Mitogenic effect of axolemma-enriched fraction on cultured oligodendrocytes

An in vitro system has been devised to study the mitogenic effect of axolemma on cultured oligodendrocytes. Addition of axolemma-enriched fraction to cultured oligodendrocytes results in a dose-dependent mitotic response with an 11-fold stimulation at a membrane concentration of 200 micrograms/ml. The interaction between oligodendrocytes and axolemma is specific, as myelin-enriched fraction, astrocyte membrane, and red blood cell membrane showed little or no effect on the oligodendroglial proliferation under similar conditions. In addition, cultured astrocytes were tested with the same axolemma membrane, and no mitotic stimulation was observed. The mitogenicity of AEF membrane on cultured oligodendrocytes is sensitive to heat and trypsin treatment, suggesting that the axolemma mitogen may be a protein.