Measuring Innate Immune Function in Mouse Mononuclear Phagocytes

While serving as a conduit for gas exchange, the lung continually encounters potentially harmful airborne and bloodborne substances including particulate matter, allergens, toxins, and infectious agents. Resident alveolar and interstitial macrophages coordinate with neutrophils, dendritic cells, and recruited blood-derived monocytes to provide phagocytic host defense that aids in the removal and destruction of antigenic material following this myriad of exposures. Here we describe flow cytometric methods for specifically assessing phagocytic activity ex vivo in isolated mouse lung macrophages and monocytes utilizing fluorescently labeled Streptococcus pneumoniae.