Analysis of morphogenic properties of CEACAM1⁺ and CEACAM1⁻ inflammatory cells in vitro and in vivo. (A,B) Matrigel implants were retrieved on day 7, and cross-sections were analyzed for MECA-32⁺ (shown in green) and LYVE-1⁺ (shown in red) structures. In implants from B6.WT mice (A), lumenizing MECA-32⁺ and LYVE-1⁺ structures are visible (arrows), whereas implants from B6.Ceacam1^−/− mice only contain single LYVE-1⁺ cells and no MECA-32⁺ structures (B; n = 6, magnification × 630). (C-F) Matrigel tube formation assays using implant-derived cells from B6.WT (C,E) and B6.Ceacam1^−/− mice (D,F) were documented 2 days after seeding 5 × 10⁵ cells/well; magnification × 50 (C,D) and × 200 (E,F). (G) Quantification of arborizing structures from 1 representative experiment of 4. Cells from B6.WT mice are shown in ■, those from B6. Ceacam1^−/−-derived cells are shown in ○. ***P < .001. Horizontal lines indicate the mean. (H-L) Analysis of CD11b^high monocytes and their morphogenic properties after treatment with PBS- or clodronate-loaded liposomes: Dot plot histograms of CD11b^high cells in gate R3 after treatment with control liposomes (H) or clodronate-loaded liposomes (I). (J) Quantification of CD11b^high populations in peripheral blood of B6.WT mice after treatment with PBS-loaded liposomes (■) or clodronate-loaded liposomes (▵). Data shown here present the mean (± SEM) of 6 animals each, with samples analyzed on days 2, 5, and 7 during Matrigel implantation; ***P < .001. (K,L) Cross-sections of Matrigel implants retrieved from B6.WT mice undergoing treatment with PBS-loaded liposomes (K) and clodronate-loaded liposomes (L). Cross-sections were stained for LYVE-1 (shown in red) and DAPI (blue), n = 6 specimens each, magnification × 1000. (M) Quantification of LYVE-1⁺ structures in implants from B6.WT (■) or B6.Ceacam1^−/− mice (○), and B6.WT mice treated with PBS-loaded liposomes (▲) or clodronate-loaded liposomes (◇); **P < .01, *P < .05. Each symbol represents data from 1 implant. Horizontal lines indicate the mean. Experiments were performed with at least 5 animals.