In vitro analysis of the oligodendrocyte lineage in mice during demyelination and remyelination

After widespread CNS demyelination, surviving oligodendrocytes at the periphery of lesions do not seem to be able to elaborate myelinating processes and/or relocate to achieve efficient remyelination. Proliferation of oligodendrocytes, or oligodendrocTte precursor cells, during demyelination appears to be necessary to facilitate remyelination. Electron microscopic autoradiographic analyses of demyelinating tissue have reported mitosis of oligodendrocytes at several stages of maturation (Herndon et al., 1977; Ludwin, 1979; Aranella and Herndon, 1984; Ludwin and Bakker, 1988) . A recent in vivo analysis combining immunolabeling with autoradiography has shown that O-2A progenitor cells and astrocytes that express 04 antigens proliferate early in the course of demyelination induced by coronavirus infection and that some cells generated during demyelination later became oligodendrocytes (Godfraind et al., 1989) . In the present study, we have developed an in vitro system to further characterize the cells involved in the remyelination process. We have used threecolor immunofluorescence combined with autoradiography to identify specific glial cell types. In such a system we can analyze the proliferative capacity, phenotypic plasticity, and differentiation potential of the various types of glial cells which may play a key role in CNS remyelination.