Binding of Lectins to Leukemic Cell Lines

The binding of 12 different fluorescein-conjugated lectins to 10 ALL (acute lymphoblastic leukemia) cell lines and two cell lines derived from patients in blast crisis of myeloid leukemia was examined. The specificity of the membrane fluorescence was demonstrated by inhibition with various saccharides. Three of the lectins bound to all cell lines, four bound to only some of the lines, and five were not bound. There was no correlation between the binding pattern and the immunological phenotype of the cultured lymphoblasts. The lectin from Lens culinaris, however, in the experimental condition used (incubation at 4 degrees C, fluorescein conjugation at pH 8.5), bound only to the cell membranes of 'Ia-like antigen, positive cell lines. Although three lectins (Lens culinaris, Pisum sativum, concanavalin A) had an identical monosaccharide specificity, they bound to different cell lines. Membrane fluorescence with the lectins from Helix pomatia, Arachis hypogea, and Ricinus communis (MW 60,000) was achieved after treatment with neuraminidase. It was shown that binding of the lectins from Helix pomatia and Ricinus communis 60 was effected by enzymatically exposed glycoproteins, whereas the lectin Arachis hypogea was bound via neuraminidase which stuck to the cell membrane.