Cytokeratin filament expression during in vitro teratocarcinoma cell differentiation as detected by a monoclonal antibody.

Undifferentiated F9 teratocarcinoma cells were induced to differentiate in culture using retinoic acid and cAMP. As a result, the morphology of the cultures changes dramatically. Using a monoclonal antibody directed against cytokeratin polypeptide 18 (RGE 53) in the indirect immunofluorescence technique we could show that this cytokeratin subunit is synthesized and assembled into a filamentous network upon differentiation in about 50% of the cells. Immunoblotting studies confirm these results.