ATTEMPTS TO PRODUCE ASTROCYTE CULTURES DEVOID OF OLIGODENDROCYTE GENERATING POTENTIAL BY THE USE OF ANTIMITOTIC TREATMENT REVEAL THE PRESENCE OF QUIESCENT OLIGODENDROCYTE PRECURSORS

The presence of oligodendrocyte precursor cells which cannot be remove d from primary cultures by antibody-dependent techniques complicates t he interpretation of transplantation experiments designed to examine t he potential of astrocytes to influence remyelination (Blakemore et al .; Glia 13:79-91, 1995). In the present series of experiments we have investigated the use of the antimitotic cytosine arabinoside to elimin ate oligodendrocyte precursors from mixed glial cell cultures followin g immunolytic removal of both oligodendrocytes and oligodendrocyte pro genitors using A2B5 and O4 monoclonal antibodies. Our results indicate that not all oligodendrocyte precursors are involved during the subse quent regeneration of oligodendrocytes since a population of precursor s survive 3-day and 12-day exposure to cytosine arabinoside. Maintaini ng immunolysed cultures in serum-free medium containing cytosine arabi noside for 23 days, removed the potential to generate large clones of oligodendrocytes both in vitro and following transplantation. However, a small number of oligodendrocyte precursors survived this treatment and generated single oligodendrocytes in vitro and isolated clusters o f oligodendrocyte remyelination following transplantation. Overall, th ese results indicate that oligodendrocyte precursors have considerable potential to generate oligodendrocytes, but, since they can also sur, ive for long periods in a quiescent state, their complete elimination from immunolysed astrocyte cultures by the use of an antimitotic is u nreliable, if not impossible. (C) 1997 Wiley-Liss, Inc.