Characterization of neurotrophic factors produced by immortalized mouse brain glial cells (VR-2g)

We analyzed the neurotrophic factors secreted by immortalized fetal mouse brain glial cells (VR-2g). Concentrated conditioned medium of VR-2g cells were applied to a gel filtration column and the trophic activities of the fractions were determined by the bioassay method with primary fetal rat striatal neurons. Several peaks of neurotrophic activity were detected, the most prominent of which was found in a fraction of molecular weight 5-7 kDa. In peak fractions of molecular weight 13-26 kDa, molecules reactive to anti-NGF antibodies were detected by Western blotting only in non-reduced condition of SDS-PAGE. Anti-NGF antibodies absorbed 40% of the neurotrophic activities in the conditioned medium of VR-2g cells.