Modifications of lectin binding on human leukemic cells after neuraminidase treatment

Cell surface modifications after vibrio cholerae neuraminidase treatment were investigated using three different tritiated lectins: Concanavalin A, Ricinus sanguineus agglutinin (R.S.A.) and Robinia pseudoacacia lectin. Lectin binding measurements were performed on untreated and enzyme treated cells. The cells used were from chronic and acute leukemic donors. After neuraminidase treatment, a significant increase in the number of receptor sites, from 1 to 3 times, was found in all cases tested and for all three lectins utilized with only one exception. The affinity constant was generally decreased after neuraminidase treatment. The increase in number lectin binding sites, indicating extensive modification of the cell surface, is completely consistant with the known importance of sialic acid in determining immunogenicity.