Biochemical Analysis and Cellular Location of the GCTM-2 Antigen in Embryonal Carcinoma and in Other Tumour Cell Lines

Abstract

We have previously described the development of monoclonal antibody GCTM-2 from a detergent-insoluble extract of the human embryonal carcinoma (EC) cell line GCT 27 (Pera et al. 1988). Immunofluorescence studies showed that GCTM-2 strongly stained human EC cells in preparations of cells fixed in a 50 : 50 mixture of methanol and ethanol, and in preparations utilising live cells. This indicated that it was not necessary to permeabilise the cells by fixation in order to render the antigen accessible to the antibody. Electron microscopy studies localised the antigen outside the cell surface, and these along with the above data and the resistance of the antigen to extraction with high salt and non-ionic detergent from a monolayer culture of EC were compatible with the hypothesis that the antigen was located in the pericellular matrix. It was also observed that the antigen disappeared from the cell surface during the spontaneous differentiation of human EC cells in vitro (Pera et al. 1989).