GRANULOCYTE-MACROPHAGE COLONY-STIMULATING FACTOR STIMULATES IN-VITRO PROLIFERATION OF ASTROCYTES DERIVED FROM SIMIAN MATURE BRAINS

In the brain, granulocyte-macrophage colony stimulating factor (GM-CSF ) may be released by infiltrated cells of the immune system including T and B lymphocytes and mononuclear phagocytes, but also by nervous sy stem resident cells such as microglia and astrocytes. Astrocyte-secret ed GM-CSF may play an important role in enhancing the local inflammato ry response to central nervous system (CNS) injury and in recruting mi croglia and activated macrophages. In this study, we demonstrated that GM-CSF, as TNF alpha and IL 6, stimulates in vitro proliferation of s imian astrocytes in primary cultures. Results were confirmed by blocki ng experiments performed with a specific neutralizing mAb directed aga inst GM-CSF. Furthermore, we demonstrated that GM-CSF mediates its eff ect on these cells through the or subunit of the GM-CSF receptor which is constitutively expressed at the membrane of the cultured simian as trocytes as assessed by immunofluorescence. GM-CSF effects on astrocyt es could be involved in astrocytosis, a hallmark of various neurologic al injuries and in inflammatory processes in an autocrine manner. (C) 1996 Wiley-Liss, Inc.