OBTENTION AND CHARACTERIZATION OF PRIMARY ASTROCYTE AND MICROGLIAL CULTURES FROM ADULT MONKEY BRAINS

Simple methods for obtention of primary cultures of isolated astrocyte s and microglia from adult simian brain have been developed. Character ization of these two glial cell populations were performed by morpholo gical observations and by immunocytochemistry. The astroglial cultures were obtained by an indirect method. After L-leucine methyl-ester tre atment and trypsinizations, more than 99 % of cells expressed glial fi brillary acidic protein (CLAP), whereas no macrophages or microglia co uld be detected. Likely, the 1% remaining cells were immature astrocyt es or cells that lost their GFAP expression. Cultured simian astrocyte s expressed vimentin, laminin, and fibronectin. We also found a consti tutively low expression of major histocompatibility complex (MHC) clas s II by cultured astrocytes which was significantly enhanced by lipopo lysaccharide (LPS), interferon gamma (IFN-gamma), or tumor necrosis fa ctor alpha (TNF-alpha) treatments. Microglial cultures were obtained b y a direct method of isolation using Percoll gradient separations and compared to simian monocyte-derived macrophages or alveolar macrophage s. Microglial cells differed from macrophages by their proliferation u pon granulocyte-macrophage colony stimulating factor (GMCSF) treatment and by their typical morphology when observed by scanning electron mi croscopy. As macrophages, they expressed in vitro CD68, CD64, CD14, CD 11b, MHC class II, and fibronectin. However, contrary to macrophages, simian cultured microglia expressed laminin. This observation suggests that microglia represent a new potential source of this extracellular matrix protein in the brain. (C) 1997 Wiley-Liss, Inc.