Tracking lung macrophages with lipophilic fluorescent dyes

Pulmonary macrophages are a heterogeneous population of immune cells that patrol the lungs, ingesting particulates and microbes, and activating inflammation when necessary. During homeostasis, two main subsets of macrophages coexist: resident alveolar macrophages (AMs) and bone marrow (BM)-derived macrophages. Identifying and characterizing these subsets during lung inflammation is challenging due to altered expression of cell surface markers.