Binding of concanavalin A to rat, normal human, and chronic lymphatic leukemia lymphocytes.

This study was aimed to find a correlation between the extent of concanavalin A (Con A) binding to lymphocytes and the blastogenic effect of the lectin on these cells. 63Ni-labeled Con A was used in the lectin-binding experiments. Binding of Con A to a small fraction (approximately 3#{176}/o) of Con A binding sites in rat lymphocytes is required for the maximal stimulation of RNA synthesis. Binding of Con A to additional sites resulted in a less stimulatory effect. Lymphocytes from patients with chronic lymphatic leukemia (CLL) are impaired in their blastogenic response to Con A. Maximal stimulation of DNA synthesis induced by Con A in CLL lymphocytes is attained by treatment of the cells with the lectin at concentrations that are smaller than those required for the induction of maximal DNA synthesis in normal lymphocytes. The number of Con A binding sites in CLL lymphocyte is smaller than in normal lymphocyte.