GPR183 promotes repopulation of lung macrophage niches by monocytes. (A and B) Chimerism of Gpr183^+/+ and Gpr183^−/− blood monocytes, lung monocytes, and alveolar macrophages from SPAM deleter mice 7 wk after bone marrow reconstitution and 4 wk after depletion of alveolar macrophages with 1 ng intratracheal DT. Data are represented as mean ± SEM. ns, not significant; *P < 0.05 by unpaired Student’s t test. Data are pooled from two independent bone marrow chimera experiments with a total of n = 6 mice per genotype. (C and D) Chimerism of Gpr183^+/+ and Gpr183^−/− blood monocytes, lung monocytes, and interstitial macrophages in the lung of IM-DTR deleter mice 4 wk after bone marrow reconstitution and 2 wk after depletion of interstitial macrophages with 50 ng intraperitoneal DT. Data are represented as mean ± SEM. ns, not significant; **P < 0.01; ***P < 0.001; by unpaired Student’s t test. Data are pooled from two independent bone marrow chimera experiments with a total of n = 6 mice per genotype. Panels A and C were adapted from Servier Medical Art. IM, interstitial macrophage.