An isolated expandable human neural stem or progenitor cell wherein the cell is a progenitor cells or stem cell, maintains its capability to differentiate into neurons, astrocytes, and oligodendrocytes, maintains its ability to differentiate into 5 oligodendrocyte lineage cells efficiently throughout subsequent passages, and the cell expresses at least cell surface antigens CD133 and CD140a. Also provided is a method of in vitro culturing an expandable neural progenitor or stem cell isolated from a mammalian central nervous system, and the culture itself, wherein said cell maintains its capability to differentiate into neurons, astrocytes, and oligodendrocytes 10 and its ability to differentiate into oligodendrocyte-lineage cells efficiently. In addition, a method of treating a condition caused by a loss of myelin or a loss of oligodendrocytes is provided as is a composition comprising an isolated expandable neural stem cell or one cultured by the methods of the invention. Primitive E Neural Stem Cell Adult Neural Neural Stem Cell HFSC cel StemCell z Neuronal-restricted Glial-restricted L. Precursor (NRP) Precursor (GRP) 0 Oligodendrocyte '-E progenitor cell (OPC) - Neuronal Astrocyte Oligodendrocyte Type-2 progenitor progenitor strocyte progenitor (02A) z /Pro-oligodendroblast .Neuron Type-1 Type-2 Mature astrocyte astrocyte oligodendrocyte Figure 1
Culture method to obtain and maintain a pure or enriched population of mammalian neural stem cells and/or neural progenitor cells that are prone to differentiate into oligodendrocyte-lineage cells in vitro