Figure 4.

Identification of pulmonary macrophage subpopulations. (A) Subpopulation identification in interstitial (top row) and alveolar (bottom row) compartments on Day 0 was based on the following gating strategy: cells were selected according to their larger size (forward scatter [FSC]) and granularity (side scatter [SSC]) (left), on their CD45 expression to select leukocytes (middle), and on their granulocyte differentiation antigen 1 (GR-1)^high exclusion to remove neutrophils (right). (B) Macrophages were grouped into three populations based on CD11b and CD45 staining intensity. Shown are representative dot plots from Days 0, 1, 4, and 7 after infection with P. aeruginosa, identifying Group I as CD11b^lowCD45^high, Group II as CD11b^intCD45^int, and Group III as CD11b^highCD45^high. (C) Representative cytospins of cells were sorted from Groups I–III, fixed, and stained with Diff-Quik. Cells demonstrated the appearance of macrophages, and Group III was comprised of cells with more of a kidney-shaped nucleus. APC-Cy7, allophycocyanin cyanine dye.