ASTROCYTES AS MEDIATORS OF IMMUNE AND INFLAMMATORY RESPONSES IN THE CNS

The long-standing view that the brain is isolated from the effects of the immune system has recently been challenged, with experimental evid ence suggesting that in response to invasion by microorganisms, the CN S can mount its own defense by resident cells, such as the microglia a nd astrocytes. Both cell types produce and secrete a number of cytokin es and therefore can potentially modulate and integrate the communicat ion between hematogenous cells and resident cells of the CNS. This man uscript will commence with a brief overview of astrocytic functions in the CNS, and proceed to discuss astrocytic responses that may regulat e CNS inflammation. Specifically, it will address (1) the function of astrocytes as the antigen presenting cells (APCs) of the CNS, and (2) the role afforded by astrocyte-derived cytokines, and astrocytic respo nses to cytokines secreted elsewhere, in mediating and sustaining immu ne responses. Finally, some recent experimental evidence on the possib ility that astroglial impairment by pathogens may contribute to the et iology of neurologic diseases will be highlighted. (C) 1998 Intox Pres s, Inc.