Decrease in Human Lymphocyte Surface Glycoconjugates in Leukemia As Demonstrated by Lectin Binding.

Qualitative variations in the glycoconjugates which make up the lectin receptor sites on the membranes of leukemic lymphocytes, compared with those of normal cells, have been studied by the use of three tritiated lectins: Robinia pseudoacacia lectin, Concanavalin A and Ricinus communis (var. Sanquineus) agglutinin (RCA 120). The binding specificity of these lectins has been demonstrated using specific determinants: alpha-methylmannoside and galactose for Concanavalin A and Ricinus communis agglutinin respectively. For the Robinia lectin this specificity was determined by saturation of the receptor sites with the unlabeled Robinia lectin before the addition of isotopically labeled Robinia lectin. The results show a decrease in the number of receptor sites on the leukemia cells, especially in chronic lymphoid leukemia, relative to that on normal cells. The apparent affinity constants of leukemic cells in all cases remain higher than those of normal cells.