Fig. 1: Generation and characterization of the CD68-rtTA mouse line.

a Schematic diagram showing the knock-in strategy of the CD68-rtTA line by homologous recombination. b Genetic lineage tracing strategy by Cre-loxP recombination in CD68⁺ cells after doxycycline (Dox) treatment. c Schematic showing the experimental design. d Flow cytometric and quantification analyses of the percentage of tdT⁺ cells among CD45⁺F4/80⁺ macrophages (efficiency) and the percentage of SiglecF⁺ alveolar macrophages (AMs, left) and CD11b⁺ interstitial macrophages (IMs, right) among tdT⁺ macrophages from the lungs. Data are presented as the mean ± SEM; n = 5 mice per group. e Flow cytometric and quantification analyses of the percentage of tdT⁺ cells expressing F4/80 (specificity) in the lungs. Data are presented as the mean ± SEM; n = 5 mice per group. f Flow cytometric and quantification analyses of the percentage of CD45⁺ monocytes expressing tdT from blood. Data are presented as the mean ± SEM; n = 5 mice per group. g Immunostaining for F4/80, tdT, and SiglecF in lung tissue sections. The boxed region is magnified. Yellow arrowheads indicate labeled macrophages. h Quantitative analysis of the percentage of tdT⁺ cells among F4/80⁺ macrophages (efficiency), the percentage of F4/80⁺ cells among tdT⁺ cells (specificity), and the percentage of AMs and IMs among labeled tdT⁺ macrophages from images of immunostained lung sections. Data are presented as the mean ± SEM; n = 5 mice per group. i Cartoon image showing the effective labeling of tissue-resident macrophages (TRMs) in CD68-rtTA;TetO-Cre;R26-tdT mice. Scale bars, 100 µm. Each image is representative of five individual samples.