Clonal permanent cell lines with astrocytic or microglial properties have been established from explant cultures of 8-day postnatal mouse cerebella after in vitro spontaneous transformation. [48963] [49701]Sister flasks of lethally irradiated astrocytes, which are known to synthesize the macrophage-microglia growth factor, M-CSF, were used as a substrate for cloning the cells. [48963] [49701]
The cell lines were derived in a multistage process. Slowly proliferating foci with several morphologies appeared 4 months after initiation of the cultures and became progressively enriched by cells with a homogeneous appearance. [48963]
Some of these cloned cell lines bound anti-glial fibrillary acidic protein （GFAP） antibodies and therefore appeared to be astrocytic. No other glial neuronal or microglial markers have been detected in these clones. [48963]
According to their morphology, 3 separate types of these GFAP-positive clones could be distinguished. Type I and II cells had small somata. [48963]
Type I had several short processes, while type II had two processes, one of which was very thin and long （greater than 200 microns）. Type III cells had large flat somata and no processes. [48963]
The astrocyte type II cloned cell line named C8-S is available as ATCC CRL-2535 and the astrocyte type III cloned cell line named C8-D30 is available as ATCC CRL-2534.
One clone with microglial properties named C8-B4 is available as ATCC CRL-2540.
The C8-D1A cell line has the morphology of fibrous astrocytes.
These astrocytic clones might be the in vitro counterparts of fibrous （type I）, or velamentous （type III） astrocytes and of Golgi epithelial cells （type II）. [48963]
