Abstract
Changes in the cell membranes after infection or transformation of cells by oncogenic viruses have been demonstrated using a plant agglutinin, Concanavalin A (Con. A) isolated from Jack beans. Upon infection or transformation of cells by oncogenic viruses, the cells agglutinate in the presence of Con. A (Inbar & Sachs, 1969; Ben-Bassat, Inbar & Sachs, 1970; Benjamin & Burger, 1970). Moore & Temin (1971) reported a lack of correlation between transformability by RNA tumor viruses and agglutinability of cells by Con. A. Recent evidence (Cline & Livingston, 1971; Ozanne & Sambrook, 1971; Arndt-Jovin & Berg, 1971; Inbar, Ben-Bassat & Sachs, 1971) has suggested that both normal and transformed cells have the same number of Con. A binding sites but agglutinate differentially to a given concentration of Con. A. Nicolson (1971) showed that single Con. A binding sites at the surface of normal cells are randomly distributed whereas in transformed cells the Con. A sites are present in clusters.