Microglia - insights into immune system structure, function, and reactivity in the central nervous system.

Microglia are essential cellular components of a well-functioning central nervous system (CNS). The development and establishment of the microglial population differs from the other major cell populations in the CNS i.e. neurons and macroglia (astrocytes and oligodendrocytes). This different ontogeny gives microglia unique properties. In recent years detailed studies of the microglial population have been greatly facilitated by the use of bone marrow (BM) chimeric animals. Experimental BM transplants have provided the opportunity to trace and investigate how BM cells migrate into the CNS and settle to become microglia. Furthermore various functional properties of microglia in the normal and pathological CNS are now being revealed because of combinations of BM transplantations and experimental disease models. Here, we describe some of the latest findings in microglial biology and discuss the potential for using microglia in therapeutic interventions.