F4/80-positive cells in neonatal tissues. Neonatal tissues (postnatal day 7) were stained for the macrophage marker, F4/80, as described in Fig 2, and counterstained with hematoxylin in liver (a and b), spleen (c and d), kidney (e and f), and lung (g and h) of +/csfm^op (a, c, e, and g) and csfm^op/csfm^op (b, d, f, and h) newborn mice born to +/csfm^op mothers. Original magnifications are ×110 (a through f) and ×230 (g and h), respectively. Bar = 50 μm.