Gr1 Cells Dominate the Early Phagocyte Response to Mycobacterial Lung Infection in Mice.

Lung infection by is characterized by chronic infection of lung-resident macrophages, long considered to be the primary hosts and determinants of the outcome of the early immune response. Although alveolar macrophages are well-known to host intracellular mycobacteria at later stages of disease, little is known about the earliest events of the innate immune response. The phagocytes that take up mycobacteria immediately following infection, and how the early lung phagocyte response is altered by vaccination with bacille Calmette-Guérin (BCG) were unknown.