Binding of [3H]Concanavalin A to Normal and Transformed Cells

Investigation of the factors influencing [3H]concanavalin A binding to normal and transformed cells has led us to develop a binding assay in which cells are incubated with [3H]concanavalin A for 5 min at 0° at pH 7.2 and 1.0 mm Mg2+. Under such conditions we have found that transformed cells bind 3.5 to 5 times more [3H]concanavalin A than does the normal interphase cell. We have also used this assay to demonstrate that normal cells treated with proteases and normal cells in mitosis bind more [3H]concanavalin A than does the normal interphase cell. These data demonstrate that there are more concanavalin A receptor sites exposed on the transformed cell than on the normal cell. However this increase in agglutinin receptor sites cannot, by itself, explain the increase in agglutinability demonstrated by transformed cells as compared to normal cells.