ESTABLISHMENT OF A PERMANENT RAT BRAIN-DERIVED GLIAL-CELL LINE AS A SOURCE OF PURIFIED OLIGODENDROCYTE-TYPE-2 ASTROCYTE LINEAGE CELL-POPULATIONS

A permanent glial cell line (L3) has been established from mixed glial cultures obtained from neonatal rat forebrain by repetitive passaging and selection of the process‐bearing cells growing on top of a flat cell monolayer. Continuous propagation of the process‐bearing cells was supported by the flat cells, of presumed astroglial origin, which were present in negligible amounts following each passage but then grew and formed a basal, feeder layer. Throughout a culture period of over 2 years, the L3 cells have maintained a stable morphological and antigenic phenotype. In serum‐containing culture medium, most of the process‐bearing cells expressed at the same time features of immature oligodendrocytes (O4 positivity) and of astrocytes [glial fibrillary acidic protein (GFAP) positivity]. A smaller proportion of them was labeled by the monoclonal antibody LB1. LB1 + or O4+ cells were rarely GFAP−, and GFAP+ cells were rarely LB1− or O4−. GalC+ oligodendrocytes were seen only occasionally, but the proportion of these cells increased up to 30% upon culturing in chemically defined medium containing 0.5% fetal calf serum. The L3 process‐bearing cells accumulated the neurotransmitter γ‐aminobutyric acid (GABA), expressed the proteoglycan chondroitin sulfate, and responded to the mitogenic action of platelet‐derived growth factor (PDGF) and fibroblast growth factor (FGF). All these properties are characteristic of cells belonging to the 0‐2A (oligodendrocyte‐type 2 astrocyte) cell lineage. The L3 flat cells were largely negative for the glial markers tested, but resembled type 1 astrocytes in their ability to support the growth of 0‐2A lineage cells. The L3 cell line represents a unique source of large numbers of purified 0‐2A‐like lineage cells and may therefore represent a useful experimental system to analyze the functional and developmental properties of this glial population. Copyright © 1990 Wiley‐Liss, Inc.