Figure 4. Lyve-1⁺ macrophages exhibit low turnover and self-renewal in the mammary gland.

(A) Schematic of shielded bone marrow chimera experiment. (B) Representative flow cytometry plots showing the gating and identification of host (CD45.2) and donor (CD45.1) cells in the blood and mammary gland. Quantification of flow cytometry demonstrates that although most of the monocytes in the blood are donor-derived, the majority of macrophages in the mammary gland are host-derived. Cells were first gated on Live and pan-CD45 expression. In the quantification graphs, n = 23 mice from three separate experiments. (C) Quantification of flow cytometry demonstrates that the majority of Lyve-1⁺ macrophages remain host-derived 6 weeks after bone marrow transplant. (D) Mammary glands were isolated from mice after a 2 hr BrdU pulse and immunostained for BrdU and Lyve-1 (n = 3, three images/localization). Examples of BrdU⁺Lyve-1⁺ cells are shown, insets show higher magnification.