This review explores the crucial role of border-associated macrophages (BAMs) as gatekeepers of brain homeostasis and immunity. The text details the anatomy and functions of various brain border tissues, such as the meninges and choroid plexus, where BAMs reside. It examines the distinct subsets and cell states of BAMs in both mice and humans, tracing their origins and developmental changes from embryonic stages through adulthood. Finally, the review discusses how BAMs contribute to tissue and vascular homeostasis and their essential function in brain border defense against pathogens, highlighting their involvement in both healthy brain function and neuroinflammatory diseases.

References:

• Vara-Pérez M, Movahedi K. Border-associated macrophages as gatekeepers of brain homeostasis and immunity[J]. Immunity, 2025, 58(5): 1085-1100.