polymorphonuclear neutrophils that is of equal magnitude in both C5+ and C5- animals. Supernatant from Todd-Hewitt broth culture of B. catarrhalis exhibits in vivo chemotactic activity in the murine lung and in vitro chemotactic activity in Boyden chambers. The ability of B. catarrhalis to recruit granulocytes, independent of complement, may suggest a role for this organism in promoting protease-mediated lung destruction.