Embryonic and Neoplastic Cell Surfaces: Availability of Receptors for Concanavalin A and Wheat Germ Agglutinin

Embryonic tissue cells dissociated with ethylenediaminetetraacetate are readily agglutinated by the carbohydrate-binding protein concanavalin A. In this property, they resemble transformed, neoplastic cells; and they differ from untransformed adult cells, which are agglutinated by concanavalin A only after their receptors are unmasked by proteolytic treatment. Receptor sites for wheat germ agglutinin are also present on the surface of embryonic cells, but in a masked form, as on untransformed adult culture cells; they can be unmasked by treatment of the cells with trypsin. Concanavalin A binding sites on embryonic cells may function in cell contact and cell organization during embryonic morphogenesis and differentiation and later become masked in adult cells. The unmasking of these sites in neoplastic cells may represent a return, in this respect, to a condition resembling that of embryonic cells and may be related to cell mobility associated with infiltration and metastasis.