A sialoglycoprotein from human leukocytes functions as a ligand for P-selectin.
P-selectin (CD62P), a Ca(2+)-dependent lectin expressed on activated platelets and endothelial cells, functions as a receptor for myeloid and monocytoid cells. Previous reports have described a homodimeric sialoglycoprotein from human leukocytes and HL-60 cells specifically recognized by P-selectin. We describe here a panel of monoclonal antibodies prepared against high molecular weight fractions of HL-60 cell membranes. These antibodies are of IgM isotype, bind to a approximately 240-kDa protein from human leukocyte membranes which is also reactive with P-selectin. They recognize a Ca(2+)-dependent, sialidase-sensitive determinant on myeloid and monocytoid cell lines. Each antibody specifically inhibits adhesion of neutrophils or HL-60 cells to: 1) purified P-selectin, 2) thrombin-stimulated platelets, and 3) phorbol 12-myristate 13-acetate-activated endothelial cells. These results suggest that the sialoglycoprotein recognized by this panel of monoclonal antibodies may function as a cell surface ligand for P-selectin.
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Cell Biology and Inflammation Research, Upjohn Laboratories, Kalamazoo, Michigan 49001.
Raycroft
L
L
Asa
D
D
Anderson
D C
DC
Geng
J G
JG
D000595:Amino Acid Sequence; D000911:Antibodies, Monoclonal; D002448:Cell Adhesion; D000939:Epitopes; D006801:Humans; D066298:In Vitro Techniques; D007962:Leukocytes / Q000737:chemistry* / Q000166:cytology; D008024:Ligands; D008969:Molecular Sequence Data; D009504:Neutrophils / Q000166:cytology; D019007:P-Selectin; D010980:Platelet Membrane Glycoproteins / Q000378:metabolism*; D012795:Sialoglycoproteins / Q000097:blood* / Q000737:chemistry; D014407:Tumor Cells, Cultured
D000911:Antibodies, Monoclonal; D000939:Epitopes; D008024:Ligands; D019007:P-Selectin; D010980:Platelet Membrane Glycoproteins; D012795:Sialoglycoproteins