FIG 8.

Production of alveolar macrophages requires LPL. (A to D) Regeneration of alveolar macrophages is delayed when donor bone marrow is derived from LPL^−/− mice. (A) Representative flow cytometric analysis of bone marrow chimeras showing the percentages of the indicated cells derived from either donor (CD45.2⁺) or recipient (CD45.1⁺) bone marrow. Populations of neutrophils (PMNs), CD11b⁺ dendritic cells (DCs), and alveolar macrophages (AMs) were determined as described in Materials and Methods (Table 1). (B) Percentages of each indicated cell type derived from either WT or LPL^−/− donor bone marrow. (C) Numbers of alveolar macrophages isolated from BAL fluid of recipient mice that were endogenous (CD45.1⁺; recipients) or derived from donor bone marrow (CD45.2⁺). For panels B and C, data shown are means ± standard errors of the means, and P values were determined by a Mann-Whitney test (n = 5 [LPL^−/− reconstituted] or 6 [WT reconstituted], with data pooled from 2 independent experiments). (D) Percentages of neutrophils (PMNs) and alveolar macrophages derived from CD45.1⁺ WT donor bone marrow, CD45.2⁺ LPL^−/− donor bone marrow, or CD45.1⁺/CD45.2⁺ recipient cells. Data shown are means ± standard errors of the means, and P values were determined by a Mann-Whitney test (n = 9 mice, with data pooled from 2 independent experiments). (E) Percentages of alveolar macrophages positive for BrdU incorporation. (F) Mean fluorescence intensities (MFI) of annexin V-APC staining on alveolar macrophages either present in the BAL fluid or isolated from lungs. (G) Percentages of mixed progenitor cells found in bone marrow. (H) Percentages of total cells from peritoneal wash specimens that were macrophages. (I) Percentages of total cells from peritoneal wash specimens that were monocytes. For panels E to I, each symbol represents data from one mouse, lines represent median values, P values were determined by a Mann-Whitney test, and data were pooled from at least two independent experiments. n.s., not significant.