LECTIN-BINDING AND UPTAKE IN HUMAN (MYELO)MONOCYTIC CELL-LINES - HL-60 AND U937

The terminal carbohydrate residues of the human (myelo)monocytic cell lines HL60 and two subclones of U937 were investigated by the use of l ectins. Several terminal carbohydrate residues, including N-acetylgluc osamine and carbohydrates of the complex type, were detected on all th ree cell lines. Except for galactose residues, the two subclones of U9 37 had almost identical terminal carbohydrate residues. The difference s between the two U937 subclones and HL60 were more pronounced, the la tter expressing fucose residues, which might be part of the CD15 cell adhesion molecules. Some of the differences of the carbohydrate residu es between the cell lines could be attributed to their differentiation within the myelomonocytic cell lineage. Lectins that bound to the cel l surface were internalized via either clathrin-coated pits and vesicl es or nonspecific endocytosis, indicating that functionally different classes of cell surface glycoproteins are involved in lectin binding a nd internalization.