Myeloid cells roll on L-selectin: Evidence for mucin-like ligand activity on HL-60 cells distinct from P-selectin glycoprotein ligand-1

In addition to leukocyte-endothelial interactions, L-selectin has been reported to contribute to leukocyte-leukocyte adhesion. We report that resting human neutrophils and HL-60 promyelocytes roll on recombinant L-selectin immobilized on the wall of a parallel plate flow chamber. Adhesion was calcium-dependent and inhibited by an L-selectin antibody. Incubation of HL-60 cells with O-sialoglycoprotein endopeptidase, chymotrypsin, or neuraminidase blocked adhesion to L-selectin. PSGL-1/αt(1,3)fucosyltransferase-VII (PSGL-1/FucT-VII) transfectants adhered to L-selectin, demonstrating that PSGL-1 may serve as a ligand for L-selectin. Monoclonal antibodies against P-selectin glycoprotein ligand-1 (PSGL-1), PL1 and KPL1, inhibited HL-60 rolling on P-selectin, but not L-selectin. An HL-60 detergent lysate, affinity purified using wheat germ lectin, supported rolling of L-selectin and P-selectin transfectants. Treatment of the adsorbed lysate with PL1 failed to block rolling of L-selectin transfectants. Immunodepletion of PSGL-1 from the lysate significantly inhibited adhesion of P-selectin transfectants, but not L-selectin transfectants, indicating that HL-60 cells express ligand activity for L-selectin that is distinct from PSGL-1. These findings demonstrate that neutrophils and HL-60 cells express sialylated and O-linked glycoprotein ligands for L-selectin that support rolling under flow conditions.