Figure 3

Macrophage distribution in mammary glands of +/Csf1 ^op control and Csf1 ^op/Csf1 ^op mice during pregnancy and lactation. F4/80 immunohistochemistry of mammary section of day 14 (P14; a-d) and day 18 (P18; e,f) of pregnancy and day 4 postpartum of lactation (PP4; g,h) from control (a,c,e,g) and Csf1 ^op/Csf1 ^op (b,d,f,h) mice. Note the abundance of F4/80⁺ macrophages tightly associated with alveoli in control mice at all stages shown, while macrophages are almost absent in Csf1 ^op/Csf1 ^op mice at all stages of mammary development. The few macrophages (filled arrowheads, d) seen in Csf1 ^op/Csf1 ^op mice are not adjacent to the alveoli, and most of the F4/80 cells seen are eosinophils (empty arrowheads, d). Original magnification: a,b,e,f,g,h: × 400; c,d: × 1000.