Site-Specific Distribution of CD68-Positive Microglial Cells in the Brains of Human Midterm Fetuses: A Topographical Relationship with Growing Axons

Figure 2

Distribution of CD68-positive microglial cells in a brain at 16 weeks. Immunohistochemistry of CD68. Panel (a) displays a cortex around the optic tract. CD68-positve cells are distributed along the optic tract and around the substantia innominata (arrows). Arrowheads in Panel (a) indicate vessels containing no cells. Panel (b) exhibits a laminar distribution (sandwiched by dotted lines) of CD68-positive cells at the floor of the fourth ventricle (vent IV). Panel (c) displays the tectum and cerebellum: CD68-positive cells are distributed around a cluster of developing neurons (star) from the neuroepithelium (NEP) facing the fourth ventricle (vent IV). Panel (d) exhibits a cluster of CD68-positve cells at the superior end of the pons. Panel (e) displays a linear distribution of CD68-positve cells in the inferior olive. Insert in each panel shows the higher magnification of microglial cells.