Flow Cytometry Reveals Similarities Between Lung Macrophages in Humans and Mice

Using these markers we also observed heterogeneity in the alveolar macrophage population, which may reflect the relative contribution of monocyte-derived versus tissue-resident cells to the alveolar macrophage pool. Because this panel relies exclusively on the identification of cell surface markers, it is appropriate for sorting and recovering live cells for subsequent analysis. CD 163 is a scavenger receptor for hemoglobin/haptoglobin complex highly expressed on tissue macrophages, and it has been proposed as a marker of "resolving" monocyte-derived macrophages (10, 11). Because our previous studies in a mouse model of lung fibrosis demonstrated that differential expression of Siglec F allows discrimination of the tissue-resident and monocyte-derived macrophages (8), we now speculate that the heterogeneity in CD 163 expression in human alveolar macrophages may also reflect their differential ontogeny.