Cell Surface Changes Accompa Embryonal Carcinoma Cell Line .nying the Neural Differentiation of an

The murine embryonal carcinoma cell line P19S1801Al develops into neuronlike cells after treatment with retinoic acid (Edwards and McBurney, 1983). We have analyzed the expression of cell surface carbohydrate antigens and intracellular cytoskeletal antigens in differentiating OlAl cells in order to identify the cell types present in the cultures and to characterize the differentiation process. Undifferentiated OlAl cells express the SEA-1 antigen, GD, ganglioside, and the D1.l ganglioside antigen, carbohydrate markers that are found on early embryonic cells and neuroepithelial germinal cells in viva. The cells also bind tetanus toxin, cholera toxin, and monoclonal antibody A2B5, probes that bind to gangliosides found on the surfaces of neurons and immature astrocytes in viva and in vitro. They contain vimentin-type intermediate filament antigens but have no detectable neurofilament or glial filament protein antigens. After aggregation of the cells in medium containing retinoic acid followed by growth in a serum-free chemically defined medium, over 80% of the cells differentiate into neurons as determined by immunofluorescent labeling with antibodies against neurofilament protein antigens. The differentiated cells no longer express either the embryonic or neuroepithelial carbohydrate antigens, but they continue to express the cell surface markers characteristic of neurons. These changes in the expression of cell surface antigens are accompanied by changes in ganglioside metabolism, including a shift towards the synthesis of more complex gangliosides. Thus, the retinoic acid-induced changes in OlAl cells in vitro resemble the in viva development of neurons. This establishes the OlAl cell line as a relevant model system for studies of the molecular basis of neuronal differentiation and development.