Extended Data Fig. 4: Intra-epithelial macrophages are abundant within the mammary epithelium throughout postnatal development.
From: Tissue-resident ductal macrophages survey the mammary epithelium and facilitate tissue remodelling
a, Optical sections of mammary ducts at 9 weeks of age, immunostained for K5 (magenta), MHCII (yellow) and GFP, YFP or CD11b (cyan) in WT or indicated reporter mice. Arrows indicate intra-epithelial MØs. Hollow arrowhead indicates a CD11b+ stromal cell. Images representative of 3 mice (Csf1r, CD11c and CD11b) and 6 mice (Cx3cr1). Scale bars, 20 μm. b, 3D image of a mammary gland at 2 weeks of age, immunostained for K5 (magenta) and MHCII (yellow). Enlargement: inner duct surface with opaque signal. Image representative of 3 mice. Scale bars, 200 µm (overview) and 20 µm (enlargement). c, 3D image of terminal end buds (TEBs) at 5 weeks and enlarged optical section, immunostained for GFP (cyan) and K5 (magenta) and labelled for F-actin (yellow). Image representative of 3 mice. Arrows indicate dendritic-shaped Cx3cr1hi cells within the TEB. Scale bars, 100 µm (overview) and 40 µm (enlargement). d, 3D images of ducts of the nipple, mid and distal regions of glands and enlarged optical sections, from a Cx3cr1GFP/+ mouse at 8 weeks, immunostained for K5 (magenta), GFP (cyan) and keratin 8 (K8, yellow). Images representative of 2 mice. Arrows indicate Cx3cr1hi DMs between the K8+ luminal and K5+ basal layers. Scale bars, 50 µm.
