Summary Clearance of non-typeable Haemophilus in¯uenzae (NTHi) from the respiratory tract was investigated, over time, in immune and non-immune rats. A triphasic pattern characterized the clearance of bacteria from the lungs. Mucosal immunization enhanced bacterial clearance from the lungs in each of the three phases compared with clearance from non-immunized animals. Total clearance of bacteria was observed from lung tissue by 12 h in immune animals and 24 h in non-immune animals. Polymorphonuclear leucocytes not only arrived earlier and initially in greater numbers, but disappeared earlier in immune animals (peaking at 8 h postchallenge), compared with non-immune animals (peaking at 12 h post-challenge). Systemically derived and locally produced NTHi-speci®c IgA and IgG correlated with enhanced bacterial clearance during the secondary phase. This model demonstrates that immunized animals up-regulate and resolve in¯ammatory responses to pulmonary infection more rapidly than the non-immunized controls.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.