One form of the present invention is directed to a method of remyelinating demyelinated axons by treating the demyelinated axons with oligodendrocyte progenitor cells under conditions which permit remyelination of the axons. Another aspect of the present invention relates to a method of treating a subject having a condition mediated by a loss of myelin or a loss of oligodendrocytes by administering to the subject oligodendrocyte progenitor cells under conditions effective to treat the condition mediated by a loss of myelin or a loss of oligodendrocytes. A further aspect of the present invention relates to an in vitro method of identifying and separating oligodendrocyte progenitor cells from a mixed population containing other mammalian brain or spinal cord cell types.
